riesgos volcanicos del eyjafjallajokull y katla

18
Hazard due to eruptions and floods from Katla and Eyjafjallajökull, south Iceland Magnús T. Guðmundsson 1 , Jónas Elíasson 2 , Guðrún Larsen 1 , Ágúst Gunnar Gylfason 3 , Páll Einarsson 1 , Tómas Jóhannesson 4 , Kristín Martha Hákonardóttir 4 and Helgi Torfason 5 1: Institute of Earth Sciences University of Iceland 2: Institute of Engineering, University of Iceland 3: Civil Protection Department, National Commissioner of the Icelandic Police 4: Icelandic Meteorological Office 5: Institute of Natural History This presentation is a summary of project funded by the Government of Iceland. The results are found in a special publication available on the web-page of the Civil Protection Department of the National Commissioner of the Icelandic Police – see end of presentation for details

Upload: vidalbanez

Post on 08-Sep-2014

1.755 views

Category:

Education


2 download

DESCRIPTION

 

TRANSCRIPT

Page 1: Riesgos volcanicos del eyjafjallajokull y katla

Hazard due to eruptions and floods from Katla and Eyjafjallajökull, south Iceland

Magnús T. Guðmundsson1, Jónas Elíasson2, Guðrún Larsen1, Ágúst Gunnar Gylfason3, Páll Einarsson1, Tómas Jóhannesson4, Kristín Martha Hákonardóttir4 and Helgi Torfason5

1: Institute of Earth Sciences University of Iceland 2: Institute of Engineering, University of Iceland3: Civil Protection Department, National Commissioner of the Icelandic Police

4: Icelandic Meteorological Office 5: Institute of Natural HistoryThis presentation is a summary of project funded by the Government of Iceland. The results are found in a

special publication available on the web-page of the Civil Protection Department of the National Commissioner of the Icelandic Police – see end of presentation for details

Page 2: Riesgos volcanicos del eyjafjallajokull y katla

Kortagrunnur utan jökla: Landmælingar ÍslandsBotn Mýrdalsjökuls: Helgi Björnsson o.fl. 12

Botn Eyjafjallajökuls: Sara M. Strachan 13

10 km

Mýrdalsjökull

Eyjafjallajökull

Katla caldera

EyjafjallajökullSummit caldera

Page 3: Riesgos volcanicos del eyjafjallajokull y katla

- Unrest (seismicity, inflation, geothermal activity)- Catastrophic floods to the east well known- New: floods to west more frequent than previously thought

Tasks of hazard assessment for area to the west of the volcanoes:

Eruptions and associated floods caused by ice melting a major hazard

- Estimate eruption frequency for sectors of the volcanoes- Estimate likely flood magnitude- Estimate which areas would be affected by floods

Page 4: Riesgos volcanicos del eyjafjallajokull y katla

Katla caldera – 400-700 m thick iceAbout two eruptions / century

1918 eruption

site

Page 5: Riesgos volcanicos del eyjafjallajokull y katla

Katla - Large phreatomagmatic eruptions

Katla eruption 1918

Page 6: Riesgos volcanicos del eyjafjallajokull y katla

Katla eruptions cause catastrophic jökulhlaups- the 1918 event the largest of its kind in the 20th

century

From Larsen (2000) Kjartan Guðmundsson 1918

Peak discharge 100-300·103 m3s-1

• ~1 km3 of sediments transported• 3 km long peninsula formed at coast

• Katla jökulhlaups one of the largestvolcanological hazards in Iceland

Page 7: Riesgos volcanicos del eyjafjallajokull y katla

Eyjafjallajökull - ice covered stratovolcanoEruptions once every few hundred years

1821-1823eruption

Page 8: Riesgos volcanicos del eyjafjallajokull y katla

Sediments indicaterepeated largejökulhlaups

Drumbabót:Jökulhlaup sediments ~1200 BP

Pathways of 1822 jökulhlaups

Minor flooding 1822

Austur-Landeyjar:sediments from a large jökulhlaup ~1600 BP

Channels of pre-historic jökulhlaups

5 km

Mar

karfl

jót

Álar

Eystri-Rangá

Þverá

Affall

Katla

eruptionsite

Eyjafjallajökull1822

Evidence for hazardous floods towards west

Page 9: Riesgos volcanicos del eyjafjallajokull y katla

ís

dgúlagos í jökli

ís

csprengigos meðgjóskuflóði út ájökul

ís

b

sprungugosí hlíð

ís

a gos undir þykkum jökliTypes of eruptions:

a: Katla 1918, Gjálp 1996

b: Grímsvötn 1998, Eyjafjallajökull ~920

c: Redoubt 1990, Eyjafjallajökull 1821-23?

d: Mount St. Helens 2004 -

a thick ice

b thin ice - flank

c pyroclasticflow

d dome eruption

Page 10: Riesgos volcanicos del eyjafjallajokull y katla

5 km

0 100 200 300 400 500 600 700 800meters

Ice thickness in Eyjafjallajökull and Mýrdalsjökull

Water divides in glaciers

Radio-eccho soundings (Helgi Björnsson er al., 2000; Sara Strachan, 2001)

Eyjafjallajökull Katla

Page 11: Riesgos volcanicos del eyjafjallajokull y katla

5 kmSó

lhei

maj

ökul

l

Jöku

lsár

gilFjal

lgil

Skóg

á

Hrunar Tungna-kvíslajökull

Krossárjökull

Þröngá

Ljósá

Syðri Emstruá

Nyrðri Emstruá

Markarflj

ót

Krossá

Sléttjökull

Entujökull

Kaldak

lifsá

Svaðbælisá

Laugará

Miðskálaá

Holtsá

Írá

AkstaðaáLanganes

Jökulsá SteinholtsáHvanná

Markarfljót

< 100 years100-1.000 years1.000-10.000 years

Recurrence time of eruptions

MNV

ES

EN

MSV

MV

Mýrdalsjökull - northwest partMýrdalsjökull - west flankMýrdalsjökull - southwest flankEyjafjallajökull - north flankEyjafjallajökull - south flank

MNVMVMSVENES

Page 12: Riesgos volcanicos del eyjafjallajokull y katla

5 km

< 3.000 m3 /s3.000-10.000 m3 /s10.000-30.000 m3 /s30.000-100.000 m3 /s> 100.000 m3 /s

1:2:3:4:5:

Magnitude of jökulhlaups caused by eruptionsmaximum discharge:

Sólh

eim

ajök

ull

Jöku

lsár

gilFjal

lgil

Skóg

á

Hrunar Tungna-kvíslajökull

Krossárjökull

Þröngá

Ljósá

Syðri Emstruá

Nyrðri Emstruá

Markarflj

ót

Krossá

Sléttjökull

Entujökull

Kalda

klifsá

Svaðbælisá

Laugará

Miðskálaá

Holtsá

Írá

AkstaðaáLanganes

Jökulsá SteinholtsáHvanná

Markarfljót

Page 13: Riesgos volcanicos del eyjafjallajokull y katla

Catastrophic jökulhlaup (300,000 m3/s)AQUARIVER flood simulation

Timing of flood wave from start of eruption

Page 14: Riesgos volcanicos del eyjafjallajokull y katla

Floods due to eruptionshazard areas - travel times of floods

Water divides

15-30 min from start of eruption Hazard zone boundaries

No eruption-generated

floods

Page 15: Riesgos volcanicos del eyjafjallajokull y katla

Floods from Ljósá and Þröngá – path and travel timesreccurence time of eruptions 1,000-10,000 years

3 hours

Time from source

Water divides

Path of flood

15-30 min

Page 16: Riesgos volcanicos del eyjafjallajokull y katla

Floods Eyjafjallajökull caldera – path and travel timesreccurence time of eruptions 100-1,000 years

Time from source

Water divides

Path of flood

1 - 1.5 hours

15-30 min

Page 17: Riesgos volcanicos del eyjafjallajokull y katla

Results - Hazard assessment

• Recurrence time of eruptions varies between areas - from 50 to 10,000 years

• Recurrence time of large floods to west 500-800 years

• Largest pre-historic floods from Katla caldera ~250,000 m3/s (2 x Amazon River)

• Magnitude of floods due to eruptions on flanks of volcanoes mostly 3,000-10,000 m3/s

• GIS presentation important to convey information to inhabitants and authorities

Page 18: Riesgos volcanicos del eyjafjallajokull y katla

This presentation is a short summary of:

Magnús T. Guðmundsson, Jónas Elíasson, Guðrún Larsen, Ágúst Gunnar Gylfason, Páll Einarsson, Tómas Jóhannesson, Kristín Martha Hákonardóttir og Helgi Torfason. 2005: Yfirlit um hættumat vegna eldgosa og hlaupa frá vesturhluta Mýrdalsjökuls og Eyjafjallajökli. (in Icelandic), (Overview of hazard due to volcanic eruptions and jökulhlaups from the western part of Mýrdalsjökull and Eyjafjallajökull) In: Magnús T. Guðmundsson and Ágúst Gunnar Gylfason (editors): Hættumat vegna eldgosa og hlaupa frá vestanverðum Mýrdalsjökli og Eyjafjallajökli, 11-44. Ríkislögreglustjórinn og Háskólaútgáfan.

In addition to the above overview, the publication on hazard assessment has 11 specialized papers on varous aspects of hazard assessment for the area. All the papers are available on the web-page of the Civil Protection Department of the National Commissioner of the Icelandic police (Ríkislögreglustjóri, Almannavarnadeild):

http://www.almannavarnir.is/orhttp://www.almannavarnir.is/displayer.asp?cat_id=183