Intergovernmental Oceanographic Commission of UNESCO International Tsunami Information Centre

UNESCO 2006

IOC/INF-1221 Hawaii, January 2006

Original: English The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of UNESCO concerning the legal status of any country or territory, or its authorities, or concerning the delimitation of the frontiers of any country or territory. For bibliographic purpose, this document should be cited as follows:

UNESCO-IOC. Tsunami Glossary. IOC Information document No. 1221. Paris, UNESCO, 2006. Printed by Servicio Hidrográfico y Oceanográfica de la Armada de Chile Errázuriz 254 – Playa Ancha – Valparaíso – Chile www.shoa.cl - shoa@shoa.cl Published by the United Nations Educational, Scientific and Cultural Organization 7 Place de Fontenoy, 75 352 Paris 07 SP, France © UNESCO 2006

CHARACTERISTICS OF THE TSUNAMI PHENOMENA

A tsunami travels outward from the source regionas a series of waves. Its speed depends upon thedepth of the water, and consequently the wavesundergo accelerations or decelerations in passingrespectively over an ocean bottom of increasing ordecreasing depth. By this process the direction ofwave propagation also changes, and the waveenergy can become focused or defocused. In thedeep ocean, tsunami waves can travel at speedsof 500 to 1,000 kilometers (km) per hour. Near theshore, however, a tsunami slows down to just afew tens of kilometers per hour. The height of atsunami also depends upon the water depth. Atsunami that is just a meter in height in the deepocean can grow to tens of meters at the shoreline.Unlike familiar wind-driven ocean waves that areonly a disturbance of the sea surface, the tsunamiwave energy extends to the ocean bottom. Nearthe shore, this energy is concentrated in thevertical direction by the reduction in water depth,and in the horizontal direction by a shortening ofthe wavelength due to the wave slowing down.

Tsunamis have periods (the time for a single wavecycle) that may range from just a few minutes toas much as an hour or exceptionally more. At theshore, a tsunami can have a wide variety ofexpressions depending on the size and period ofthe waves, the near-shore bathymetry and shapeof the coastline, the state of the tide, and otherfactors. In some cases a tsunami may only inducea relatively benign flooding of low-lying coastalareas, coming onshore similar to a rapidly risingtide. In other cases it can come onshore as a bore- a vertical wall of turbulent water full of debris thatcan be very destructive. In most cases there isalso a drawdown of sea level preceding crests ofthe tsunami waves that results in a receding of thewaterline, sometimes by a kilometer or more.Strong and unusual ocean currents may alsoaccompany even small tsunamis. Damage and destruction from tsunamis is thedirect result of three factors: inundation, waveimpact on structures, and erosion. Deaths occurby drowning and physical impact or other traumawhen people are caught in the turbulent, debris-laden tsunami waves. Strong tsunami-induced

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Photo courtesy of Bishop Museum Archives.

currents have led to the erosion of foundationsand the collapse of bridges and seawalls.Floatation and drag forces have moved housesand overturned railroad cars. Tsunami associatedwave forces have demolished frame buildings andother structures. Considerable damage also iscaused by floating debris, including boats, cars,and trees that become dangerous projectiles thatmay crash into buildings, piers, and other vehicles.Ships and port facilities have been damaged bysurge action caused by even weak tsunamis. Firesresulting from oil spills or combustion fromdamaged ships in port, or from ruptured coastal oilstorage and refinery facilities, can cause damagegreater than that inflicted directly by the tsunami.Other secondary damage can result from sewageand chemical pollution following the destruction.Damage of intake, discharge, and storage facilitiesalso can present dangerous problems. Ofincreasing concern is the potential effect oftsunami drawdown, when receding watersuncover cooling water intakes associated withnuclear plants.

AIR-COUPLED TSUNAMI

Synonym for atmospheric tsunami.

ATMOSPHERIC TSUNAMI

Tsunami-like waves generated by a rapidlymoving atmospheric pressure front moving over ashallow sea at about the same speed as thewaves, allowing them to couple.

LOCAL TSUNAMI

A tsunami from a nearby source for which itsdestructive effects are confined to coasts within100 km of the source. A local tsunami is usuallygenerated by an earthquake, but can also becaused by a landslide, or a pyroclastic flow from avolcanic eruption.

MICROTSUNAMI

A tsunami of such small amplitude that it must beobserved instrumentally and is not easilydetected visually.

Numerical modelling snapshots of the water surface 10minutes after a pyroclastic flow on the southeastern part ofMonserrat Island led to a submarine landslide and thegeneration of a tsunami.

Damaged caused by the 22 May 1960 Chilean tsunami.Photo courtesy of Ilustre Municipalidad de Maulin, USGS Circular 1187.

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HISTORICAL TSUNAMI

A tsunami documented to occur througheyewitness or instrumental observation within thehistorical record.

OCEAN-WIDE TSUNAMI

A tsunami capable of widespread destruction, notonly in the immediate region of its generation, butacross an entire Ocean. All ocean-wide tsunamishave been generated by major earthquakes.Synonym for teletsunami or distant tsunami.

MAREMOTO

Spanish term for tsunami.

PALEOTSUNAMI

Tsunami occurring prior to the historical record orfor which there are no written observations.

Paleotsunami research is based primarily on theidentification, mapping, and dating of tsunamideposits found in coastal areas, and theircorrelation with similar sediments found elsewherelocally, regionally, or across ocean basins. In oneinstance, the research has led to a new concernfor the possible future occurrence of greatearthquakes and tsunamis along the northwestcoast of North America. In another instance, therecord of tsunamis in the Kuril-Kamchatka regionis being extended much further back in time. Aswork in this field continues it may provide asignificant amount of new information about pasttsunamis to aid in the assessment of the tsunamihazard.

REGIONAL TSUNAMI

A tsunami capable of destruction in a particulargeographic region, generally within about 1,000km of its source. Regional tsunamis alsooccasionally have very limited and localizedeffects outside the region. Most destructive tsunami can be classified as localor regional, meaning their destructive effects areconfined to coasts within a hundred km, or up to athousand km, respectively, of the source -- usuallyan earthquake. It follows many tsunami relatedcasualties and considerable property damage alsocomes from these tsunami. Between 1975 and2005 there were 22 local or regional tsunami inthe Pacific and adjacent seas that resulted indeaths and property damage. For example, a regional tsunami in 1983 in theSea of Japan or East Sea, severely damagedcoastal areas of Japan, Korea, and Russia,causing more than $ 800 million in damage, andmore than 100 deaths. Then, after nine yearswithout an event, 11 locally destructive tsunamisoccurred in just a seven-year period from 1992 to1998, resulting in over 4,200 deaths and hundredsof millions of dollars in property damage. In mostof these cases, tsunami mitigation efforts in placeat the time were unable to prevent significantdamage and loss of life. However, losses fromfuture local or regional tsunamis can be reduced ifa denser network of warning centres, seismic andwater- level report ing stat ions, and better

communications are established to provide atimely warning, and if better programmes oftsunami preparedness and education can be putin place.

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Earthquakes generating tsunamis in the Southwest Pacific.Source: ITDB, 2005. Red circles show tsunamis causinggreatest damage according to the Imamura-Soloviev tsunamiintensity scale. Grey circles are non-tsunamigenicearthquakes. The size of the circle is scaled to the magnitudeof the earthquake.

Earthquakes generating tsunamis in the Mediterranean andconnected seas. Source: ITDB, 2005.

Earthquakes generating tsunamis in the Caribbean and adjacent seas. Source: ITDB, 2005.

TELETSUNAMI OR DISTANT TSUNAMI

A tsunami originating from a far away source,generally more than 1,000 km away. Less frequent, but more hazardous than regionaltsunamis, are ocean-wide or distant tsunamis.Usually starting as a local tsunami that causesextensive destruction near the source, thesewaves continue to travel across an entire oceanbasin with sufficient energy to cause additionalcasualties and destruction on shores more than a1,000 kilometres from the source. In the last4

More than 80% of the world’s tsunamis are observed in thePacific where large earthquakes occur as tectonic plates aresubducted along the Pacific Ring of Fire. Top: Epicenters ofall tsunamigenic earthquakes. Middle: Epicenters of tsunamiscausing damage or casualties. Bottom: Epicenters oftsunamis causing damage or casualties more than 1000 kmaway. Source: Pacific Tsunami Warning Center.

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The worst tsunami catastrophe in history occurredin the Indian Ocean on 26 December 2004, whena M9.3 earthquake off of the northwest coast ofSumatra, Indonesia produced a ocean-widetsunami that hit Thailand and Malaysia to the east,and Sri Lanka, India, the Maldives, and Africa tothe west as it traversed across the Indian Ocean.Nearly 250,000 people lost their lives, and morethan 1 million people were displaced, losing theirhomes, property, and their livelihoods. Themagnitude of death and destructiveness caused

200 years, there have been at least 21 destructiveocean-wide tsunamis. The most destructive Pacific-wide tsunami ofrecent history was generated by a massiveearthquake off the coast of Chile on 22 May 1960.All Chilean coastal towns between the 36th and44th parallels were either destroyed or heavilydamaged by the action of the tsunami and thequake. The combined tsunami and earthquake tollincluded 2,000 killed, 3,000 injured, 2,000,000homeless, and $550 million damage. Off the coastof Corral, Chile, the waves were estimated to be20 metres (67 feet) high. The tsunami caused 61deaths in Hawaii, 20 in the Philippines, and 138 inJapan. Estimated damages were US $50 million inJapan, US $24 million in Hawaii and severalmillions along the west coast of the United Statesand Canada. Distant wave heights varied fromslight oscillations in some areas to 12 metres (40feet) at Pitcairn Island, 11 metres at Hilo, Hawaii,and 6 metres at some places in Japan.

The tsunami of 26 December 2004 destroyed the nearby cityof Banda Aceh leaving only a few structures standing. Photocourtesy of Yuichi Nishimura, Hokkaido University.

immediate response by the world's leaders andled to the development of the Indian Oceantsunami warning and mitigation system in 2005.The event also raised awareness of tsunamihazards globally, and new systems wereestablished in the Caribbean, the Mediterraneanand Atlantic.

TSUNAMI EARTHQUAKE

An earthquake that produces an unusually largetsunami relative to the earthquake magnitude(Kanamori, 1972). Tsunami earthquakes arecharacterized by a very shallow focus, faultdislocations greater than several metres, and faultsurfaces smaller than those for normalearthquakes. They are also slow earthquakes,with slippage along their faults occurring moreslowly than would occur in normal earthquakes.The last events of this type were in 1992(Nicaragua) and 1996 (Chimbote, Peru).

TSUNAMI

Japanese term meaning wave (“nami”) in aharbour (“tsu”). A series of traveling waves ofextremely long length and period, usuallygenerated by disturbances associated withearthquakes occurring below or near the oceanfloor. (Also called seismic sea wave and,incorrectly, tidal wave). Volcanic eruptions,submarine landslides, and coastal rockfalls canalso generate tsunami, as can a large meteoriteimpacting the ocean. These waves may reachenormous dimensions and travel across entireocean basins with little loss of energy. Theyproceed as ordinary gravity waves with a typicalperiod between 10 and 60 minutes. Tsunamissteepen and increase in height on approachingshallow water, inundating low-lying areas, andwhere local submarine topography causes thewaves to steepen, they may break and causegreat damage. Tsunamis have no connection withtides; the popular name, tidal wave, is entirelymisleading

TSUNAMI SEDIMENTS

Sediments deposited by a tsunami. The finding oftsunami sediment deposits within the stratigraphicsoil layers provides information on the occurrenceof historical and paleotsunamis. The discovery ofsimilarly-dated deposits at different locations,sometimes across ocean basins and far from thetsunami source, can be used to map and infer thedistribution of tsunami inundation and impact.

Sediment layers deposited from successive waves of 26December 2004 Indian Ocean tsunami, as observed inBanda Aceh, Indonesia. Photo courtesy Yuichi Nishimura,Hokkaido University.

Tsunami generated by 26 May 1983, Japan Sea earthquakeapproaching Okushiri Island, Japan. Photo courtesy of TokaiUniversity.

Destruction along the waterfront of Hilo, Hawaii from thePacific-wide tsunami generated off the coast of UnimakIsland, Aleutian Island, USA on 1 April 1946.

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This section contains general terms used intsunami mitigation and in tsunami generation andmodelling.

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BREAKER

A sea-surface wave that has become so steep(wave steepness of 1/7) that the crest outracesthe body of the wave and it collapses into aturbulent mass on shore or over a reef. Breakingusually occurs when the water depth is less than1.28 times the wave height. Roughly, three kindsof breakers can be distinguished, dependingprimarily on the gradient of the bottom: a) spillingbreakers (over nearly flat bottom) which form afoamy patch at the crest and break gradually overa considerable distance; b) plunging breakers(over fairly steep bottom gradient) which peak up,curl over with a tremendous overhanging massand then break with a crash; c) surging breakers(over very steep bottom gradients) which do notspill or plunge but surge up the beach face.Waves also break in deep water if they build toohigh while being generated by the wind, but theseare usually short-crested and are termedwhitecaps.

An offshore or onshore structure, such as a wall,water gate, or other in-water wave-dissipatingobject that is used to protect a harbour or beachfrom the force of waves.

Eddies generated by the interactions of tsunami waves asthey hit the coast of Sri Lanka, 26 December 2004. Photocourtesy of Digital Globe.

BREAKWATER

Sea wall with stairway evacuation route used to protect acoastal town against tsunami inundation in Japan. Photocourtesy of River Bureau, Ministry of Land, Infrastructure andTransport, Japan.

EDDY

By analogy with a molecule, a “glob” of fluid withinthe fluid mass that has a certain integrity and lifehistory of its own; the activities of the bulk fluidbeing the net result of the motion of the eddies.

Water gate used to protect against tsunami waves onOkushiri Island, Japan. The gate begins to automaticallyclose within seconds after earthquake shaking triggers itsseismic sensors. Photo courtesy of ITIC.

ESTIMATED TIME OR ARRIVAL (ETA)

Time of tsunami arrival at some fixed location, asestimated from modeling the speed and refractionof the tsunami waves as they travel from thesource. ETA is estimated with very good precisionif the bathymetry and source are well known (lessthan a couple of minutes).

EVACUATION MAP

A drawing or representation that outlines dangerzones and designates limits beyond which peoplemust be evacuated to avoid harm from tsunamiwaves. Evacuation routes are sometimedesignated to ensure the efficient movement ofpeople out of the evacuation zone to evacuationshelters.

Inundation and Evacuation Map created for the coastal townof Pucusana, Peru.

HISTORICAL TSUNAMI DATA

Historical data are available in many forms and atmany locations. These forms include publishedand unpublished catalogs of tsunami occurrences,personal narratives, marigraphs, tsunamiamplitude, run-up and inundation zonemeasurements, field investigation reports,newspaper accounts, film or video records.

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Elevated platform used for tsunami evacuation that alsoserves as a high-elevation scenic vista point for tourist.Okushiri Island, Japan. Photo courtesy of ITIC.

Emergency shelter building that also acts as communitycenter and Museum for Disaster Prevention. Kisei, MiePrefecture, Japan. The building is 22-m high, has five floorscovering 320 m2 , and holds 500 persons. Info courtesy ofhttp://www.webmie.or.jp.

TRAVEL TIME

Time required for the first tsunami wave topropagate from its source to a given point on acoastline.

TRAVEL TIME MAP

Map showing isochrons or lines of equal tsunamitravel time calculated from the source outwardstoward terminal points on distant coastlines.

SEICHE

A seiche may be initiated by a standing waveoscillating in a partially or fully enclosed body ofwater. May be initiated by long period seismicwaves (an earthquake), wind and water waves, ora tsunami.

SEISMIC SEA WAVE

Tsunamis are sometime referred to as seismic seawaves because they are most often generated byearthquakes.

Z

Travel-times (in hours) for the 22 May 1960 Chile tsunamicrossing the Pacific basin. This tsunami was extremelydestructive along the nearby coast of Chile, and thetsunami also caused significant destruction and casualtiesas far away as Hawaii and Japan. The awareness andconcern raised by this Pacific-wide tsunami ultimately led tothe formation of the TWSP and PTWS.

TSUNAMI BORE

A steep, turbulent, rapidly moving tsunami wavefront, typically occurring in a river mouth orestuary.

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Massive destruction in the town of Aonae on Okushiri Island, Japan caused by the regional tsunami of 12 July 1993. Photo courtesy of Dr. Eddie Bernard, NOAA PMEL.

power plants, water supply installations, etc.Indirect secondary tsunami damage can be: 1)Damage by fire of houses, boats, oil tanks, gasstations, and other facilities; 2) environmentalpollution caused by drifting materials, oil, or othersubstances; 3) outbreak of disease of epidemicproportions which could be serious in denselypopulated areas.

Tsunami bore entering Wailua River, Hawaii during the 1946Aleutian Island tsunami. Photo courtesy of Pacific TsunamiMuseum.

TSUNAMI DAMAGE

Loss or harm caused by a destructive tsunami.More specifically, the damage caused directly bytsunamis can be summarized into the following: 1)deaths and injuries; 2) houses destroyed, partiallydestroyed, inundated, flooded, or burned; 3) otherproperty damage and loss; 4) boats washed away,damaged or destroyed; 5) lumber washed away;6) marine installations destroyed, and; 7) damageto public utilities such as railroads, roads, electric

Banda Aceh, Sumatra, Indonesia. The tsunami of 26December 2004 completely razed coastal towns andvillages, leaving behind only sand, mud, and water (middle)where once there had been thriving communities of homes,offices, and green space. Photo courtesy of DigitalGlobe.

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TSUNAMI DISPERSION

Redistribution of tsunami energy, particularly as afunction of its period, as it travels across a body ofwater.

TSUNAMI GENERATION

Tsunamis are most frequently caused byearthquakes, but can also result from landslides,volcanic eruptions, and very infrequently bymeteorites or other impacts upon the oceansurface.Tsunamis are generated primarily bytectonic dislocations under the sea which arecaused by shallow focus earthquakes along areasof subduction. The upthrusted and downthrustedcrustal blocks impart potential energy into theoverlying water mass with drastic changes in thesea level over the affected region. The energyimparted into the water mass results in tsunamigeneration, i.e. energy radiating away from thesource region in the form of long period waves.

Most tsunamis are generated by large, shallow, thrustearthquakes that occur as a tectonic plate is subducted.Shallow earthquakes also occur along spreading ridges, butthese are not large enough to cause tsunamis. Large,shallow earthquakes also occur along transform faults, butthere is only minor vertical motion during the faulting so notsunamis are generated.

Tsunamis can be generated by submarine landslides, or bysubaerial landslides that enter the water. Courtesy of LDG-France.

TSUNAMI FORERUNNER

A series of oscillations of the water level precedingthe arrival of the main tsunami waves mainly dueto the resonance in bays and shelves that couldoccur before the arrival of the main tsunami.

TSUNAMI EDGE WAVE

Wave generated by a tsunami that travels alongthe coast.

Tsunamis are most often generated by shallowearthquakes.

TSUNAMI GENERATION THEORY

The theoretical problem of generation of thegravity wave (tsunami) in the layer of elastic liquid(an ocean) occurring on the surface of elastic solidhalf-space (the crust) in the gravity field can bestudied with methods developed in the dynamictheory of elasticity. The source representing anearthquake focus is a discontinuity in the tangentcomponent of the displacement on some elementof area within the crust. For conditionsrepresentative of the Earth's oceans, the solutionof the problem differs very little from the jointsolution of two more simple problems: the problemof generation of the displacement field by thegiven source in the solid elastic half-space withthe free boundary (the bottom) considered quasi-static and the problem of the propagation ofgravity wave in the layer of heavy incompressibleliquid generated by the known (from the solution ofthe previous problem) motion of the solid bottom.There is the theoretical dependence of the gravitywave parameters on the source parameters(depth and orientation). One can roughly estimatethe quantity of energy transferred to the gravitywave by the source. In general, it corresponds tothe estimates obtained with empirical data. Also,tsunamis can be generated by other differentmechanisms such as volcanic or nuclearexplosions, landslides, rock falls, and submarineslumps.

Tsunamis can be generated by pyroclastic flowsassociated with volcanic eruptions. Courtesy of LDG-France.

TSUNAMI HAZARD

The probability of that a tsunami of a particularsize will strike a particular section of coast.

TSUNAMI HAZARD ASSESSMENT

Documentation of tsunami hazards for a coastalcommunity is needed to identify populations andassets at risk, and the level of that risk. Thisassessment requires knowledge of probabletsunami sources (such as earthquakes, landslides,volcanic eruption), their likelihood of occurrence,and the characteristics of tsunamis from thosesources at different places along the coast. Forthose communities, data of earlier (historical andpaleotsunamis) tsunamis may help quantify thesefactors. For most communities, however, only verylimited or no past data exist. For these coasts,numerical models of tsunami inundation canprovide estimates of areas that will be flooded inthe event of a local or distant tsunamigenicearthquake or a local landslide.

TSUNAMI IMPACT

Although infrequent, tsunamis are among the mostterrifying and complex physical phenomena andhave been responsible for great loss of life andextensive destruction to property. Because oftheir destructiveness, tsunamis have importantimpacts on the human, social and economicsectors of societies. Historical records show thatenormous destruction of coastal communitiesthroughout the world has taken place and that thesocio-economic impact of tsunamis in the past hasbeen enormous. In the Pacific Ocean where

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Global tsunami source zones. Tsunami hazards exist in alloceans and basins, but occur most frequently in the PacificOcean. Tsunamis can occur anywhere and at any timebecause earthquakes cannot be accurately predicted.

Estimated tsunami inundation at Iquique, Chile, based onnumerical model results.

TSUNAMI NUMERICAL MODELING

Mathematical descriptions that seek to describethe observed tsunami and its effects. Often the only way to determine the potentialrunups and inundation from a local or distanttsunami is to use numerical modelling, since datafrom past tsunamis is usually insufficient. Modelscan be initialized with potential worst casescenarios for the tsunami sources or for the wavesjust offshore to determine corresponding worstcase scenarios for runup and inundation. Modelscan also be initialized with smaller sources tounderstand the severity of the hazard for the lessext reme but more f requent events . Th isinformation is then the basis for creating

tsunami evacuation maps and procedures. Atpresent, such modelling has only been carried outfor a small fraction of the coastal areas at risk.Sufficiently accurate modelling techniques haveonly been available in recent years, and thesemodels require training to understand and usecorrectly, as well as input of detailed bathymetricand topographic data in the area being modeled. Numerical models have been used in recent yearsto simulate tsunami propagation and interactionwith land masses. Such models usually solvesimilar equations but often employ differentnumerical techniques and are applied to differentsegments of the total problem of tsunamipropagation from generation regions to distantareas of runup. For example, several numericalmodels have been used to simulate the interactionof tsunamis with islands. These models have usedfinite difference, finite element, and boundaryintegral methods to solve the linear long waveequations. These models solve these relativelysimple equations and provide reasonablesimulations of tsunamis for engineering purposes. Historical data are often very limited for mostcoastlines. Consequently, numerical modellingmay be the only way to estimate potential risk.Techniques now exist to carry out thisassessment. Computer software and the trainingnecessary to conduct this modelling are availablethrough programmes such as the IOC TsunamiInundation Modelling Exchange (TIME)Programme.

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the majority of these waves have been generated,the historic record shows tremendous destructionwith extensive loss of life and property. In Japan, which has one of the most populatedcoastal regions in the world and a long history ofearthquake activity, tsunamis have destroyedentire coastal populations. There is also a historyof severe tsunami destruction in Alaska, theHawaiian Islands, and South America, althoughrecords for these areas are not as extensive. Thelast major Pacific-wide tsunami occurred in 1960.Many other local and regional destructivetsunamis have occurred with more localizedeffects.

Calculated maximum tsunami wave heights for a M9.0Cascadia subduction zone earthquake. The model wascalculated after tsunami deposits found in Japan andelsewhere suggested that a repeat of the 1700 Cascadiagreat earthquake would generate a destructive teletsunami.Courtesy of Kenji Satake, Geological Survey of Japan.

TSUNAMI OBSERVATION

Notice, observation or measurement of sea levelfluctuation at a particular point in time caused bythe incidence of a tsunami on a specific point.

TSUNAMI PREPAREDNESS

Readiness of plans, methods, procedures andactions taken by government officials and thegeneral public for the purpose of minimizingpotential risk and mitigating the effects of futuretsunamis. The appropriate preparedness for awarning of impending danger from a tsunamirequires knowledge of areas that could beflooded (tsunami inundation maps) andknowledge of the warning system to know whento evacuate and when it is safe to return.

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Complex numerical model calculated to match the 1958Lituya Bay, Alaska landslide-generated local tsunami whichcaused the largest runup ever recorded (525 m). Thecomplex model matches very closely the detail of the secondorder eddies and splash effects that laboratory experimentsshowed. Courtesy of Galen Gisler, Los Alamos NationalLaboratory.

1946 Aleutian Islands tsunami rushing ashore in Hilo, Hawaii.Photo courtesy of Pacific Tsunami Museum.

International tsunami hazard sign.

TSUNAMI PROPAGATION

Tsunamis travel outward in all directions from thegenerating area, with the direction of the mainenergy propagation generally being orthogonal tothe direction of the earthquake fracture zone.Their speed depends on the depth of water, sothat the waves undergo accelerations anddecelerations in passing over an ocean bottom ofvarying depth. In the deep and open ocean, theytravel at speeds of 500 to 1,000 km per hour (300to 600 miles per hour). The distance betweensuccessive crests can be as much as 500 to 650km (300 to 400 miles); however, in the openocean, the height of the waves is generally lessthan a meter (three feet) even for the mostdestructive teletsunamis, and the waves passunnoticed. Variations in tsunami propagationresult when the propagation impulse is stronger inone direction than in others because of theorientation or dimensions of the generating areaand where regional bathymetric and topographicfeatures modify both the wave form and rate ofadvance. Specifically tsunami waves undergo a

Model of tsunami propagation in the southeast Pacific, ninehours after generation. Source: Antofagasta, Chile (30 July1995). Courtesy of LDG-France.

TSUNAMI RISK

The probability of a particular coastline beingstruck by a tsunami multiplied by the likelydestructive effects of the tsunami and by thenumber of potential victims. In general terms,risk is the hazard multiplied by the exposure.

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process of wave refract ion and ref lect ionthroughout their travel. Tsunamis are unique inthat the energy extends through the entire watercolumn from sea surface to the ocean bottom. It isthis characteristic that accounts for the greatamount of energy propagated by a tsunami.

TSUNAMI RESONANCE

The continued reflection and interference oftsunami waves from the edge of a harbour ornarrow bay which can cause amplification of thewave heights, and extend the duration of waveactivity from a tsunami.

TSUNAMI SIMULATION

Numerical model of tsunami generation,propagation, and inundation.

Evacuation Route sign used in Chile. Photo courtesy of ITIC.

TSUNAMI SOURCE

Point or area of tsunami origin, usually the site ofan earthquake, volcanic eruption, or landslide thatcaused large-scale rapid displacement of thewater to initiate the tsunami waves.

TSUNAMIC

Having features analogous to those of a tsunamior descriptive of a tsunami.

TSUNAMIGENIC

Having generated a tsunami: a tsunamigenicearthquake, a tsunamigenic landslide.

TSUNAMI VELOCITY OR SHALLOW WATER VELOCITY

The velocity of an ocean wave whose length issufficiently large compared to the water depth (i.e.,25 or more times the depth) can be approximatedby the following expression:

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Wave height and water depth. In the open ocean, atsunami is often only a tens of centimeters high, but itswave height grows rapidly in shallow water. Tsunamiwave energy extends from the surface to the bottom inthe deepest waters. As the tsunami attacks the coastline,the wave energy is compressed into a much shorterdistance creating destructive, life threatening waves.

TSUNAMI ZONATION (TSUNAMI ZONING)

Designation of distinctive zones along coastalareas with varying degrees of tsunami risk andvulnerability for the purpose of disasterpreparedness, planning, construction codes, orpublic evacuation.

c = √(gh)

Where: c: is the wave velocity g: the acceleration of gravity h: the water depth. Thus, the velocity of shallow-water waves isindependent of wave length L. In water depthsbetween ½ L and 1/25 L it is necessary to use amore precise expression:

c = √ ( (gL/2π)[tanh(2 π h/L)])

Destruction of Hilo Harbor, Hawaii, 1 April 1946. The tsunamigenerated off the coast of Unimak Island, Aleutian Islandsraced across the Pacific, coming ashore in Hawaii less thanfive hours later. Photo courtesy of NOAA.

This section contains terms used to measure anddescribe tsunami waves on mareographs and inthe field during a survey, and terms used todescribe the size of the tsunami.

ARRIVAL TIME

Time of the first maximum of the tsunami waves.

CREST LENGTH

The length of a wave along its crest. Sometimescalled crest width.

DROP

The downward change or depression in sea levelassociated with a tsunami, a tide, or some longterm climatic effect.

ELAPSED TIME

Time between the maximum level arrival time andthe arrival time of the first wave.

INITIAL RISE

Time of the first minimum of the tsunami waves.

INTENSITY

Extreme strength, force, or energy.

INUNDATION (MAXIMUM)

Maximum horizontal penetration of the tsunamifrom the shoreline. A maximum inundation ismeasured for each different coast or harbouraffected by the tsunami.

Tsunami inundation generated by the earthquake of26 May 1983, at Oga aquarium in Japan. Photo courtesyof Takaaki Uda, Public Works Research Institute, Japan.

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INUNDATION AREA

Area flooded with water by the tsunami.

INUNDATION

The horizontal distance inland that a tsunamipenetrates, generally measured perpendicularlyto the shoreline.

INUNDATION LINE

Inland limit of wetting, measured horizontally fromthe mean sea level (MSL) line. The line betweenliving and dead vegetation is sometimes used as areference. In tsunami science, the landward limitof tsunami runup.

LEADING WAVE

First arriving wave of a tsunami. In some cases,the leading wave produces an initial depression ordrop in sea level, and in other cases, an elevationor rise in sea level. When a drop in sea leveloccurs, sea level recession is observed.

MAGNITUDE

A number assigned to a quantity by means ofwhich the quantity may be compared with otherquantities of the same class.

MEAN HEIGHT

Average height of a tsunami measured from thetrough to the crest after removing the tidalvariation.

OVERFLOW

A flowing over; inundation.

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POST-TSUNAMI SURVEY

Tsunamis are relatively rare events and most oftheir evidence is perishable. Therefore, it is veryimportant that reconnaissance surveys beorganized and carried out quickly and thoroughly

Dark area shows inundation area from the 1964 Alaskatsunami. Photo courtesy of NGDC.

after each tsunami occurs, to collect detaileddata valuable for hazard assessment, modelvalidation, and other aspects of tsunamimitigation.

After a major tsunami, physical oceanographers, socialscientists, and engineers conduct post-tsunami surveys tocollect information. These data, including runup andinundation, deformation, scour, building and structuralimpact, wave arrival descriptions, and social impact, areimportant for designing better mitigation to reduce theimpacts of tsunami on life and property. Photo courtesy ofPhilip Liu, Cornell University.

In recent years, following each major destructivetsunami, a post-tsunami reconnaissance surveyhas been organized to make measurements ofrunups and inundation limits and to collectassociated data from eyewitnesses such as thenumber of waves, arrival time of waves, andwhich wave was the largest. The surveys havebeen organized primarily on an ad-hoc basis byInternational academic tsunami researchers. AP o s t - T s u n a m i S u r v e y F i e l d G u i d e(http://www.tsunamiwave.info/itic/contents.php?id=28) has been prepared by the PTWS to helpwith preparations of surveys, to identi fymeasurements and observations to be taken,

Post-tsunami survey measuring runup along a transectinland from the coast. Courtesy of ICMAM, Chennai, DOD,India.

RISE

The upward change or elevation in sea levelassociated with a tsunami, a tropical cyclone,storm surge, the tide, or other long term climaticeffect.

RUN-UP

1) Difference between the elevation of maximumtsunami penetration (inundation line) and the sea-level at the time of the tsunami. 2) Elevation reached by seawater measuredrelative to some stated datum such as mean sealevel, mean low water, sea level at the time of thetsunami attack, etc., and measured ideally at apoint that is a local maximum of the horizontalinundation. 3) In practical terms, runup is only measuredwhere there is a clear evidence of the inundationlimit on the shore.

RUN-UP DISTRIBUTION Set of tsunami run-up values measured orobserved along a coastline.

Tsunami stripped forested hills of vegetation leaving clearmarker of tsunami runup, Banda Aceh, 26 December 2004Sumutra tsunami. Photo courtesy of Yuichi Nishimura,Hokkaido University.

SIEBERG TSUNAMI INTENSITY SCALE

A descriptive tsunami intensity scale, which waslater modified into the Sieberg-Ambraseys tsunamiintensity scale described below (Ambraseys1962).

MODIFIED SIEBERG SEA-WAVE INTENSITY SCALE

1) Very light. Wave so weak as to be perceptibleonly on tide-gauge records. 2) Light. Wave noticed by those living along theshore and familiar with the sea. On very flatshores generally noticed. 3) Rather strong. Generally noticed. Flooding ofgently sloping coasts. Light sailing vessels or

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RECESSION

Drawdown of sea level prior to tsunami flooding.The shoreline moves seaward, sometimes by akilometre or more, exposing the sea bottom,rocks, and fish. The recession of the sea is anatural warning sign that a tsunami isapproaching.

and to standardize data collections. The TsunamiBulletin Board e-mail service has also been usedfor quickly organizing international surveys and forsharing of the observations from impacted areas.

North Shore, Oahu, Hawaii. During the 9 March 1957Aleutian Island tsunami, people foolishly explored theexposed reef, unaware that tsunami waves would return inminutes to inundate the shoreline. Photo by A. Yamauchi,courtesy of Honolulu Star-Bulletin.

Runup can often be inferred from the vertical extent of deadvegetation, from debris normally found at ground level thatare observed stuck on electric wires, in trees, or at otherheights, and from water line marks left on building walls. Inextreme cases, cars, boats, and other heavy objects havebeen lifted and deposited atop buildings. Banda Aceh,Indonesia, 26 December 2004. Photo courtesy of C.Courtney, Tetra Tech EMI.

SIGNIFICANT WAVE HEIGHT

The average height of the one-third highest wavesof a given wave group. Note that the compositionof the highest waves depends upon the extent towhich the lower waves are considered. In waverecord analysis, the average height of the highestone-third of a selected number of waves, thisnumber being determined by dividing the time ofrecord by the significant period. Also calledcharacteristic wave height.

SPREADING

When reference is made to tsunami waves, it isthe spreading of the wave energy over a widergeographical area as the waves propagate awayfrom the source region. The reason for thisgeographical spreading and reduction of waveenergy with distance traveled, is the sphericity ofthe earth. The tsunami energy wi l l beginconverging again at a distance of 90 degrees fromthe source. Tsunami waves propagating across al a rge oc ean unde rgo o the r changes i n

TSUNAMI AMPLITUDE

Usually measured on a sea level record, it is:1) the absolute value of the difference between aparticular peak or trough of the tsunami and theundisturbed sea level at the time, 2) half thedifference between an adjacent peak and trough,corrected for the change of tide between that peakand trough. It is intended to represent the trueamplitude of the tsunami wave at some point inthe ocean. However, it is often an amplitudemodified in some way by the tide gauge response.

Mareogram (sea level) record of a tsunami

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small boats carried away on shore. Slight damageto light structures situated near the coast. Inestuaries reversal of the river flow some distanceupstream. 4) Strong. Flooding of the shore to some depth.Light scouring on man-made ground.Embankments and dikes damaged. Lightstructures near the coasts damaged. Solidstructures on the coast injured. Big sailing vesselsand small ships carried inland or out to sea.Coasts littered with floating debris. 5) Very strong. General flooding of the shore tosome depth. Breakwater walls and solid structuresnear the sea damaged. Light structures destroyed.Severe scouring of cultivated land and littering ofthe coast with floating items and sea animals. Withthe exception of big ships all other type of vesselscarried inland or out to sea. Big bores in estuaryrivers. Harbour works damaged. People drowned.Wave accompanied by strong roar. 6) Disastrous. Partial or complete destruction ofman-made structures for some distance from theshore. Flooding of coasts to great depths. Bigships severely damaged. Trees uprooted orbroken. Many casualties.

configuration primarily due to refraction, butgeographical spreading is also very importantdepending upon the orientation, dimensions andgeometry of the tsunami source.

SUBSIDENCE (UPLIFT)

The permanent movement of land down(subsidence) or up (uplift) due to geologicprocesses, such as during an earthquake.

The 26 December 2004 earthquake resulted in 1.2 m of landsubsidence in the Car Nicobar, Nicobar Islands, India leavinghouses that were once above sea level now permanentlysubmerged. Photo courtesy of ICMAM, Chennai, DOD, India.

TSUNAMI INTENSITY

Size of a tsunami based on the macroscopicobservation of a tsunami's effect on humans,objects, including various sizes of marine vessels,and buildings. The original scale for tsunamis was published bySieberg (1923), and later modified by Ambraseys(1962) to create a six-category scale.Papadopoulus and Imamura (2001) proposed anew 12-grade intensity scale which is independentof the need to measure physical parameters likewave amplitude, sensitive to the small differencesin tsunami effects, and detailed enough for eachgrade to cover the many possible types of tsunamiimpact on the human and natural environment.The scale has 12 categories, similar to theModified Mercalli Intensity Scale used formacroseismic descriptions of earthquake intensity.

TSUNAMI MAGNITUDE

Size of a tsunami based on the measurement ofthe tsunami wave on sea level gauges and otherinstruments. The scale, originally descriptive and more similarto an intensity, quantifies the size by usingmeasurements of wave height or tsunami runup.Iida et al. (1972) described the magnitude (m) asdependent in logarithmic base 2 on the maximumwave height measured in the field, andcorresponding to a magnitude range from -1 to 4: m = log2 Hmax Hatori (1979) subsequently extended this so-called Imamura-Iida scale for far-field tsunamis byincluding distance in the formulation. Soloviev(1970) suggested that the mean tsunami heightmay be another good indicator of tsunami size, sothat the mean tsunami height is equal to 1/squareroot (Hmax), and the maximum intensity would bethat measured nearest to the tsunami source. Avariation on this is the Imamura-Soloviev intensityscale I (Soloviev, 1972). Shuto (1993) hassuggested the measurement of H as the heightwhere specific types of impact or damage occur,thus proposing a scale which can be used as apredictive quantitative tool for macroscopic effects. Tsunami magnitudes have also been proposed

that are similar in form to those used to calculateearthquake magnitudes. These include the originalformula proposed by Abe (1979) for tsunamimagnitude, Mt, Mt = logH + B where H is the maximum single crest or troughamplitude of the tsunami waves (in metres) and Bis a constant, and the far-field applicationproposed by Hatori (1986) which adds a distancefactor into the calculation.

TSUNAMI PERIOD

Amount of time that a tsunami wave takes tocomplete a cycle. Tsunami periods typically rangefrom five minutes to two hours.

TSUNAMI PERIOD (DOMINANT)

Difference between the arrival time of the highestpeak and the next one measured on a water levelrecord.

TSUNAMI WAVE LENGTH

The horizontal distance between similar points ontwo successive waves measured perpendicular tothe crest. The wave length and the tsunami periodgive information on the tsunami source. Fortsunamis generated by earthquakes, the typicalwave length ranges from 20 to 300 km. Fortsunamis generated by landslides, the wave lengthis much shorter, ranging from hundreds of metresto tens of kilometres.

WATER LEVEL (MAXIMUM)

Difference between the elevation of the highestlocal water mark and the elevation of the sea-levelat the time of the tsunami. This is different frommaximum run-up because the water mark is oftennot observed at the inundation line, but maybehalfway up the side of a building or on a tree trunk.

WAVE CREST

1) The highest part of a wave. 2) That part of the wave above still water level.

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WAVE TROUGH

The lowest part of a wave.

This section contains terms to describe sea leveland the instruments used to measure tsunamis.

COTIDAL

Indicating equality with the tides or a coincidencewith the time of high or low tide.

LOW WATER

The lowest water level reached during a tidecycle. The accepted popular term is low tide.

MAREOGRAM OR MARIGRAM

1) Record made by a marigraph. 2) Any graphic representation of the rise and fall ofthe sea level, with time as abscissa and height asordinate, usually used to measured tides, mayalso show tsunamis.

2/17/96 IRIAN JAYA TSUNAMI

MAREOGRAPH

A recording tide gauge.

MEAN SEA LEVEL

The average height of the sea surface, basedupon hourly observation of tide height on the opencoast or in adjacent waters which have free

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DEEP-OCEAN ASSESSMENT AND REPORTING OF TSUNAMIS (DART)

An instrument for the early detection,measurement, and real-time reporting of tsunamisin the open ocean. Developed by the US NOAAPacific Marine Environmental Laboratory, theDART system consists of a seafloor bottompressure recording system capable of detectingtsunamis as small as one cm, and a mooredsurface buoy for real-time communications. Anacoustic link is used to transmit data from theseafloor to the surface buoy. The data are thenrelayed via a satellite link to ground stations,which demodulate the signals for immediatedissemination to the NOAA tsunami warningscentres. The DART data, along with state-of-the-art numerical modelling technology, are part of atsunami forecasting system package that willprovide site-specific predictions of tsunami impacton the coast. Mareograms of tsunami signals measured by an underwater

gauge located 50 km outside the entrance to Tokyo Bay inabout 50 m of water (upper trace), and another gauge locatedat the shore (lower trace). The tsunami is detected on theoutside gauge about 40 minutes before it reaches shore(arrows). The offshore gauge was developed by Japan's Portand Harbours Research Institute.

approximates the geoid. The geoid was assumedto be coincident with local mean sea level at 26tidal stations to obtain the Sea Level Datum of1929 (SLD 290). National Geodetic Vertical Datumof 1929 (NGVD 29) became a name change only;the same vertical reference system has been inuse in the United States since 1929. Thisimportant vertical geodetic control system is madepossible by a universally accepted, reference sealevel.

PROBABLE MAXIMUM WATER LEVEL

A hypothetical water level (exclusive of waverunup from normal wind-generated waves) thatmight result from the most severe combination ofhydrometeorological, geoseismic and othergeophysical factors that is considered reasonablypossible in the region involved, with each of thesefactors considered as affecting the locality in amaximum manner. This level represents thephysical response of a body of water to maximumapplied phenomena such as hurricanes, movingsquall lines, other cyclonic meteorological events,tsunamis, and astronomical tide combined withmaximum probable ambient hydrologicalconditions such as wave level with virtually no riskof being exceeded.

REFERENCE SEA LEVEL

The observed elevation differences betweengeodetic bench marks are processed throughleas t -squares ad jus tments to de te rmineorthometric heights referred to a common verticalreference surface, which is the reference sealevel. In this way, height values of all bench marksin the vertical control portion of a surveyingagency are made consistent and can becompared directly to determine differences ofelevation between bench marks in a geodeticreference system that may not be directlyconnected by lines of geodetic leveling. Thevertical reference surface in use in the UnitedS ta tes , a s i n mos t pa r t s o f t he wo r l d ,

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open coast or in adjacent waters which have freeaccess to the sea. These observations are to havebeen made over a “considerable” period of time. Inthe United States, mean sea level is defined asthe average height of the surface of the sea for allstages of the tide over a 19-year period. Selectedvalues of mean sea level serve as the sea leveldatum for all elevation surveys in the UnitedStates. Along with mean high water, mean lowwater, and mean lower low water, mean sea levelis a type of tidal datum.

REFRACTION DIAGRAMS

Models using water depths, direction of wave,separation angle, and ray separation between twoadjacent rays as input, produce the path of waveorthogonals, refraction coefficients, wave heights,and travel times.

SEA LEVEL

The height of the sea at a given time measuredrelative to some datum, such as mean sea level.

SEA LEVEL STATION

A system consisting of a device such as a tidegauge for measuring the height of sea level, adata collection platform (DCP) for acquiring,digitizing, and archiving the sea level informationdigitally, and often a transmission system fordelivering the data from the field station to acentral data collection centre. The specificrequirements of data sampling and datatransmission are dependent on the application.The GLOSS programme maintains a core networkof sea level stations. For local tsunamimonitoring, one-second sampled data streamsavailable in real time are required. For distanttsunamis, warning centres may be able to provideadequate warnings using data acquired in near-real time (one-minute sampled data transmittedevery 15 minutes). Sea level stations are alsoused for sea level rise and climate change studies,where an important requirement is for the veryaccurate location of the station as acquiredthrough surveying techniques.

TIDAL WAVE

1. The wave motion of the tides. 2. Often incorrectly used to describe a tsunami, storm surge, or other unusually high and therefore destructive water levels along a shore that are unrelated to the tides.

TIDE

The rhythmic, alternate rise and fall of the surface(or water level) of the ocean, and of bodies ofwater connected with the ocean such as estuariesand gulfs, occurring twice a day over most of theEarth and resulting from the gravitational attractionof the moon (and, in lesser degrees, of the sun)acting unequally on different parts of the rotatingEarth.

TIDE AMPLITUDE

One-half of the difference in height betweenconsecutive high water and low water; hence, halfof the tidal range.

TIDE GAUGE

A device for measuring the height (rise and fall) ofthe tide. Especially an instrument forautomatically making a continuous graphicrecord of tide height versus time.

GLOSS sea level stations employ a number of instruments tomeasure sea level, including down-looking radars to measuresea level. Port Louis, Mauritius. Photo courtesy of Universityof Hawaii Sea Level Center.

TIDE STATION

A place where tide observations are obtained.

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TSUNAMETER

An instrument for the early detection,measurement, and real-time reporting of tsunamisin the open ocean. The DART system is atsunameter.

Rarotonga sea level station, Avarua Harbor, Cook Islands.The fiberglass electronics package (a), antenna (b), solarpanel (c) were installed on a pier. Conduit (d) containingcables connecting the sensor, located at a depth of five feetbelow low-tide water level, to the data collection platformcontaining the electronics above, was externally attached tothe tube containing the sensor (e).

The IOC Global Tsunami Warning and MitigationSystems work in partnership with a number oforganizations and utilize specific acronyms todescribe system governance, and the differenttsunami information products.

COMMUNICATIONS PLAN FOR THE TSUNAMI WARNING SYSTEM

The operations manual for the Tsunami WarningSystem in various regions. The Plan provides ageneral overview of the operational proceduresand of the nature of tsunamis. It lists theseismographic and sea level stations participatingin the warning system, the methods ofcommunication between the stations and theWarning Centre, the criteria for the reporting andissuing of tsunami information messages by theWarning Centre, the recipients of the information,and the methods by which the messages are sent.Official contact information for emergencycommunications is included.

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FORECAST POINT

The location where the Tsunami Warning Centre may provide estimates of tsunami arrival time or wave height.

GLOSS Global Sea-Level Observing System. Acomponent of the Global Ocean ObservingSystem (GOOS). The UNESCO IOC establishedGLOSS in 1985 originally to improve the quality ofsea level data as input to studies of long-term sealevel change. It consists of a core network ofapproximately 300 stations distributed alongcontinental coastlines and throughout each of theworld's island groups. The GLOSS network alsosupports sea level monitoring for tsunami warningwith minimum operational standards of 15-minutedata transmissions of 1-minute sampled data.

GOOS Global Ocean Observing System. GOOS is apermanent global system for observations,modelling and analysis of marine and oceanvariables to support operational ocean servicesworldwide. The GOOS Project aims to provideaccurate descriptions of the present state of theoceans, including living resources; continuousforecasts of the future conditions of the sea for asfar ahead as possible; and the basis for forecastsof climate change. The GOOS Project Office,located at the IOC headquarters in Paris since1992, provides assistance in the implementationof GOOS.

GTS

Global Telecommunications System of the WorldMeteorological Organization (WMO) that directlyconnects national meteorological and hydrologicalservices worldwide. The GTS is widely used forthe near real time transmission of sea level datafor tsunami monitoring. The GTS and other robustcommunications methods are used for thetransmission of tsunami warnings.

ICG

Intergovernmental Coordination Group. Assubsidiary bodies of the UNESCO IOC, the ICGmeets to promote, organize, and coordinateregional tsunami mitigation activities, including theissuance of timely tsunami warnings. The ICG iscomposed of National Contacts from MemberStates in the region. Currently, there are ICG fortsunami warning and mitigation systems in thePacific, Indian Ocean, Caribbean and adjacentregions, and the north-eastern Atlantic, theMediterranean and connected seas.

ICG/CARIBE-EWS Intergovernmental Coordination Group forTsunami and other Coastal Hazards WarningSystem for the Caribbean and Adjacent Regionsestablished by Resolution XXIII-14 of the 23rdSession of the IOC General Assembly in 2005.The ICG is comprised principally of IOC MemberStates and regional organizations from theWider Caribbean Region. Through thecoordinating efforts of the IOCARIBE Sub-commission starting in 1993, a Group of Expertsformulated a proposal for the building of theIntra-Americas Tsunami Warning System thatwas endorsed by the IOC General Assembly in2002. (http://ioc3.unesco.org/cartws)

ICG/NEAMTWS Intergovernmental Coordination Group for theTsunami Early Warning and Mitigation System inthe North-eastern Atlantic, the Mediterranean andConnected Seas established by Resolution XXIII-13 of the 23rd Session of the IOC GeneralAssembly in 2005. The ICG is comprisedprincipally of IOC Member States bordering thenorth-eastern Atlantic and those bordering orwithin the Mediterranean or connected seas.(http://ioc3.unesco.org/neamtws)

ICG/PTWS Intergovernmental Coordination Group for thePacific Tsunami Warning and Mitigation System,renamed by Resolution ITSU-XX.1 of the 20thSession of the ICG/ITSU in 2005. Presently,there are 28 Member States. The ICG/PTWSwas formerly the ICG/ITSU. The ITIC inHonolulu serves as the PTWS Secretariat.(http://ioc3.unesco.org/ptws)

ICG/IOTWS Intergovernmental Coordination Group for theIndian Ocean Tsunami Warning and MitigationSystem established by Resolution XXIII-12 of the23rd Session of the IOC General Assembly in2005. The IOC Regional Programme Office inPerth, Australia, serves as the IOTWS Secretariat.Presently, there are 27 Member States.(http://ioc.unesco.org/indotsunami)

ICG/ITSU International Coordination Group for theInternational Tsunami Warning System in thePacific established by Resolution IV-6 of the 4thSession of the IOC General Assembly in 1965.The ICG/ITSU was renamed to the ICG/PTWS in2005. (http://www.tsunamiwave.info)

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IOC Intergovernmental Oceanographic Commissionof UNESCO. The IOC provides Member Statesof the Uni ted Nations with an essentialmechanism for global cooperation in the study ofthe ocean. The IOC assists governments toaddress their individual and collective ocean andcoastal problems through the sharing ofknowledge, information and technology and

ICG TSUNAMI WARNING FOCAL POINT (TWFP)

7x24 contact person, or other official point ofcontact or address, for rapidly receiving andissuing tsunami event information (such aswarnings). The Tsunami Warning Focal Pointhas the responsibility of notifying the emergencyauthority (civil defense or other designatedagency responsible for public safety) of theevent characteristics (earthquake and/ortsunami), in accordance with the procedures ofthe Tsunami Response Plan. The TsunamiWarning Focal Point receives internationaltsunami warnings from the PTWC, NWPTAC, orother regional warning centres.

ICG TSUNAMI NATIONAL CONTACT (TNC)

The person designated by an ICG Member Stategovernment to represent his/her country in thecoordination of international tsunami warningand mitigation activities. The person is part ofthe main stakeholders of the national tsunamiwarning and mitigation system programme. Theperson may be the Tsunami Warning FocalPoint, from the national disaster managementorganization, from a technical or scientificinstitution, or from another agency with tsunamiwarning and mitigation responsibilities.

ITIC International Tsunami Information Centre. ITICwas established in November 1965 by the IOC ofUNESCO. In 1968, the IOC first convened theICG/ITSU to coordinate tsunami warning andmitigation activities in the Pacific. The ITIC servesas the PTWS Secretariat. Additionally, the ITICprovides technical and capacity buildingassistance to Member States for the globalestablishment of tsunami warning and mitigationsystems in the Indian and Atlantic Oceans, theCaribbean and Mediterranean Seas, and otheroceans and marginal seas. In the Pacific, the ITICspecifically monitors and recommendsimprovements to the PTWS, coordinates tsunamitechnology transfer among Member Statesinterested in establishing regional and nationaltsunami warning systems, acts as a clearinghousefor risk assessment and mitigation activities, andserves as a resource for the development,publication, and distribution of tsunami educationand preparedness materials. (http://www.tsunamiwave.info)

IUGG International Union of Geodesy and Geophysics.The IUGG is a non-governmental, scientificorganization established in 1919, dedicated topromoting and coordinating studies of the Earthand its environment in space. The IUGG TsunamiCommission, established in 1960, is aninternational group of scientists concerned withvarious aspects of tsunamis, including animproved understanding of the dynamics ofgeneration, propagation, and coastal runup oftsunami, as well as their consequences to society.(http://iugg.org)

JMA Japan Meteorological Agency. JMA established atsunami warning service in 1952. JMA now servesas a National Tsunami Warning System thatcontinuously monitors 24 hours-a-day all seismicactivity in Japan, and issues timely informationconcerning earthquakes and tsunamis. In 2005,t h e J M A b e g a n o p e r a t i o n s o f t h e

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through the coordination of national programmes.(http://ioc.unesco.org/iocweb/index.php)

MASTER PLAN

The principal long-term guide for improving theTWS. The Plan provides a summary of the basicelements which comprise the TWS, a descriptionof its existing components, and an outline of theactivities, data sets, methods, and procedures thatneed to be improved in order to reduce tsunamirisk. The first edition of the ICG/PTWS MasterPlan was released in 1989. The second editionwas released in 1999. (http://ioc3.unesco.org/itic/categories.php?category_no=64)

Northwest Pacific Tsunami Advisory Center(NWPTAC). The NWPTAC providessupplementary tsunami information for events inand around Japan and the northwest Pacific inclose coordination with the PTWC. (http://www.jma.go.jp/jma)

OCEAN-WIDE TSUNAMI WARNING

A warning issued to all participants after there isconfirmation of tsunami waves capable of causingdestruction beyond the local area. Ocean-WideTsunami Warnings contain estimated tsunamiarrival times (ETAs) at all Forecast Points.Ocean-Wide Tsunami Warning Bulletins alsonormally carry information on selected waveheights and other wave reports. The Warning willbe cancelled when it is determined that thetsunami threat is over. As local conditions cancause wide variations in tsunami wave action, theall-clear determination should be made by thelocal action agencies and not the TWC. In general,after receipt of a Tsunami Warning, actionagencies can assume all-clear status when theirarea is free from damaging waves for at least twohours, unless additional ETAs have beenannounced by the TWC (for example for asignificant aftershock) or local conditions, that mayinclude continued seiching or particularly strongcurrents in channels and harbours, warrant thecontinuation of the Tsunami Warning status. SAMPLE: Pacific-Wide Tsunami Warning (initial) TSUNAMI BULLETIN NUMBER 004 PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS ISSUED AT 2119Z 25 FEB 2005

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THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA. ... A PACIFIC-WIDE TSUNAMI WARNING IS IN EFFECT ... THIS WARNING IS FOR ALL COASTAL AREAS ANDISLANDS IN THE PACIFIC. AN EARTHQUAKE HAS OCCURRED WITH THESEPRELIMINARY PARAMETERS ORIGIN TIME - 1804Z 25 FEB 2005 COORDINATES - 52.3 NORTH 160.7 EAST LOCATION - OFF EAST COAST OF KAMCHATKA MAGNITUDE - 8.8 MEASUREMENTS OR REPORTS OF TSUNAMI WAVE ACTIVITY GAUGE LOCATION LAT LON TIME AMPL PER ---------------------------------------------------------------------- NIKISKI 60.7N 151.4W 0057Z 0.52M **MIN SEVERO KURILSK 50.7N 156.1E 2042Z 0.12M 64MIN TIME - TIME OF THE MEASUREMENT AMPL - AMPLITUDE IN METERS FROM MIDDLE TO CREST OR MIDDLE TO TROUGH OR HALF OF THE CREST TO TROUGH PER - PERIOD OF TIME FROM ONE WAVE CREST TO THE NEXT EVALUATION SEA LEVEL READINGS CONFIRM THAT A TSUNAMI HASBEEN GENERATED WHICH COULD CAUSE WIDESPREADDAMAGE TO COASTS AND ISLANDS IN The PACIFIC.AUTHORITIES SHOULD TAKE APPROPRIATE ACTION INRESPONSE TO THIS THREAT. THIS CENTER WILLCONTINUE TO MONITOR SEA LEVEL DATA TODETERMINE THE EXTENT AND SEVERITY OF THETHREAT. A TSUNAMI IS A SERIES OF WAVES AND THE FIRSTWAVE MAY NOT BE THE LARGEST. TSUNAMI WAVEHEIGHTS CANNOT BE PREDICTED AND CAN VARYSIGNIFICANTLY ALONG A COAST DUE TO LOCALEFFECTS. THE TIME FROM ONE TSUNAMI WAVE TO THENEXT CAN BE FIVE MINUTES TO AN HOUR, AND THETHREAT CAN CONTINUE FOR MANY HOURS ASMULTIPLE WAVES ARRIVE. FOR ALL AREAS - WHEN NO MAJOR WAVES AREOBSERVED FOR TWO HOURS AFTER THE ESTIMATEDTIME OF ARRIVAL OR DAMAGING WAVES HAVE NOTOCCURRED FOR AT LEAST TWO HOURS THEN LOCALAUTHORITIES CAN ASSUME THE THREAT IS PASSED.DANGER TO BOATS AND COASTAL STRUCTURES CANCONTINUE FOR SEVERAL HOURS DUE TO RAPIDCURRENTS. AS LOCAL CONDITIONS CAN CAUSE AWIDE VARIATION IN TSUNAMI WAVE ACTION THE ALLCLEAR DETERMINATION MUST BE MADE BY LOCALAUTHORITIES.

BULLETINS WILL BE ISSUED HOURLY OR SOONER IF CONDITIONS WARRANT.

PTWC Established in 1949, the Richard H. HagemeyerPacific Tsunami Warning Center (PTWC) in EwaBeach, Hawaii, acts as the operationalheadquarters for the PTWS and works closely withother sub-regional and national centres inmonitoring and evaluating potentially tsunamigenicearthquakes. It provides international warnings forteletsunamis to countries in the Pacific Basin aswell as to Hawaii and all other US interests in thePacific outside of Alaska. The West Coast andAlaska Tsunami Warning Center (WC/ATWC)provides services to the Gulf of Mexico andAtlantic coasts of the USA, and to the west andeast coasts of Canada. PTWC is also the warningcentre for Hawaii's local and regional tsunamis. In2005, the PTWC and JMA began providing interimadvisory services to the Indian Ocean. The PTWCalso assists Puerto Rico and the US Virgin Islandswith advisory information, and the WC/ATWCprovides services to the west and east coasts ofCanada.

PTWC operations area.

PTWC facilities located at Ewa Beach, Hawaii, USA.

The operational objective of the PTWC is to detectand locate major earthquakes in the region, todetermine if tsunamis were generated, and toprovide timely tsunami warnings to nationalauthorities. To achieve this objective, the PTWCcontinuously monitors seismic activity and sealevels, and disseminates information messagesthrough a variety of communications methods.The PTWC and the WC/ATWC are operated bythe US NOAA National Weather Service.(http://www.prh.noaa.gov/ptwc) (http://wcatwc.arh.noaa.gov/)

for tsunami warning. Among the most importantactivities of the PTWS is the detection andlocation of major earthquakes in the Pacific region,the determination of whether they have generatedtsunamis, and the provision of timely and effectivetsunami information and warnings to coastalcommunities in the Pacific to minimize the hazardsof tsunamis, especially to human life and welfare.To achieve this objective requires the nationalparticipation and contribution of many seismic, sealevel, communication, and dissemination facilitiesthroughout the Pacific Region.

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Global seismic network used by PTWC to monitorseismicity.

Sea level network used by PTWC to monitor Pacific sealevels. Circles show coastal sea level stations andtriangles show NOAA DART systems. Colors indicateresponsible agency: PTWC (dark blue), NOAA NationalOcean Service (green), Univ of Hawaii Sea Level Center(red), SHOA (blue green), JMA (pink), Russian Hydromet(brown), Australia National Tidal Center (light blue),WC/ATWC (yellow), NOAA National Data Buoy Center(orange).

PTWS

Pacific Tsunami Warning System. The PTWS isan international programme for coordination oftsunami warning and mitigation activities in thePacific. Administratively, participating nations areorganized under the IOC as the ICG/PTWS withthe ITIC acting as the PTWS Secretariat and thePTWC acting as the operational headquarters

REGIONAL EXPANDING TSUNAMI WATCH/WARNING BULLETIN (RWW)

A message issued initially using only seismicinformation to alert countries of the possibility of atsunami and advise that a tsunami investigation isunderway. In the Pacific, Tsunami Warning statuswill encompass regions having less than threehours until the estimated time of tsunami arrival.Those areas having three to six hours will beplaced in a Watch status. Additional bulletins willbe issued hourly or sooner until either a Pacific-wide tsunami is confirmed or no further tsunamithreat exists. SAMPLE: Expanding Regional Tsunami Warning and Watch (initial) TSUNAMI BULLETIN NUMBER 001 PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS ISSUED AT 1819Z 25 FEB 2005 THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA. ... A TSUNAMI WARNING AND WATCH ARE IN EFFECT ... A TSUNAMI WARNING IS IN EFFECT FOR RUSSIA / JAPAN / MARCUS IS. / MIDWAY IS. / WAKE IS. / N. MARIANAS / MARSHALL IS. / GUAM / HAWAII / JOHNSTON IS. / CHUUK / POHNPEI / TAIWAN / KOSRAE / YAP / PHILIPPINES / BELAU / NAURU / KIRIBATI / SAMOA / AMERICAN SAMOA / FIJI / MEXICO / HONG KONG / NEW CALEDONIA / COOK ISLANDS / FR. POLYNESIA A TSUNAMI WATCH IS IN EFFECT FOR NEW ZEALAND / EL SALVADOR / NICARAGUA

GAUGE LOCATION LAT LON TIME AMPL PER ---------------------------------------------------------------------- NIKISKI 60.7N 151.4W 0057Z 0.52M **MIN SEVERO KURILSK 50.7N 156.1E 2042Z 0.12M 64MIN TIME - TIME OF THE MEASUREMENT AMPL - AMPLITUDE IN METERS FROM MIDDLE TO CREST OR MIDDLE TO TROUGH OR HALF OF THE CREST TO TROUGH PER - PERIOD OF TIME FROM ONE WAVE CREST TO THE NEXT EVALUATION SEA LEVEL READINGS INDICATE A TSUNAMI WASGENERATED. IT MAY HAVE BEEN DESTRUCTIVE ALONGCOASTS NEAR THE EARTHQUAKE EPICENTER. FORTHOSE AREAS WHEN NO MAJOR WAVES AREOBSERVED FOR TWO HOURS AFTER THE ESTIMATEDTIME OF ARRIVAL OR DAMAGING WAVES HAVE NOTOCCURRED FOR AT LEAST TWO HOURS THEN LOCALAUTHORITIES CAN ASSUME THE THREAT IS PASSED.DANGER TO BOATS AND COASTAL STRUCTURES CANCONTINUE FOR SEVERAL HOURS DUE TO RAPIDCURRENTS. AS LOCAL CONDITIONS CAN CAUSE AWIDE VARIATION IN TSUNAMI WAVE ACTION THE ALLCLEAR DETERMINATION MUST BE MADE BY LOCALAUTHORITIES. NO TSUNAMI THREAT EXISTS FOR OTHER COASTALAREAS IN THE PACIFIC ALTHOUGH SOME OTHERAREAS MAY EXPERIENCE SMALL SEA LEVEL CHANGESFOR ALL AREAS THE TSUNAMI WARNING AND TSUNAMIWATCH ARE CANCELLED. THIS WILL BE THE FINAL BULLETIN ISSUED FOR THISEVENT UNLESS ADDITIONAL INFORMATION BECOMESAVAILABLE.

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FOR ALL OTHER PACIFIC AREAS, THIS MESSAGE IS ANADVISORY ONLY. AN EARTHQUAKE HAS OCCURRED WITH THESEPRELIMINARY PARAMETERS ORIGIN TIME - 1804Z 25 FEB 2005 COORDINATES - 52.3 NORTH 160.7 EAST LOCATION - OFF EAST COAST OF KAMCHATKA MAGNITUDE - 8.1 EVALUATION IT IS NOT KNOWN THAT A TSUNAMI WAS GENERATED.THIS WARNING IS BASED ONLY ON THE EARTHQUAKEEVALUATION. AN EARTHQUAKE OF THIS SIZE HAS THEPOTENTIAL TO GENERATE A DESTRUCTIVE TSUNAMITHAT CAN STRIKE COASTLINES NEAR THE EPICENTERWITHIN MINUTES AND MORE DISTANT COASTLINESWITHIN HOURS. AUTHORITIES SHOULD TAKEAPPROPRIATE ACTION IN RESPONSE TO THISPOSSIBILITY. THIS CENTER WILL MONITOR SEA LEVELDATA FROM GAUGES NEAR THE EARTHQUAKE TODETERMINE IF A TSUNAMI WAS GENERATED ANDESTIMATE THE SEVERITY OF THE THREAT. ESTIMATED INITIAL TSUNAMI WAVE ARRIVAL TIMES.ACTUAL ARRIVAL TIMES MAY DIFFER AND THE INITIALWAVE MAY NOT BE THE LARGEST. THE TIME BETWEENSUCCESSIVE TSUNAMI WAVES CAN BE FIVE MINUTESTO ONE HOUR. SAMPLE: Expanding Regional Tsunami Warning and Watch (cancellation) TSUNAMI BULLETIN NUMBER 003 PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS ISSUED AT 2019Z 25 FEB 2005 THIS BULLETIN IS FOR ALL AREAS OF THE PACIFICBASIN EXCEPT ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA. ... TSUNAMI WARNING AND WATCH CANCELLATION ... THE TSUNAMI WARNING AND WATCH ARE CANCELLEDFOR ALL COASTAL AREAS AND ISLANDS IN THEPACIFIC. AN EARTHQUAKE HAS OCCURRED WITH THESEPRELIMINARY PARAMETERS ORIGIN TIME - 1804Z 25 FEB 2005 COORDINATES - 52.3 NORTH 160.7 EAST LOCATION - OFF EAST COAST OF KAMCHATKA MAGNITUDE - 8.1 MEASUREMENTS OR REPORTS OF TSUNAMI WAVEACTIVITY

REGIONAL FIXED TSUNAMI WARNING BULLETIN

A message issued initially using only seismicinformation to alert all participants of the possibilityof a tsunami and advise that a tsunamiinvestigation is underway. The area placed in aTsunami Warning status encompasses coastalregions within 1000-km of the earthquakeepicenter. A Regional Fixed Tsunami Warningwill be followed by additional bulletins withoutexpanding the warning area until it is eitherupgraded or is canceled.

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SAMPLE: Fixed Regional Tsunami Warning (initial) TSUNAMI BULLETIN NUMBER 001 PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS ISSUED AT 1819Z 25 FEB 2005 THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON CALIFORNIA. ... A TSUNAMI WARNING IS IN EFFECT ... A TSUNAMI WARNING IS IN EFFECT FOR RUSSIA FOR ALL OTHER PACIFIC AREAS, THIS MESSAGE IS AN ADVISORY ONLY. AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS ORIGIN TIME - 1804Z 25 FEB 2005 COORDINATES - 52.3 NORTH 160.7 EAST LOCATION - OFF EAST COAST OF KAMCHATKA MAGNITUDE - 7.7 EVALUATION IT IS NOT KNOWN THAT A TSUNAMI WAS GENERATED.THIS WARNING IS BASED ONLY ON THE EARTHQUAKEEVALUATION. AN EARTHQUAKE OF THIS SIZE HAS THEPOTENTIAL TO GENERATE A DESTRUCTIVE TSUNAMITHAT CAN STRIKE COASTLINES IN THE REGION NEARTHE EPICENTER WITHIN MINUTES TO HOURS.AUTHORITIES IN THE REGION SHOULD TAKEAPPROPRIATE ACTION IN RESPONSE TO THISPOSSIBILITY. THIS CENTER WILL MONITOR SEA LEVELGAUGES NEAREST THE REGION AND REPORT IF ANYTSUNAMI WAVE ACTIVITY IS OBSERVED. THE WARNINGWILL NOT EXPAND TO OTHER AREAS OF THE PACIFICUNLESS ADDITIONAL DATA ARE RECEIVED TOWARRANT SUCH AN EXPANSION. ESTIMATED INITIAL TSUNAMI WAVE ARRIVAL TIMES.ACTUAL ARRIVAL TIMES MAY DIFFER AND THE INITIALWAVE MAY NOT BE THE LARGEST. THE TIME BETWEENSUCCESSIVE TSUNAMI WAVES CAN BE FIVE MINUTESTO ONE HOUR. LOCATION COORDINATES ARRIVAL TIME ----------------------------------------------------------------------- RUSSIA PETROPAVLOVSK-K 52.9N 158.3E 1926Z 25 FEB UST KAMCHATSK 56.2N 162.5E 1943Z 25 FEB MEDNNY IS 54.6N 167.6E 1946Z 25 FEB SEVERO KURILSK 50.6N 156.3E 2000Z 25 FEB URUP IS 45.9N 150.2E 2031Z 25 FEB BULLETINS WILL BE ISSUED HOURLY OR SOONER IFCONDITIONS WARRANT.

THE TSUNAMI WARNING WILL REMAIN IN EFFECT UNTIL FURTHER NOTICE. SAMPLE: Fixed Regional Tsunami Warning (cancellation) TSUNAMI BULLETIN NUMBER 003 PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS ISSUED AT 2019Z 25 FEB 2005 THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA. ... TSUNAMI WARNING CANCELLATION ... THE TSUNAMI WARNING IS CANCELLED FOR ALL COASTAL AREAS AND ISLANDS IN THE PACIFIC. AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS ORIGIN TIME - 1804Z 25 FEB 2005 COORDINATES - 52.3 NORTH 160.7 EAST LOCATION - OFF EAST COAST OF KAMCHATKA MAGNITUDE - 7.7 MEASUREMENTS OR REPORTS OF TSUNAMI WAVE ACTIVITY GAUGE LOCATION LAT LON TIME AMPL PER ---------------------------------------------------------------------- NIKISKI 60.7N 151.4W 0057Z 0.52M **MIN SEVERO KURILSK 50.7N 156.1E 2042Z 0.12M 64MIN

TSUNAMI BULLETIN BOARD (TBB)

TBB is an ITIC-sponsored e-mail service thatprovides an open, objective scientific forum for theposting and discussion of news and informationrelating to tsunamis and tsunami research. TheITIC provides the service to tsunami researchersand other technical professionals for the purposeof facilitating the widespread dissemination ofinformation on tsunami events, current researchinvestigations, and announcements for upcomingmeetings, publications, and other tsunami-relatedmaterials. All members of the TBB are welcome tocontribute. Messages are immediately broadcastwithout modification. The TBB has been veryuseful for helping to rapidly organize post-tsunamisurveys, for distributing their results, and forplanning tsunami workshops and symposia.Members of the TBB automatically receive thetsunami bulletins issued by the PTWC,WC/ATWC, and JMA.

TSUNAMI INFORMATION BULLETIN (TIB)

TWC message product advising the occurrence ofa major earthquake wth an evaluation that there iseither: a) no widespread tsunami threat but thesmall possibility of a local tsunami or b) there is notsunami threat at all hat indicates there is notsunami threat. SAMPLE: Tsunami Information Bulletin (shallow undersea event) TSUNAMI BULLETIN NUMBER 001 PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS ISSUED AT 1819Z 25 FEB 2005 THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA. ... TSUNAMI INFORMATION BULLETIN ... THIS MESSAGE IS FOR INFORMATION ONLY. THERE IS NO TSUNAMI WARNING OR WATCH IN EFFECT. AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS ORIGIN TIME - 1804Z 25 FEB 2005 COORDINATES - 52.3 NORTH 160.7 EAST LOCATION - OFF EAST COAST OF KAMCHATKA MAGNITUDE - 6.7 EVALUATION NO DESTRUCTIVE PACIFIC-WIDE TSUNAMI THREATEXISTS BASED ON HISTORICAL EARTHQUAKE ANDTSUNAMI DATA. HOWEVER - EARTHQUAKES OF THIS SIZE SOMETIMESGENERATE LOCAL TSUNAMIS THAT CAN BEDESTRUCTIVE ALONG COASTS LOCATED WITHIN AHUNDRED KILOMETERS OF THE EARTHQUAKEEPICENTER. AUTHORITIES IN THE REGION OF THEEPICENTER SHOULD BE AWARE OF THIS POSSIBILITYAND TAKE APPROPRIATE ACTION. THIS WILL BE THE ONLY BULLETIN ISSUED FOR THISEVENT UNLESS ADDITIONAL INFORMATION BECOMESAVAILABLE.

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TSUNAMI RESPONSE PLAN (TRP)

The Tsunami Response Plan describes theactions taken to ensure public safety byresponsible agencies after notification by theTsunami Warning Focal Point (TWFP), typicallythe national Tsunami Warning Centre. It includesStandard Operating Procedures and Protocols for

emergency response and action, organizationsand individuals involved and their roles andresponsibilities, contact information, timeline andurgency assigned to action, and means by whichboth ordinary citizens and special needspopulations (physically or mentally handicapped,elderly, transient, and marine populations) will bealerted. For tsunami response, emphasis isplaced on the rapidness, efficiency, conciseness,and clarity of the actions and instructions to thepublic. A Tsunami Response Plan should alsoinclude post-tsunami actions and responsibilitiesfor search and rescue, relief, rehabilitation, andrecovery.

TSUNAMI WARNING CENTRE (TWC)

Centre that issues timely tsunami informationmessages. The messages can be information,watch, or warning messages, and are based onthe available seismological and sea level data asevaluated by the TWC, or on evaluations receivedby the TWC from other monitoring agencies. Themessages are advisory to the official designatedemergency response agencies. Regional TWCmonitor and provide tsunami information toMember States on potential ocean-wide tsunamisusing global data networks, and can often issuemessages within 20 minutes of the earthquake.Local TWC moni tor and provide tsunamiinformation on potential local tsunamis that willstrike within minutes. Local TWC must haveaccess to continuous, real-time, densely-spaced

TSUNAMI WARNING

The highest level of tsunami alert. Warnings areissued by the TWCs due to confirmation of adestructive tsunami wave or the threat of animminent tsunami. Initially the warnings are basedonly on seismic information without tsunamiconfirmation as a means of providing the earliestpossible alert to at-risk populations. Warningsinitially place a restricted area in a condition thatrequires all coastal areas in the region to beprepared for imminent flooding. Subsequent textproducts are issued at least hourly or asconditions warrant to continue, expand, restrict, orend the warning. In the event a tsunami has beenconfirmed which could cause damage at distancesgreater than 1000 km from the epicenter, thewarning may be extended to a larger area.

United Nations Educational, Scientific and CulturalOrganization. Established in 1945, UNESCOp r o m o t e s i n t e r n a t i o n a l c o o p e r a t i o namong its Member States in the fields ofeducation, science, culture and communication.Today, UNESCO works as a laboratory of ideasand standard setter to forge universal agreementson emerging ethical issues. The Organizationalso serves as a clearinghouse that disseminatesand shares information and knowledge, whilehelping Member States to build their human andinstitutional capacities in diverse fields. TheUNESCO Constitution states, “Since wars begin inthe minds of men, it is the minds of men that thedefences of peace must be constructed.”(http://www.unesco.org/bpi)

WDC

World Data Center. The WDC system was createdto archive and distribute data collected from theobservational programs of the 1957-1958International Geophysical Year. Originallyestablished in the United States, Europe, Russia,and Japan, the WDC system has since expandedto other countries and to new scientific disciplines.The WDC system now includes 52 Centers in 12countries. Its holdings include a wide range ofsolar, geophysical, environmental, and humandimensions data. These data cover time scalesranging from seconds to millennia and theyprovide baseline information for research in manydisciplines. Tsunamis are collected by the WDCfor Solid Earth Geophyics. The WDC-SEG is co-located with the USA NOAA National GeophysicalData Center. (http://www.ngdc.noaa.gov/wdc/wdcmain.html)

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Centres (TWCs) based on seismic informationwithout destructive tsunami confirmation. Thewatch is issued as a means of alerting the affectedpopulations located, for example, 1 to 3 hourstsunami travel time beyond the warned area.Subsequent text products are issued at leasthourly to expand the watch and warning area,upgrade all areas to a warning, or end the watchand warning. A Tsunami Watch may be includedin the text of the message that disseminates aTsunami Warning.

TSUNAMI WARNING CENTRE PRODUCTS

Tsunami Warning Centres issue four basic typesof messages: 1) information bulletins when alarge earthquake has occurred but there is little orno tsunami threat; 2) regional watch and warningbulletins when there is a potential threat adestructive tsunami; 3) ocean-wide warningbulletin when there is confirmation of tsunamiwaves capable of widespread tsunami destructionbeyond the local area; and 4) tsunamicommunication test messages to regularlyexercise the system. Initial evaluations andmessages are based only on the faster arrivingseismic information, specifically earthquakelocation, magnitude, and depth. If a tsunami threatis possible, estimated tsunami wave arrival timesare calculated and sea level records are examinedto confirm whether a tsunami has been generated.Watch and Warning bulletins are updated hourlyuntil the threat is gone. In the Pacific, the types ofmessages issued by the PTWC include a Pacific-Wide Tsunami Warning Bulletin, RegionalExpanding Tsunami Warning and Watch Bulletin,Regional Fixed Tsunami Warning Bulletin, andTsunami Information Bulletin, and TsunamiCommunication Test Dummy Message.

UNESCO

TSUNAMI WATCH

The second highest level of tsunami alert.Watches are issued by the Tsunami Warning

data networks in order to characterize theearthquakes within seconds and issue a warningwithin minutes. An example of a Regional Tsunami WarningCentre is the Pacific Tsunami Warning Centerwhich provides international tsunami warnings tothe Pacific. After the 26 December 2005 tsunami,the PTWC and JMA has acted as an InterimRegional TWC for the Indian Ocean. Examples of sub-regional TWC are the NWPTACoperated by the Japan JMA, WC/ATWC operatedby the USA NOAA NWS, and CPPT operated byFrance. These centres, along with Russia andChile, also act as national TWC providing localtsunami warnings for their countries.

GENERAL

Atwater, Brian F., et.al., Surviving a tsunami -Lessons from Chile, Hawaii, and Japan. USGSCircular 1187. [Washington DC]: GPO, rev 2005. Bernard, E.N., ed., Developing tsunami-resilientcommunities: The National Tsunami HazardMitigation Program, Dorchedt: Springer, 2005. Dudley, M. and M. Lee, Tsunami! 2nd Ed., Honolulu:University of Hawaii Press, 1998. Iida, K., Catalog of tsunamis in Japan and itsneighboring countries. Special Report, Yashigasa,Yakusa-cho, Toyota-shi: Aichi Institute ofTechnology, 1984. Tsunami Newsletter, IOC International TsunamiInformation Centre, Honolulu,1965 to present. UNESCO-IOC. IUGG/IOC TIME Project: Numericalmethod of tsunami simulation with the leap-frogscheme. IOC Manuals and Guides No. 35. Paris,UNESCO, 1997. UNESCO-IOC. Master plan for the Tsunami WarningSystem in the Pacific. Second Edition. IOCInformation document No. 1124. Paris, UNESCO,1999. In English; Spanish, French and Russianversion also online. UNESCO-IOC International Tsunami InformationCentre. Tsunami: The Great Waves. IOC Brochure2005. Paris, UNESCO, 2005. In English; Spanishand French earlier version also online. UNESCO-IOC International Tsunami InformationCentre. Tsunami Glossary. IOC Informationdocument No. 1121. Paris, UNESCO, 2006. Earlierrevision in Spanish and French. UNESCO-IOC. Tsunami Glossary: A glossary ofterms and acronyms used in the tsunami literature.IOC Technical Series No. 37. Paris, UNESCO, 1991. UNESCO-IOC International Tsunami InformationCentre. Tsunami Warning!, IOC Brochure 2005.Paris, UNESCO, 2005.

EVENT CATALOGUES

Berninghausen, W.H., Tsunamis and seismicseiches reported from regions adjacent to the IndianOcean. Bulletin of the Seismological Society ofAmerica, Feb.1966; 56(1):69-74. Berninghausen, W.H., Tsunamis and seismicseiches reported from the Western North andAtlantic and the coastal waters of NorthwesternEurope. Informal Report No. 68-05, Washington DC:Naval Oceanographic Office, 1968. Berninghausen, W.H., Tsunamis reported from thewest coast of South America, 1562-1960. Bull.Seismol. Soc. Amer., 52, 915-921, 1962. Berninghausen, W. H., Tsunamis and seismicseiches reported from the eastern Atlantic south ofthe Bay of Biscay. Bull. Seismol. Soc. Amer., 54,439-442, 1964. Dunbar, P.K., P. A. Lockridge, and L. S. Whiteside,Catalogue of Significant Earthquakes 2150BC1991AD. US Department of Commerce,NOAA, National Geophysical Data Center, Boulder,USA, World Data Center A for Solid EarthGeophysics Reports SE-49, 320 pp, 1992. Everingham, I.B., Preliminary Catalogue ofTsunamis for the New Guinea I Solomon IslandRegion 1768-1972. Bureau of Mineral Resources,Canberra, Australia, Report 180, 78 pp, 1977. Iida, K., D. Cox, and G. Pararas-Carayannis,Preliminary catalog of tsunamis occurring in thePacific Ocean. Data Report No. 5, Hawaii Institute ofGeophysics, HIG-67-10. Honolulu: University ofHawaii,re-issued1972. URL:http://www.soest.hawaii.edu/Library/Tsunami%20Reports/Iida_et_al.pdf

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UNESCO-IOC. Post-tsunami survey field guide.First Edition. IOC Manuals and Guides No. 37.Paris, UNESCO, 1998. Versions in Russian, Frenchand Spanish. English and Spanish versions availableonline through ITIC Web Site.

TECHNICAL

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Pararas-Carayannis, G., Catalogue of Tsunamis inthe Hawaiian Islands. US Department of Commerce,NOAA National Geophysical Center, Boulder, USA,World Data Center A for Solid Earth GeophysicsPublication, 94 pp, 1969. Lander, J.F, P.A. Lockridge, and M.J. Kozuch,Tsunamis affecting the West Coast of the UnitedStates 1806-1992. US Department of Commerce,NOAA, National Geophysical Data Center, Boulder,USA, NGDC Key to Geophysical RecordsDocumentation KGRD-29. December 1993, 242 pp,1993. Lander, J., and P. Lockridge, United StatesTsunamis (including United States Possessions)1690-1988. Publication 41-2, Boulder: NationalGeophysical Data Center, 1989. Lockridge, P.A. and R. H. Smith, 1984 : Map ofTsunamis in the Pacific Basin, 1900-1983. Scale1:17,000,000. US NOAA National Geophysical DataCenter World Data Centre A For Solid EarthGeophysics and Circum-Pacific Council for Energyand Minteralo Resources Map Project. Molina, E.e (Seccion de Sismologia, INSIVUMEH,Guatemala). Tsunami catalogue for Central America1539-1996 [Report]. Reduction of natural disastersin Central America. Universitas Bergensis TechnicalReport no. II 1-04, Bergen, Norway: Institute of SolidEarth Physics, University of Bergen; 1997. O'Loughlin, K.F. and J.F. Lander, Caribbeantsunamis: A 500-year history from 1498-1998,Advances in Natural and Technological HazardsResearch; v. 20 Boston, MA: Kluwer AcademicPublishers; 2003. Soloviev, S.L., et al., Tsunamis in the MediterraneanSea 2000 BC-2000AD. Advances in Natural andTechnological Hazards Research, Vol. 13,Dordrecht: Kluwer Academic Publishers, 2000. Soloviev, S.L., and C. N. Go, A catalogue oftsunamis on the western shore of the Pacific Ocean.Academy of Sciences of the USSR, NaukaPublishing House, Moscow, 310 p. [CanadianTranslation of Fisheries and Aquatic Sciences No.5077, 1984, translation available from CanadaInstitute for Scientific and Technical Information,National Research Council, Ottawa, Ontario, CanadaK1A OS2, 447 p., 1974]

Abe, K., Size of great earthquakes 1837-1974inferred from tsunami data, J. Geophys. Res, 84,1561-1568, 1979. Abe, Katsuyuki, A new scale of tsunami magnitude,Mt. in Tsunamis: Their science and engineering, Iidaand Iwasaki, eds., Tokyo: Terra Scientific PublishingCompany; 1983, pp. 91-101. Ambraseys, N.N., Data for the investigation of theseismic sea-waves in the Eastern Mediterranean,Bulletin of the Seismological Society of America,52:4 (Oct 1962), pp. 895-913. Dmowska, R. and B. Saltzman, eds., Tsunamigenicearthquakes and their consequences. Advances inGeophysics, Vol. 39, San Diego: Academic Press,1998. European Commission. Directorate General forScience, Research and Development, UNESCO andCommissariatà a l'Energie Atomique (CEA),International Conference on Tsunamis, 26-28 May,1998. France: CEA, [1998]. Hatori, T., Relation between tsunami magnitude andwave energy, Bull. Earthquake Res. Inst. Univ.Tokyo, 54, 531-541 (in Japanese with Englishabstract), 1979. Hatori, T., Classification of tsunami magnitude scale,Bull. Earthquake Res. Inst. Univ. Tokyo, 61, 503-515(in Japanese with English abstract), 1986.

Soloviev, S.L., and C. N. Go, A catalogue oftsunamis on the eastern shore of the Pacific Ocean.Academy of Sciences of the USSR, NaukaPublishing House, Moscow, 204 p. [CanadianTranslation of Fisheries and Aquatic Sciences No.5078, 1984, translation available from CanadaInstitute for Scientific and Technical Information,National Research Council, Ottawa, Ontario, CanadaK1A OS2, 293 p., 1975] Soloviev, S.L., C. Go, and C. S. Kim, Catalogue ofTsunamis in the Pacific 1969-1982, Results ofResearches on the International GeophysicalProjects. Moscow: Academy of Sciences of theUSSR, 1992. Tsunami Laboratory, ICMMG SD RAS, Novosibirsk,Russia, ITDB/WLD (2005) Integrated TsunamiDatabase for the World Ocean, Version 5.15 of July31, 2005, CD-ROM.

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Iida, K. and T. Iwasaki, eds., Tsunamis: Theirscience and engineering, Proceedings of theInternational Tsunami Symposium (1981), Tokyo:Terra Scientific, 1983. Kanamori, H., “Mechanism of tsunami earthquakes,”Phys. Earth Planet. Inter., 6, pp. 346-359, 1972. Keating, B., Waythomas, C., and A. Dawson, eds.,Landslides and Tsunamis. Pageoph TopicalVolumes, Basel: Birhäuser Verlag, 2000. Mader, C., Numerical modeling of water waves, 2nded. Boca Raton, FL: CRC Press, 2004. Papadopoulus, G., and F. Imamura, “A proposal fora new tsunami intensity scale,” InternationalTsunami Symposium Proceedings, Session 5,Number 5-1, Seattle, 2001. Satake, K., ed., Tsunamis: Case studies and recentdevelopments. Dordrecht: Springer, 2005. Satake, K. and F. Imamura, eds., Tsunamis 1992-1994: Their generation, dynamics, and hazard,Pageoph Topical Volumes. Basel: Birhäuser Verlag,1995. Sauber, J. and R. Dmowska, Seismogenic andtsunamigenic processes in shallow subductionzones. Pageoph Topical Volumes, Basel: BirhäuserVerlag, 1999. Shuto, N., “Tsunami intensity and disasters,” inTsunamis in the World edited by S. Tinti, Dordrecht:Kluwer Academic Publishers, pp. 197-216, 1993. Sieberg, A., Erdbebenkunde, Jena: Fischer, 1923.(Sieberg’s scale, pp. 102-104.) Soloviev, S.L., “Recurrence of earthquakes andtsunamis in the Pacific Ocean,” in Tsunamis in thePacific Ocean, edited by W. M. Adams, Honolulu:East-West Center Press, pp. 149-164, 1970. Soloviev, S.L., “Recurrence of earthquakes andtsunamis in the Pacific Ocean,” Volny Tsunami(Trudy SahkNII, Issue 29), Yuzhno-Sakhalinsk, pp.7-46, 1972 (in Russian). Tinti, S., ed., Tsunamis in the World : FifteenthInternational Tsunami Symposium, 1991, Advancesin Natural and Technological Hazards Research,Vol. 1. Dordrecht: Kluwer Academic Publishers,1993.

TEXTBOOKS AND TEACHERS GUIDEBOOKS (in English and Spanish)

Pre-elementary school: Earthquakes and tsunamisChile: SHOA/IOC/ITIC, 1996. Revised 2003 inSpanish. 2-4 Grade: I invite you to know the earth I. Chile:SHOA/IOC/ITIC, 1997. 5-8 Grade: I invite you to know the earth II. Chile:SHOA/IOC/ITIC, 1997. High School: Earthquakes and tsunamis. Chile:SHOA/IOC/ITIC, 1997.

Tsuchiya, Y. and N. Shuto, eds., Tsunami: Progressin prediction, disaster prevention and warning.Advances in Natural and Technological HazardsResearch, Vol. 4. Dordrecht: Kluwer AcademicPublishers, 1995. Yeh, H., Liu, P., and C. Synolakis, Long-wave runupmodels, Singapore: World Scientific, 1996.

Air-coupled tsunami 2 Arrival time 16 Atmospheric tsunami 2 Breaker 7 Breakwater 7 Communications Plan 24 for the Tsunami Warning System Cotidal 21 Crest length 16 Deep-ocean tsunami detection 21 system (DART) Drop 16 Eddy 7 Elapsed time 16 Estimated time of arrival (ETA) 8 Evacuation map 8 Forecast Point 24 GLOOS 24 GOOS 24 GTS 24 Historical tsunami 2 Historical tsunami data 8 ICG 24 ICG/CARIBE-EWS 25 ICG/IOTWS 25 ICG/ITSU 25 ICG/NEAMTWS 25 ICG/PTWS 25 ICG Tsunami Warning Focal Point (TWFP) 25 ICG Tsunami National Contact (TNC) 25 Initial rise 16 Intensity 16 Inundation 16 Inundation (maximum) 16 Inundation area 16 Inundation line 17 IOC 25 ITIC 26 IUGG 26 JMA 26 Leading wave 17 Local tsunami 2 Low water 21

Tsunami 6Tsunami amplitude 19Tsunami bore 9Tsunami Bulletin Board (TBB) 30Tsunami damage 9Tsunami dispersion 10Tsunami earthquake 6Tsunami edge wave 10Tsunami forerunner 10Tsunami generation 10Tsunami generation theory 11Tsunami hazard 11Tsunami hazard assessment 11Tsunami impact 11Tsunami Information Bulletin (TIB) 31Tsunami intensity 20Tsunami magnitude 20Tsunami numerical modelling 12Tsunami observation 13Tsunami period 20Tsunami period (dominant) 20Tsunami preparedness 13Tsunami propagation 14Tsunami resonance 14Tsunami Response Plan (TRP) 31Tsunami risk 14Tsunami sediments 6Tsunami simulation 14Tsunami source 15Tsunami velocity or shallow 15 water velocity Tsunami Warning 31Tsunami Warning Centre (TWC) 31Tsunami Warning Centre Products 32Tsunami Watch 32Tsunami wave length 20Tsunami zonation 15Tsunamic 15Tsunamigenic 15UNESCO 32Water level (maximum) 20Wave crest 20Wave trough 20WDC 32

Magnitude 17 Maremoto 2 Mareogram 21 Mareograph 21 Marigram 21 Master Plan 26 Mean height 17 Mean sea level 21 Microtsunami 2 Ocean-wide tsunami 2 Ocean-wide tsunami warning 26 Overflow 17 Paleotsunami 2 Post-tsunami survey 17 Probable maximum water level 22 PTWC 27 PTWS 28 Recession 18 Reference sea level 22 Refraction diagrams 22 Regional tsunami 3 Regional Expanding Tsunami 28 Watch/Warning Bulletin (RWW) Regional Fixed Tsunami 29 Warning Bulletin Rise 18 Runup 18 Runup distribution 18 Sea level 22 Sea level station 22 Seiche 8 Seismic sea wave 8 Sieberg tsunami intensity scale 18 Significant wave height 19 Spreading 19 Subsidence (uplift) 19 Teletsunami or distant tsunami 4 Tidal wave 23 Tide 23 Tide amplitude 23 Tide gauge 23 Tide station 23 Travel time 8 Travel time map 8 Tsunameter 23

Located in Honolulu, the International Tsunami Information Centre (ITIC) was established on 12 November 1965 by theIntergovernmental Oceanographic Commission (IOC) of the United Nationas Educational, Scientific, and Cultural Organisation(UNESCO). The first session of the International Coordination Group for the Tsunami Warning System in the Pacific (ITSU) convened in1968. In 2005, the ITSU was renamed as the Intergovernmental Coordination Group for the Pacific Tsunami Warning and MitigationSystem (ICG/PTWS) to emphasize the comprehensive nature of risk reduction. The ITIC thanks the following scientists for their assistance and helpful review of this document: Fumihiko Imamura, Modesto Ortiz,Kenji Satake, François Schindele, Fred Stephenson, Costas Synolakis, and Masahiro Yamamoto.

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737 Bishop Street Suite 2200Honolulu, Hawaii 96813-3213, U.S.A.

http://www.tsunamiwave.info

INTERNATIONAL TSUNAMI INFORMATION CENTRE (ITIC) Phone: <1> 808-532-6422

Fax: <1> 808-532-5576E-mail: itic.tsunami@noaa.gov

Intergovernmental Oceanographic Commission (IOC) United Nations Educational, Scientific and Cultural Organization (UNESCO) 1, rue Miollis 75 735 Paris Cedex 15 France Tel : +33 1 45 68 39 83 Fax : +33 1 45 68 58 12 http://ioc.unesco.org

Intergovernmental Oceanographic Commission

International Tsunami Information Centre