Poster Gempa Tektonik Sumatera 11 April 2012 dari USCGS

EARTHQUAKE SUMMARY MAPU.S. DEPARTMENT OF THE INTERIORU.S. GEOLOGICAL SURVEY

ANDAMAN SEA

A n d a m a n B a s i n

Middle Andaman

South Andaman

Little Andaman

INDIACar Nicobar

S u m a t r aSiberut

Sipora

N Pagai

S Pagai

Enggano

Pini

Nias

Tanahbala

1907

1935

1943

1969

2004

2005

2007

2009

2010

2010

2010

Ranong

SuratThani

Phangnga

KrabiPhuket

PhatthalungTrang

Pattani

SatunKangar

Nakhon SiThammarat

Songkhla

Yala

AlorSetar

BandaAceh

Ipoh

Padang

Pinang

Medan

2004

2005

A

A'

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92°

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SUN DA (J AVA) TRENC H

AUSTRALIA PLATE

BURMAPLATE

SUNDA PLATE

AUSTRALIAPLATE

S O U T HC H I N A

S E A

J A V A S E A

A N D A M A NS E A

B A Y O FB E N G A L

Sumatra

Java

Greater Sunda Is lands

S u m a t r a F a u l t

I N D O N E S I A

S R I L A N K A

T H A I L A N D

S I N G A P O R E

MA

LA

YS

I A

C A M B O D I AV I E T N A M

Gulfof

Thailand

M i d - I n d i a nB a s i n

Ni

ne

ty

E

as

t

Ri

dg

e

Inv

es

tiga

t or R

i dg

e

O s b o r nP l a t e a u

1941

EURASIA PLATE

2005

1861

2004

1833

1881

2004

2005

2007

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M8.6 Northern Sumatra, Earthquake of 11 April 2012

0 200 400100Km

VIETNAM

CAMBODIA

LAOSTHAILAND

MALAYSIA

KuantanNew Port

PhitsanulokBassein SavannakhetMoulmein HueKhonKaen Da NangNakhon

Sawan UbonRatchathani

QuangNgaiNakhon

Ratchasima

Tavoy Play CuQui NhonSamut Prakan

SamutSakhon

SiemreabBatdambang Buon Me

Thuot

NhaTrang

Da LatPortBlair

Bien HoaPhanThiet

Tan AnMy Tho

Vinh Long

Can ThoRach Gia

SocTrang

Bac LieuNakhon SiThammarat

SongkhlaYala Kota

BaharuAlorSetarBanda

Aceh KualaTerengganu

Ipoh

SerembanMelaka

JohorBaharu

PekanbaruPontianak

Padang

Jambi

Bengkulu

Tanjungkarang-Telukbetung

Pinang

Rangoon

PhnomPenh Ho Chi

Minh City

Medan KualaLumpur

Palembang

Bandung

Singapore

Bangkok

Jakarta

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100°

90°

90°

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Km

Scale

Prepared in cooperation

with the Global Seismographic

Network

Tectonic Setting

Seismic Hazard

Epicentral Region

TECTONIC SETTING

The M8.6 April 11, 2012 earthquake off the west coast of northern Sumatra, Indonesia, occurred asa result of strike-slip faulting within the oceanic lithosphere of the Indo-Australia plate. The quakewas located approximately 100 km to the southwest of the major subduction zone that defines theplate boundary between the Indo-Australia and Sunda plates offshore Sumatra. At this location, theIndo-Australia plate moves north-northeast with respect to the Sunda plate at a velocity ofapproximately 52 mm/yr.

Large strike-slip earthquakes, while rare, are not unprecedented in this region of the Indo-Australianplate. Since the massive M 9.1 earthquake that ruptured a 1300 km long segment of the Sumatranmegathrust plate boundary in December of 2004, three large strike-slip events have occurred within50 km of the April 11, 2012 even. These earthquakes occurred on April 19 2006 (Mw6.2), October4 2007 (Mw6.2) and January 10, 2012 (Mw7.2). In all three cases, the style of faulting was similar.These events align approximately with fabric of the sea floor in the diffuse boundary zone betweenthe Indian and Australian plates.

EXPLANATION

Great RuptureYear

Rupture Zone

Mag ≥ 7.00 - 69 km70 - 299300 - 600Active VolcanoesRELATIVE PLATE MOTIONS

In the region of this earthquake,earthquakes define the boundarybetween the South American andNazca Plates, which are convergingat about 80 mm/yr.

0 500 1,000

Km

Scale

1:4,840,000Scale

Significant Earthquakes Mag >= 7.5

Year Mon Day Time Lat Long Dep Mag1907 01 04 0519 2.000 94.500 50 7.51935 12 28 0235 -0.345 98.147 35 7.81943 06 09 0306 -1.000 101.000 50 7.51969 11 21 0205 1.973 94.574 11 7.62004 12 26 0058 3.295 95.982 30 9.02005 03 28 1609 2.085 97.108 30 8.62007 09 12 2349 -2.625 100.841 35 7.92009 09 30 1016 -0.720 99.867 81 7.52010 04 06 2215 2.383 97.048 31 7.82010 06 12 1926 7.881 91.936 35 7.52010 10 25 1442 -3.487 100.082 20 7.82012 04 11 1043 0.773 92.452 16 8.22012 04 11 1043 0.773 92.452 16.4 8.2

EPICENTRAL REGION

1:15,000,000

1:15,000,000

EPICENTRALREGION

Depth ProfileA A'

Dep

th (k

m)

Distance (km)

Earthquakes locations are from the CentennialCatalog (1900-2003) and from NEIC (2003-present)

Northern Sumatra Earthquake 11 April 2012 8:38:37 UTC 2.348° N., 93.072° E.Depth 25 kmMw = 8.6 (USGS)

EXPLANATION

Earthquakes 1900 - 2011M 4.50 - 5.99M 6.00 - 6.99

M 7.00 - 7.99

M >= 8.00

Aftershocks

Earthquake Depth0 - 6970 - 299300 - 700

Rupture ZoneActive Volcanoes

Peak GroundAcceleration m/sec**2

.2

.4

.8

1.6

2.4

3.24.0

4.8

9.8

PAGER

DATA SOURCES

EARTHQUAKES AND SEISMIC HAZARD USGS, National Earthquake Information Center NOAA, National Geophysical Data Center IASPEI, Centennial Catalog (1900 - 1999) and extensions (Engdahl and Villaseñor, 2002) HDF (unpublished earthquake catalog) (Engdahl, 2003) Global Seismic Hazard Assessment Program

PLATE TECTONICS AND FAULT MODEL PB2002 (Bird, 2003) Finite Fault Model, Chen Ji, UC Santa Barbara (2007) World Slap (Hayes and Wald, 2010)

BASE MAP NIMA and ESRI, Digital Chart of the World USGS, EROS Data Center NOAA GEBCO and GLOBE Elevation Models

REFERENCES

Bird, P., 2003, An updated digital model of plate boundaries: Geochem. Geophys. Geosyst., v. 4, no. 3, pp. 1027- 80.

Engdahl, E.R. and Villaseñor, A., 2002, Global Seismicity: 1900 - 1999, chap. 41 of Lee, W.H.K., and others,eds., International Earthquake and Engineering Seismology, Part A: New York, N.Y., Elsevier Academeic Press, 932 p.

Engdahl, E.R., Van der Hilst, R.D., and Buland, R.P., 1998, Global teleseismic earthquake relocation with improved trav- el times and procedures for depth determination: Bull. Seism. Soc. Amer., v. 88, p. 722-743.

The GEBCO_08 Grid, version 20090202, http://www.gebco.net

Hayes, Gavin, and Wald, David, 2010, Slab models for subduction zones: USGS, http://earthquakes.usgs.gov/research/data/slab

DISCLAIMER

Base map data, such as place names and politicalboundaries, are the best available but may not be current or may contain inaccuracies and thereforeshould not be regarded as having official significance.

Map prepared by U.S. Geological SurveyNational Earthquake Information Center11 April 2012Map not approved for release by Director USGS

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Depth Profile Area

Northern Sumatra Earthquake 11 April 2012 10:43:09 UTC 0.773° N., 92.4522° E.Depth 16 kmMw = 8.2 (USGS)

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