project azure - honduras

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Seismic Hazard Assessment

HONDURAS

PROJECT ZURE

Presented by:

David Gutirrez Rivera

101082

June/2013

NHRE- Natural Hazards and Risks in Structural Engineering


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Project Azure Seismic Hazard Assessment HONDURAS

CONTENTS

Page

INTRODUCTION -------------------------------------------------------------------------------- 2

1) SITE DESCRIPTION ---------------------------------------------------------------- 3a) Main Cities (Reference Sites)------------------------------------------------- 5

b) Topography ------------------------------------------------------------------------ 6c) Geology ----------------------------------------------------------------------------- 7d) Subsoil Conditions --------------------------------------------------------------- 8

2) REGION TECTONIC AND SEISMICITY ---------------------------------------- 9a) Tectonic Plates -------------------------------------------------------------------- 9b) Faults -------------------------------------------------------------------------------- 10c) Seismicity --------------------------------------------------------------------------- 11d) Catalog Completeness Analysis ---------------------------------------------- 13e) Seismic Sources Classification ----------------------------------------------- 14

3) SEISMIC HAZARD ASSESSMENT---------------------------------------------- 15a) Sources Seismicity (Gutenberg-Richter) ----------------------------------- 16

b) Ground Motion Prediction Equation (Attenuation Relation) ----------- 18c) Probability of Exceedance ----------------------------------------------------- 20

4) ELASTIC RESPONSE SPECTRA------------------------------------------------ 22a) Earthquake Time Histories----------------------------------------------------- 22b) Site Specific Response Spectra ---------------------------------------------- 26c) Recommended Design Spectra ---------------------------------------------- 28

5) COMPARISONS WITH EURO-CODE------------------------------------------ 306) COMPARISONS WITH NATIONAL CODE------------------------------------ 33

REFERENCES ----------------------------------------------------------------------------------- 35


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INTRODUCTION

This study consists in the development of ground prediction models and seismic hazard

assessment of the region of Honduras. With the collected data from Honduras and

neighboring countries, regional aspects and seismic related parameters some ground

prediction models are developed, like the attenuation relation, with which we are able to

predict ground motion in a site. With this we have developed a seismic hazard assessment of

the region, for 5 sites in Honduras. Making use of earthquakes time histories from the region

weve obtained as a result response spectra for each one of the sites, with which we havecome up with a recommended design spectra for the Country. Finally we compare this with

the National Code and the EuroCode and give some conclusions about the results obtained.


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SITE DESCRIPTION

Honduras is a country situated inCentral America,it borders theCaribbean Sea on the north

coast and the Pacific Ocean on the south through theGulf of Fonseca.It mostly lies between

latitudes13 and17N,and longitudes83 and90W.Guatemala lies to the west,Nicaragua

south east and El Salvador to the south west. It is the second largest Central American

republic. This triangular-shaped country has a total area of just over 110,000 km2. Honduras

controls a number of islands as part of its offshore territories. In the Caribbean Sea, the

islands of Roatn (Isla de Roatn), Utila, and Guanaja together form Islas de la Baha (Bay

Islands), one of the eighteen departments into which Honduras is divided.Roatn,the largest

of the three islands, is fifty kilometers long by five kilometers wide.

Honduras is divided into 18departments,listed in the table below:

Department Department capital Population (2001) Area (km2)

1. Atlntida La Ceiba 344,099 4,251

2. Choluteca Choluteca 390,805 4,211

3. Coln Trujillo

246,708 8,8754. Comayagua Comayagua 352,881 5,196

5. Copn Santa Rosa de Copn 288,766 3,203

6. Corts San Pedro Sula 1,202,510 3,954

7. El Paraso Yuscarn 350,054 7,218

8. Francisco Morazn Tegucigalpa 1,180,676 7,946

9. Gracias a Dios Puerto Lempira 67,384 16,630

10. Intibuc La Esperanza 179,862 3,072

11. Islas de la Baha Roatn 38,073 261

12. La Paz La Paz 156,560 2,331

13. Lempira Gracias 250,067 4,290

14. Ocotepeque Nueva Ocotepeque 108,029 1,680

15. Olancho Juticalpa 419,561 24,351

16. Santa Brbara Santa Brbara 342,054 5,115

17. Valle Nacaome 151,841 1,56518. Yoro Yoro 465,414 7,939
http://en.wikipedia.org/wiki/Central_Americahttp://en.wikipedia.org/wiki/Caribbean_Seahttp://en.wikipedia.org/wiki/Gulf_of_Fonsecahttp://en.wikipedia.org/wiki/13th_parallel_northhttp://en.wikipedia.org/wiki/17th_parallel_northhttp://en.wikipedia.org/wiki/83rd_meridian_westhttp://en.wikipedia.org/wiki/90th_meridian_westhttp://en.wikipedia.org/wiki/Guatemalahttp://en.wikipedia.org/wiki/Nicaraguahttp://en.wikipedia.org/wiki/El_Salvadorhttp://en.wikipedia.org/wiki/Islas_de_la_Bah%C3%ADahttp://en.wikipedia.org/wiki/Roat%C3%A1nhttp://en.wikipedia.org/wiki/Departments_of_Hondurashttp://en.wikipedia.org/wiki/Atl%C3%A1ntida_(department)http://en.wikipedia.org/wiki/Atl%C3%A1ntida_(department)http://en.wikipedia.org/wiki/La_Ceibahttp://en.wikipedia.org/wiki/La_Ceibahttp://en.wikipedia.org/wiki/Choluteca_(department)http://en.wikipedia.org/wiki/Choluteca_(department)http://en.wikipedia.org/wiki/Choluteca,_Cholutecahttp://en.wikipedia.org/wiki/Choluteca,_Cholutecahttp://en.wikipedia.org/wiki/Col%C3%B3n_(department)http://en.wikipedia.org/wiki/Trujillo,_Col%C3%B3nhttp://en.wikipedia.org/wiki/Trujillo,_Col%C3%B3nhttp://en.wikipedia.org/wiki/Comayagua_(department)http://en.wikipedia.org/wiki/Comayagua_(department)http://en.wikipedia.org/wiki/Comayaguahttp://en.wikipedia.org/wiki/Comayaguahttp://en.wikipedia.org/wiki/Cop%C3%A1n_(department)http://en.wikipedia.org/wiki/Santa_Rosa_de_Cop%C3%A1nhttp://en.wikipedia.org/wiki/Santa_Rosa_de_Cop%C3%A1nhttp://en.wikipedia.org/wiki/Cort%C3%A9s_(department)http://en.wikipedia.org/wiki/San_Pedro_Sulahttp://en.wikipedia.org/wiki/San_Pedro_Sulahttp://en.wikipedia.org/wiki/El_Para%C3%ADso_(department)http://en.wikipedia.org/wiki/El_Para%C3%ADso_(department)http://en.wikipedia.org/wiki/Yuscar%C3%A1nhttp://en.wikipedia.org/wiki/Francisco_Moraz%C3%A1n_(department)http://en.wikipedia.org/wiki/Tegucigalpahttp://en.wikipedia.org/wiki/Tegucigalpahttp://en.wikipedia.org/wiki/Gracias_a_Dios_(department)http://en.wikipedia.org/wiki/Gracias_a_Dios_(department)http://en.wikipedia.org/wiki/Puerto_Lempirahttp://en.wikipedia.org/wiki/Puerto_Lempirahttp://en.wikipedia.org/wiki/Intibuc%C3%A1_(department)http://en.wikipedia.org/wiki/Intibuc%C3%A1_(department)http://en.wikipedia.org/wiki/La_Esperanza,_Hondurashttp://en.wikipedia.org/wiki/La_Esperanza,_Hondurashttp://en.wikipedia.org/wiki/Bay_Islands_(department)http://en.wikipedia.org/wiki/Bay_Islands_(department)http://en.wikipedia.org/wiki/Roat%C3%A1nhttp://en.wikipedia.org/wiki/La_Paz_(Honduran_department)http://en.wikipedia.org/wiki/La_Paz,_Hondurashttp://en.wikipedia.org/wiki/Lempira_(department)http://en.wikipedia.org/wiki/Lempira_(department)http://en.wikipedia.org/wiki/Gracias,_Hondurashttp://en.wikipedia.org/wiki/Gracias,_Hondurashttp://en.wikipedia.org/wiki/Ocotepeque_(department)http://en.wikipedia.org/wiki/Ocotepeque_(department)http://en.wikipedia.org/wiki/Nueva_Ocotepequehttp://en.wikipedia.org/wiki/Nueva_Ocotepequehttp://en.wikipedia.org/wiki/Olancho_(department)http://en.wikipedia.org/wiki/Olancho_(department)http://en.wikipedia.org/wiki/Juticalpahttp://en.wikipedia.org/wiki/Juticalpahttp://en.wikipedia.org/wiki/Santa_B%C3%A1rbara_(department)http://en.wikipedia.org/wiki/Santa_B%C3%A1rbara_(department)http://en.wikipedia.org/wiki/Santa_B%C3%A1rbara,_Hondurashttp://en.wikipedia.org/wiki/Santa_B%C3%A1rbara,_Hondurashttp://en.wikipedia.org/wiki/Valle_(department)http://en.wikipedia.org/wiki/Nacaomehttp://en.wikipedia.org/wiki/Yoro_(department)http://en.wikipedia.org/wiki/Yorohttp://en.wikipedia.org/wiki/Yorohttp://en.wikipedia.org/wiki/Yoro_(department)http://en.wikipedia.org/wiki/Nacaomehttp://en.wikipedia.org/wiki/Valle_(department)http://en.wikipedia.org/wiki/Santa_B%C3%A1rbara,_Hondurashttp://en.wikipedia.org/wiki/Santa_B%C3%A1rbara_(department)http://en.wikipedia.org/wiki/Juticalpahttp://en.wikipedia.org/wiki/Olancho_(department)http://en.wikipedia.org/wiki/Nueva_Ocotepequehttp://en.wikipedia.org/wiki/Ocotepeque_(department)http://en.wikipedia.org/wiki/Gracias,_Hondurashttp://en.wikipedia.org/wiki/Lempira_(department)http://en.wikipedia.org/wiki/La_Paz,_Hondurashttp://en.wikipedia.org/wiki/La_Paz_(Honduran_department)http://en.wikipedia.org/wiki/Roat%C3%A1nhttp://en.wikipedia.org/wiki/Bay_Islands_(department)http://en.wikipedia.org/wiki/La_Esperanza,_Hondurashttp://en.wikipedia.org/wiki/Intibuc%C3%A1_(department)http://en.wikipedia.org/wiki/Puerto_Lempirahttp://en.wikipedia.org/wiki/Gracias_a_Dios_(department)http://en.wikipedia.org/wiki/Tegucigalpahttp://en.wikipedia.org/wiki/Francisco_Moraz%C3%A1n_(department)http://en.wikipedia.org/wiki/Yuscar%C3%A1nhttp://en.wikipedia.org/wiki/El_Para%C3%ADso_(department)http://en.wikipedia.org/wiki/San_Pedro_Sulahttp://en.wikipedia.org/wiki/Cort%C3%A9s_(department)http://en.wikipedia.org/wiki/Santa_Rosa_de_Cop%C3%A1nhttp://en.wikipedia.org/wiki/Cop%C3%A1n_(department)http://en.wikipedia.org/wiki/Comayaguahttp://en.wikipedia.org/wiki/Comayagua_(department)http://en.wikipedia.org/wiki/Trujillo,_Col%C3%B3nhttp://en.wikipedia.org/wiki/Col%C3%B3n_(department)http://en.wikipedia.org/wiki/Choluteca,_Cholutecahttp://en.wikipedia.org/wiki/Choluteca_(department)http://en.wikipedia.org/wiki/La_Ceibahttp://en.wikipedia.org/wiki/Atl%C3%A1ntida_(department)http://en.wikipedia.org/wiki/Departments_of_Hondurashttp://en.wikipedia.org/wiki/Roat%C3%A1nhttp://en.wikipedia.org/wiki/Islas_de_la_Bah%C3%ADahttp://en.wikipedia.org/wiki/El_Salvadorhttp://en.wikipedia.org/wiki/Nicaraguahttp://en.wikipedia.org/wiki/Guatemalahttp://en.wikipedia.org/wiki/90th_meridian_westhttp://en.wikipedia.org/wiki/83rd_meridian_westhttp://en.wikipedia.org/wiki/17th_parallel_northhttp://en.wikipedia.org/wiki/13th_parallel_northhttp://en.wikipedia.org/wiki/Gulf_of_Fonsecahttp://en.wikipedia.org/wiki/Caribbean_Seahttp://en.wikipedia.org/wiki/Central_America


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The capital city of Honduras is Tegucigalpa Central District of the department ofFranciscoMorazn. The 18 departments of Honduras are divided into 298 municipalities

(municipalidades).

The population in Honduras is near the 8.0 million. The most populated Departments are:

Corts (1.2 million), Francisco Morazn (1.2 million), Yoro (466,000), Olancho (420,000),Choluteca (391,000) and Comayagua (353,000). The least populated is Gracias a Dios. The

main cities are: Tegucigalpa (894,000 hab.-Distrito Central only-), San Pedro Sula (517,000

hab.), Choloma (160,000 hab.), La Ceiba (140,00 hab.), El Progreso (106,000 hab.), Choluteca,

Comayagua, Puerto Cortes, La Lima and Danli. However, the main metropolitan areas are

Tegucigalpa (1,200,000 hab. -est. 2007-) and San Pedro Sula (900,000 hab. -est. 2007-).
http://en.wikipedia.org/wiki/Tegucigalpahttp://en.wikipedia.org/wiki/Francisco_Moraz%C3%A1nhttp://en.wikipedia.org/wiki/Francisco_Moraz%C3%A1nhttp://en.wikipedia.org/wiki/Hondurashttp://en.wikipedia.org/wiki/Hondurashttp://en.wikipedia.org/wiki/Francisco_Moraz%C3%A1nhttp://en.wikipedia.org/wiki/Francisco_Moraz%C3%A1nhttp://en.wikipedia.org/wiki/Tegucigalpa


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Main Cities (Reference Sites)

Definitely the 2 most important cities in Honduras are Tegucigalpa (the capital of the Country)

and San Pedro Sula, the economically most important city in Honduras. In order to choose

reference sites for this study we defined the following characteristics for each site:

- Population Density

- Importance Aspect

- Seismicity Level

- Location

So taking in to account the above mentioned factors, besides Tegucigalpa and San Pedro Sula,we chose also Choluteca, Roatan and Puerto Cortes. Choluteca has the highest seismicity

zone and also located to the south of the country, near the borders with el Salvador and

Nicaragua, being the closest most important city to the Mesoamerican Trench of the Cocos

Plate. Also has a significant and developing economical importance as a trading place. Sharing

this same economical aspect is Puerto Cortes, the most important port of the country. And

there is Roatan, which importance and activity rely more in tourism, is location is quite

peculiar and so is its seismicity hazard level.

Therefore the Main Cities or Reference Sites chosen for this study are:

1) San Pedro Sula [SPS]

2) Tegucigalpa [TGU]

3) Puerto Cortes [PC]

4) Choluteca

5) Roatan


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Topography

Honduras has three distinct topographical regions: an extensive interior highland area and

two narrow coastal lowlands. The interior, which constitutes approximately 80 percent of

the country's terrain, is mountainous. The larger Caribbean lowlands in the north and the

Pacific lowlands bordering the Gulf of Fonseca are characterized by alluvial plains.

In the west, Honduras's mountains blend into the mountain ranges of Guatemala. The

western mountains have the highest peaks, with thePico Congoln at an elevation of 2,500

meters and the Cerro Las Minas at 2,850 meters. The Honduran border with El Salvador

crosses the peak ofCerro El Pital,the highest point in El Salvador at over 2700 meters. These

mountains are woodland covered with mainly pine forests.

In the east, the mountains merge with those in Nicaragua. Although generally not as high as

the mountains near the Guatemalan border, the eastern ranges possess some high peaks,

such as theMontaa de la Flor at 2,300 meters,El Boquern (Monte El Boquern)at 2,485

meters, andPico Bonito at 2,435 meters.

One of the most prominent features of the interior highlands is a depression that runs from

the Caribbean Sea to the Gulf of Fonseca. This depression splits the country'scordilleras into

eastern and western parts and provides a relatively easy transportation route across the

isthmus. Widest at its northern end near San Pedro Sula, the depression narrows as it follows

the upper course of theRo Humuya.Passing first through Comayagua and then through

narrow passes south of the city, the depression widens again as it runs along the border of El

Salvador into the Gulf of Fonseca.
http://en.wikipedia.org/w/index.php?title=Pico_Congol%C3%B3n&action=edit&redlink=1http://en.wikipedia.org/wiki/Cerro_Las_Minashttp://en.wikipedia.org/wiki/Cerro_El_Pitalhttp://en.wikipedia.org/w/index.php?title=Monta%C3%B1a_de_la_Flor&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=El_Boquer%C3%B3n&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Monte_El_Boquer%C3%B3n&action=edit&redlink=1http://en.wikipedia.org/wiki/Pico_Bonitohttp://en.wikipedia.org/wiki/Cordillerahttp://en.wikipedia.org/w/index.php?title=R%C3%ADo_Humuya&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=R%C3%ADo_Humuya&action=edit&redlink=1http://en.wikipedia.org/wiki/Cordillerahttp://en.wikipedia.org/wiki/Pico_Bonitohttp://en.wikipedia.org/w/index.php?title=Monte_El_Boquer%C3%B3n&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=El_Boquer%C3%B3n&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Monta%C3%B1a_de_la_Flor&action=edit&redlink=1http://en.wikipedia.org/wiki/Cerro_El_Pitalhttp://en.wikipedia.org/wiki/Cerro_Las_Minashttp://en.wikipedia.org/w/index.php?title=Pico_Congol%C3%B3n&action=edit&redlink=1


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Geology

The relative geological youth of the region and its volcanic activity, combined with a tropical

climate, humid, creating a landscape rich in natural hazards. There are four major risks to

consider.

1. The geological activity that originally built this landscape still exists, so the threat of

volcanic eruptions and earthquakes also exist.

2. Earthquakes and associated movements of the crust to the sea can generate

tsunamis or tidal waves, which threaten the coastal areas.

3. The steep topography created by geological activity in the region is susceptible to

landslides. The heavy rains that characterize the region and strong winds thataccompany hurricanes exacerbate this threat.

4. The abundant rainfall in the region may cause erosion of sedimentary deposits of

marine origin (limestone, dolomite, Marla and marble), resulting in the formation of

large holes and tunnels, such subsidence can create significant erosion that threaten

the structures built on them.

Landslides are perhaps the most common destructive natural hazards in Central America. In

reality it is the landslide after an earthquake, flood or hurricane that usually results in the

greatest loss of life and property.


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Faults

The main faults and other seismic sources detected in the Central America region especially

for Honduras are: the Polochic-Motagua fault system, the Guayape fault and the Honduran

Depresion.

The fault system of Polochic-Motagua, in its mainland, consists of three sets of faults with

directions approximately East-West, fromt North to South are: Polochic (Chixoy-Polochic),

Motagua and Jocotn (Jocotn-Chamelecon). The Motagua fault is considered a continuation

of the failure of Swan in the Caribbean, it is the Motagua River basin and its trace is lost in

western Guatemala. Polochic fault has a continuous trace and its clear in most of its length,but its extension to the west, in the State of Chiapas, Mexico, seems to divide into two

branches.

The Guayape fault its aproximately 300 Km long and its to the west of the Motagua fault

and parallel to it in NE-SW direction. This fault is the longest continuous structure within the

territory of Honduras. Activity on this fault is evidenced today only by a very poor seismicity

catalog, despite the clear definition of topographic and thermal presence at several points.

The Honduran Depression located centrally in the Honduran territory going from north to

south from Valley of Sula to the Gulf of Fonseca, is a significantly active seismic zone with

some importan seismic events happening in the past, that can be associated to this area.


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Seismicity

The seismicity in Central America, especially Honduras, is dominated by events produced in

the boundaries of the North American-Caribbean and Cocos-Caribbean plates and an

significant contribution of earthquakes located in the central Honduran depression. The

seismicity in these areas can be classified separating crustal seismicity and deep seismicity

due to the Pacific subduction zone. In their majority the earthquakes affecting the territory

of Honduras are superficial with depths oscillating from 10 to 60km.


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For this study we used a seismic catalog from the years of 1500 to 2001, we show below this

seismic catalog in a map.

For the region of Honduras the maximum moment magnitude recorded has been of Mw= 8.1,

we show below a classification of the Earthquake in the territory of Honduras according toMagnitude.


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Seismic Sources Classification

For purposes of this study we have defined seismo-genetic zones that contributed to the

seismicity of the region of Honduras. These zones have been defined according to the

following characteristics:

- Amount of Earthquake Events

- Magnitudes of Earthquakes

- Direction and Geometry of Faults

This seismo-genetic regions have been considered to have the same seismic origins, therefore

probability of earthquake events are unrelated to each other.

Following the above stated guidelines we have defined 7 seimo-genetic zones, which are

shown in the following map:


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SEISMIC HAZARD ASSESSMENT

The hazard assessment approach for this study will be the probabilistic one (PSHA), which is

the state of the art when it comes to seismic hazard assessment. The general procedure is

shown below:

The Seismo-Genetic Sources have been previously defined, with 7 regions in total. Theregions seismicity will be described by a Gutenberg-Richter plot. This analysis will give us

rates of events, in other words probabilities of earthquake events of specific magnitude.

With the use of the Ground Motion Prediction Equation (GMPE) of our area we can predict

Ground Motion from events occurring at a given distance from the site of interest. This will

give us as a result Peak Ground Acceleration for a given magnitude and distance to the site of

interest.

Combining these two results we can obtain Probability of Exceedance, where we can

determine the probability of an event to exceed a Peak Ground Acceleration in a given periodof time. This is used in codes where definition of appropriate life time of a building is defined,

and therefore a selection of the design peak ground acceleration can be chosen to define the

design response spectra.

Seismo-GeneticSources

Sources Seismicity(Gutenberg-Richter)

Ground MotionPrediction Equation

(Attenuation Relation)

Site Hazard Assessment

(Probability of Exceedance)


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Sources Seismicity (Gutenberg-Richter)

We can describe the seismicity of each region by the use of Gutenberg-Richter plots. These

relations give us the rate of earthquake events of given magnitudes.

y = -0.981x + 4.3001

R = 0.9419-6

-4

-2

0

2

3 4 5 6 7 8

Log

(Rate)

Mw

Gutenberg-Richter Plot

Region 1

Data

Fit

y = -0.9096x + 3.6713

R = 0.9927-5

-4

-3

-2

-10

1

2

3 4 5 6 7 8

Log(Rate)

Mw


Region 2

Data

Fit

y = -1.0651x + 4.5458

R = 0.9543-5

-4

-3

-2

-1

0

1

2

3 4 5 6 7 8

Log(Rate)

Mw


Region 3

Data

Fit


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y = -0.7618x + 2.9386

R = 0.7312-4

-3

-2

-1

0

1

2

3 4 5 6 7 8

Log(Rate)

Mw


Region 4

Data

Fit

y = -0.9773x + 4.4612

R = 0.9633-4

-3

-2

-1

0

1

2

3

3 4 5 6 7 8

Log(Rate)

Mw

Gutenberg-Richter PlotRegion 5

Data

Fit

y = -0.5829x + 2.6529

R = 0.9499-3

-2

-1

0

1

2

3 4 5 6 7 8

Log(Rate)

Mw


Region 6

Data

Fit

y = -0.7902x + 3.997

R = 0.9842-4

-3

-2

-1

0

1

2

3

3 4 5 6 7 8

Log(Rate)

Mw


Region 7

Data

Fit


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Ground Motion Prediction Equation (Attenuation Relation)

For purposes of the ground motion prediction models we used the models proposed by

Ambraseyand Dahle.

AMBRASEY

where f1 and f2

are given by:

Ycan be Peak Ground Acceleration (PGA).

This model is applicable for Ms >=4.0 and Ms


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0.001

0.01

0.1

1

10

1 10 100

PGA-

g

Distance - Km

Attenuation Relation, Ambrasey's (depth=30km)

Mw=5.5

Mw=6.0

Mw=6.5

Mw=7.0

Mw=7.5

Mw=8.0

0.001

0.01

0.1

1

1 10 100

PGA-

g

Distance - Km

Attenuation Relation, Dahle's (depth=30km)

Mw=5.5

Mw=6.0

Mw=6.5

Mw=7.0

Mw=7.5

Mw=8.0


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Probability of Exceedance

Now we proceed with the seismic hazard assessment results, which is presented in with a

probability of exceedance or a return period for a given range of earthquake event. From this

we obtain ground motion from which a given type of structure should be design for.

From the Reference Sites and the Seismo-genetic regions established, we use a radius of

200km of influence area for each site, we integrate the seismic hazard each region provides

for the site and weight them, obtaining as a result total probability for a given event in a site.

Finally we obtain the results of the Seismic Hazard Assessment, represented in a graph of

Probability of exceedance versus PGA, for each site in the study.

y = 1.0066e-103.8x

R = 0.9191y = 0.3107e-54.37x

R = 0.9735y = 0.3107e-61.35x

R = 0.9735y = 0.1115e-57.92x

R = 0.9407y = 1.198e-51.2x

R = 0.8915

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

0 0.1 0.2 0.3

AnnualProbabilityofExce

edance

PGA, g

Results of Seismic Hazard AssessmentTGU

SPS

PC

Roatan

Cholu

Expon. (TGU)

Expon. (SPS)

Expon. (PC)

Expon. (Roatan)

Expon. (Cholu)


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1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

0 0.05 0.1 0.15 0.2

AnnualPro

babilityofExceedance

PGA, g

Results of Seismic Hazard Assessment

TGU

SPS

Puerto Cortes

Roatan

Choluteca


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ELASTIC RESPONSE SPECTRA

With the results obtain in the Seismic Hazard Assessment and according to EuroCode 8, the

return period for which common buildings should be designed for are 95 years for the

Damage Limitation Criteria (DL), and 475 year for the No-Collapse Criteria (NC). This

corresponds to Probability of Exceedance of approximately 1.00E-2 and 2.00E-3, respectively.

Therefore the PGAs for the following sites are:

Site PGA (DL) PGA (NC)

SPS 0.063 g 0.092 g

TGU 0.044 g 0.060 g

PC 0.055 g 0.081 g

Roatan 0.040 g 0.070 gCholuteca 0.092 g 0.125 g

Earthquake Time HistoriesFor the purpose of this study we selected time histories of Earthquakes with similar PGA as

the above, and also with distance from the recording station and the epicenter near the

average distance a probable earthquake may have from one of the reference sites. Following

this guidelines we picked up 6 earthquake time histories, which are summarized in the

following table, 3 of them which are localized to the south of Honduras, affecting mainly the

sites of Choluteca and Tegucigalpa, while the other 3 to the North-West, affecting the sites of

San Pedro Sula, Puerto Cortes and Roatan.

Event Date Station Subsoil Condition Mw PGA

(g)

Distance

(km)

Depth

(km)

EQ1 17/07/03 Guatemala Soft Clay 4.6 0.041 60 40

EQ2 20/01/03 Guatemala Soft Clay 4.4 0.056 25 30

EQ3 13/01/01 El Salvador, Cutuco Rock 7.6 0.079 100 60

EQ4 13/01/01 El Salvador, Acajutla Rock 7.6 0.108 135 60

EQ5 17/02/01 San Salvador Soft Clay 5.1 0.046 30 34

EQ6 14/06/95 Tegucigalpa Stiff Clay 6.6 0.048 50 30


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EQ-1

EQ-2

0 2 4 6 8 10 12 14 16 18 20-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05

Time, [sec]

Acceleration,

[g]

EQ1N-S

EQ1E-W

0 2 4 6 8 10 12 14 16 18 20-0.06

-0.04

-0.02

0

0.02

0.04

0.06

Time, [sec]

Acceleration,

[g]

EQ2N-S

EQ2E-W


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EQ-3

EQ-4

0 5 10 15 20 25 30 35 40 45 50-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

Time, [sec]

Acceleration,

[g]

EQ3N-S

EQ3E-W

0 5 10 15 20 25 30 35 40 45 50-0.15

-0.1

-0.05

0

0.05

0.1

Time, [sec]

Acceleration,

[g]

EQ4N-S

EQ4E-W


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EQ-5

EQ-6

0 5 10 15 20 25 30 35 40-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05

Time, [sec]

Acceleration,

[g]

EQ5N-S

EQ5E-W

0 10 20 30 40 50 60-0.05

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05

Time, [sec]

Acceleration,

[g]

EQ6N-S

EQ6E-W


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Site Specific Response Spectra

With the time histories of the earthquake we can develop response spectra for each

earthquake event, making use of Duhamel integration. We then can normalize this spectrum

with the maximum value, in our case the PGA, and obtain a normalized elastic acceleration

response spectrum. The following are the normalize acceleration response spectra, with 5%

Damping, for the Rock, and soft subsoil conditions

Rock

Stiff Clay

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20.5

1

1.5

2

2.5

3

Period T, [sec]

Sa

EQ3N-S

EQ3E-W

EQ4N-S

EQ4E-W

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20.5

1

1.5

2

2.5

3

3.5

4

Period T, [sec]

Sa

EQ6N-S

EQ6E-W


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Soft Clay

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Period T, [sec]

Sa

EQ1N-S

EQ1E-W

EQ2N-S

EQ2E-W

EQ5N-S

EQ5E-W


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Recommended Elastic Response Spectra

Using the procedure proposed by Newmark-Hall we obtain a smooth response spectrum for

rock subsoil condition, the results are shown below:

Rock

Rock Subsoil Condition Spectral Formulas:

0 TB: SA = (2.7 1) S TTB + 1

TB TC: SA = 2.7 S

TC TD: SA = 2 . 7 S TCT

TD : SA = 2.7 S TCTD T

Using the response spectra for the other ground type conditions we obtain the following soil

amplification factors:

Ground Type Description S

S1 Rock Type with Shear velocity greater than 760m/s 1.00

S2 Hard Dense soil type to medium dense 1.25

S3 Dense soft clay, with less than 6 m of depth 1.35

S4 Soft Clay with more than 12 m of depth, with shear velocity less than 150 m/s 1.65

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

1

1.5

2

2.5

3

Period T, [sec]

Sa

EQ3N-S

EQ3E-W

EQ4N-S

EQ4E-W

Smooth Resp Spec


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The zoning map obtained for Honduras, divided into 6 regions, is shown below:


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For the rock soil condition we show in the following graph both Euro-Code elastic response

spectra for Type 1 and 2 and the recommended spectra in this study.

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

0.5

1

1.5

2

2.5

3

Period T, [sec]

Sa

EQ3N-S

EQ3E-W

EQ4N-S

EQ4E-W

Recomed

EC Type 2

EC Type 1


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COMPARISONS WITH NATIONAL CODE

The Honduran code provides the following ground type classification:

Ground Type Description S Ta Tb e

S1 Rock Type with Shear velocity greater than 760m/s 1.0 0.155 0.364 2.0

S2 Hard Dense soil type to medium dense 1.2 0.186 0.524 2.0

S3 Dense soft clay, with less than 6 m of depth 1.5 0.233 0.818 2.0

S4 Soft Clay with more than 12 m of depth, with shear

velocity less than 150 m/s

2.0 0.310 1.455 2.0

Seismic zoning map of Honduras (factor Z)


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Elastic response Spectra Honduran Code

0 Ta: Sa = 2 . 5 Z g 0.4 + 0.7 TTa

Ta Tb: Sa = 2.75 Z g

Tb : Sa = Z g Se

T

Comparison with Honduran Code

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

0.5

1

1.5

2

2.5

3

Period T, [sec]

Sa

EQ3N-S

EQ3E-W

EQ4N-S

EQ4E-W

Recomend

EC Type 2

EC Type 1

Honduran Code


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REFERENCES

Seismic Hazard Study Hidroelectric Dam Project Site Tornillito

Project Resis II Seismic Hazard Assessment of Central America

- NORSARhttp://www.norsar.no/images/Marketing/Projects/RESIS/Amenaza_Honduras_ES.pdf

Seismic Hazard Assessment of Honduras

- NORSAR & Physics Department UNAHhttp://cidbimena.desastres.hn/ri-hn/pdf/spa/doc14692/doc14692-a.pdf

Euro-Code 8

Honduran National Construction Code

Project Rainbow - Honduras COSMOS -http://db.cosmos-eq.org/

IRIS -http://www.iris.edu/hq/

PMDN (Prevention and Mitigation of Natural Hazards)

SERNA (Secretary of Natural Resources and Environment) -http://www.serna.gob.hn/

National Autonomous University of Honduras (UNAH)

http://www.sirih.org/?nvs=48&title=Gonzalo%20Cruz%20Calder%F3n&lang=es

College of Civil Engineers of Honduras (CICH)

http://cichorg.org/Pages/Biblioteca.aspx
http://www.norsar.no/images/Marketing/Projects/RESIS/Amenaza_Honduras_ES.pdfhttp://www.norsar.no/images/Marketing/Projects/RESIS/Amenaza_Honduras_ES.pdfhttp://cidbimena.desastres.hn/ri-hn/pdf/spa/doc14692/doc14692-a.pdfhttp://cidbimena.desastres.hn/ri-hn/pdf/spa/doc14692/doc14692-a.pdfhttp://db.cosmos-eq.org/http://db.cosmos-eq.org/http://db.cosmos-eq.org/http://www.iris.edu/hq/http://www.iris.edu/hq/http://www.iris.edu/hq/http://www.serna.gob.hn/http://www.serna.gob.hn/http://www.serna.gob.hn/http://www.sirih.org/?nvs=48&title=Gonzalo%20Cruz%20Calder%F3n&lang=eshttp://www.sirih.org/?nvs=48&title=Gonzalo%20Cruz%20Calder%F3n&lang=eshttp://cichorg.org/Pages/Biblioteca.aspxhttp://cichorg.org/Pages/Biblioteca.aspxhttp://cichorg.org/Pages/Biblioteca.aspxhttp://www.sirih.org/?nvs=48&title=Gonzalo%20Cruz%20Calder%F3n&lang=eshttp://www.serna.gob.hn/http://www.iris.edu/hq/http://db.cosmos-eq.org/http://cidbimena.desastres.hn/ri-hn/pdf/spa/doc14692/doc14692-a.pdfhttp://www.norsar.no/images/Marketing/Projects/RESIS/Amenaza_Honduras_ES.pdf

project azure - honduras

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