EERC TEAMAn Overview

Ragnar Sigbjörnsson

UPStrat-MAFA Workshop, Selfoss 24-27 July 2012

Prelude• South Iceland Lowland has been our ‘field laboratory’ for

the last 25 years• Research aimed towards seismic risk reduction• Close cooperation with the local people• The Rector of the University of Iceland and the Mayor of

Árborg signed a contract in 1997 that lead to the establishment of EERC

• The Centre was officially opened in 2000

The EERC TeamAcademic staff: Dr. Ragnar Sigbjörnsson, Professor, Director Dr. Símon Ólafsson, Research Professor Dr. Jónas Elíasson, Research Professor Dr. Benedikt Halldórsson, Assoc. Research Professor Dr. Rajesh Rupakhety, Assoc. Research Professor Sólveig Thorvaldsdóttir, MSE, Research Engineer Ásthildur Elva Bernhardsdóttir, cand oecon, MA, Rsrch Scientist Sigurdur Unnar Sigurdsson, MSc, Research Engineer Aldís Sigfúsdóttir, MSc, PE, Research Engineer

Visiting Professors: Dr. Athol J. Carr, Professor Dr. John Douglas, Research Scientist Dr. Apostolos S. Papageorgiou, Professor Dr. Jónas Thór Snæbjörnsson, Professor

Office staff: Elínborg Gunnarsdóttir, Manager Katrín Kristjánsdóttir, Research Assistant

Doctoral students:• Ævar Harðarson, MArch • Fjóla G. Sigtryggsdóttir, MSc• Ole André Oiseth, MSc

MSc-students: Teaching and Research Assistants:• Jón Einarsson Anna Beta Gísladóttir• Puja Rupakhety Einar Óskarsson• Hrafnkell Már Stefánsson Hörður Páll Steinarsson

Steinar Þór Backmann

The EERC Team

International Cooperation

-180 -120

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0

60

120

180

-90

-60

-30

0

30

60

90

The EERC TeamParticipating in the Workshop

Dr. Ragnar Sigbjörnsson, Professor, Director Dr. Símon Ólafsson, Research Professor Dr. Rajesh Rupakhety, Assoc. Research Professor Sólveig Thorvaldsdóttir, MSE, Research Engineer Ásthildur Elva Bernhardsdóttir, MA, Research Scientist

Guests - Visiting Professors: Dr. Jónas Thór Snæbjörnsson, Professor Dr. Radan Ivanov, Professor

Office staff: Elínborg Gunnarsdóttir, Manager Katrín Kristjánsdóttir, Research Assistant

Seismicity of Iceland An Introduction

Ragnar Sigbjörnsson

UPStrat-MAFA Workshop, Selfoss 24-27 July 2012

Contents

• Seismo-tectonics of Iceland• Earthquake catalogue data• Macroseismic field data• Strong-motion data• Seismic hazard maps

Seismo-tectonics of Iceland

References:

Sigbjörnsson, R & Ólafsson, S. (2004). On the South Iceland earthquakes in June 2000: strong-motion effects and damage. Bollettino di Geofisica Teorica e Applicata, 45(3): 131-152

ICELAND

MID-ATLANTIC RIDGE

MID-ATLANTIC RIDGE

SISZ

TFZ

~ 1 cm/yr

~ 1 cm/yr

Active central volcanoes (yellow), calderas (red) and fissure swarms (green)

Volcanic zones and earthquakeso earthquake > 4 after 1896; & recorded by IceSMN; earthquakes 2000 og 2008

Results of GPS-measurements

O recording station; lines indicate velocity and direction

Active plate boundary

North-American Plate

Eurasian Plate

Volcanic zones and earthquakeso earthquake > 4 after 1896; & recorded by IceSMN; earthquakes 2000 og 2008

Vulcanic zones, earthquakes and active plate boundary

Earthquake in South Iceland Seismic Zone the last 100 years

Surface fracture 21 June 2000

Landslide 21 June 2000

Damage to road 21 June 2000

Damage to farm building21 June 2000

Damage to residential house17 June 2000

Inside a residential house 17 June 2000

PTSD June 2000

The Árborg Town Hall: The strong-motion array

Ground accelerationBasement of Town Hall at Selfoss, 29 May 2009

Response acceleration3rd floor of the Town Hall at Selfoss, 29 May 2009

Inside the EERC building University of Iceland

29 May 2008

The Árborg Town Hall: Displacement (cm) during the 29. maí 2008 earthquake

Earthquake Catalogue of Iceland

References:

Ambraseys, N.N. & Sigbjörnsson, R (1999). Re‑Appraisal of the Seismicity of Iceland, Polytechnica - Engineering Seismology, Reykjavik, ISSN 0255-9226

Ambraseys, N.N. & Sigbjörnsson (2003). On the seismicity of northwestern Europe: A comparative study of earthquake catalogues, Department of Civil and Environmental Engineering, Imperial College of Science, Technology and Medicine, London, UK, Research report number: 03-001-SM, www.imperial.ac.uk/

References in the above mentioned publications

Parametric Catalogue for Iceland (Ambraseys and Sigbjörnsson, 2000)

Quantity Value

magnitude scale

geographic area

period

total number of events

events with recalculated magnitude

range of recalculated magnitudes

Surface-wave magnitude, MS

62°N to 68°N and 26°W and 12°W

1896 to 1996

422

276

3.0 – 7.2

Temporal distribution of events in the Parametric Earthquake Catalogue for Iceland

1900 1920 1940 1960 1980 20000

5

10

15

20

25

30

TIME (years)

DE

NS

ITY

(nu

mb

er/

yea

r)

Reykjavík

Vatnajökull

26 W

20 W 18

W 16

W

14 W

12 W

62 N

63 N

64 N

65 N

66 N

67 N

68 N

24 W

22 W

Spatial distribution of earthquake epicentres in the Parametric Earthquake Catalogue for Iceland

Time-line of the Parametric Earthquake Catalogue for Iceland showing surface-wave magnitude as a function of time

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 20003

3.5

4

4.5

5

5.5

6

6.5

7

7.5

8

TIME (year)

MA

GN

ITU

DE

Distribution of surface-wave magnitudes from the Parametric Earthquake Catalogue for Iceland

2 3 4 5 6 7 80

10

20

30

40

50

60

70

80

90

100

MAGNITUDE

NU

MB

ER

OF

EV

EN

TS

3 4 5 6 7 810

-3

10-2

10-1

100

MAGNITUDE

CU

MU

LA

TIV

E F

RE

QU

EN

CY

(a) histogram (b) cumulative distribution .

Macroseismic Field Data

References:

Ambraseys, N.N. & Sigbjörnsson, R (1999). Re‑Appraisal of the Seismicity of Iceland, Polytechnica - Engineering Seismology, Reykjavik, ISSN 0255-9226

Strong-motion Data

References:

Ambraseys, N.N. et al. (2002). ISESD – Internet Site for European Strong-Motion Data. European Com mission, Research-Directorate General, Environment and Climate Programme.

Ambraseys, N.N. et al. (2004). Internet Site for European Strong-Motion Data. Bollettino di Geofisica Teorica e Applicata, 45(3): 113-129

http://www.ISESD.hi.is

The Icelandic Strong-motion Network, IceSMN ● ground station; ▲ power plant; ▲ dam; ▼ bridge; ■ building

Strong-motion Data• The records are available on the Internet• ISESD – European Databank

Information ...

http://www.isesd.hi.is/

Earthquake Hazard Mapsfor structural design purposes

References:

http://eerc.hi.is, the hazard maps were derived by Ragnar Sigbjörnsson in 2002

24 W

22 W 20

W 18

W 16

W

14 W

63 N

64 N

65 N

66 N

67 N

Peak ground acceleration with 10% probability of exceedance in 50 years

> 40% g20-40% g10-20% g5-10% g2-5% g< 2% g

24 W

20 W 18

W 16

W

14 W

63 N

64 N

65 N

66 N

67 N

22 W

Magnitude of the dominating event contributing to PGA with 10% probability of exceedance in 50 years

> 6.56.0-6.55.5-6.0< 5.5

67 N

22 W 20

W 18

W 16

W

14 W

63 N

64 N

65 N

66 N

24 W

Source distance of the dominating event contributing to PGA with 10% probability of exceedance in 50 years

< 10 km10-20 km20-50 km50-100 km> 100 km

Significant Duration – June 2000

1 2 5 10 20 50 1000

5

10

15

20

25

30

35

40

DISTANCE (km)

DU

RA

TIO

N (

s)

The seismic source zones and lineaments applied in probabilistic seismic hazard analysis

Source zone

A

B1

C

B2

D

E

F

G

J

B3

UPStrat-MAFA Workshop, Selfoss 24-27 July 2012