South Andaman

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

Little Andaman U.S. DEPARTMENT OF THE INTERIOR EARTHQUAKE SUMMARY MAP U.S. GEOLOGICAL SURVEY Prepared in INDIA cooperation ANDAMAN SEA with the Global Seismographic Car Nicobar M7.8 Northern , , Earthquake of 6 April 2010 Network Tectonic Setting L A O S 80° 90° 100° 110° PLATE Hyderabad Udon Vientiane Vishakhapatnam Thani Phitsanulok Bassein Pegu Savannakhet Rangoon Moulmein Khon Hue EXPLANATION Epicentral Nakhon Kaen Ubon 92° 94° 96° 98° 100° 102° Sawan Ratchathani Da Nang T H A I L A N D Andaman and Trang Quang Main Shock 2004 Songkhla Tavoy Saraburi Nakhon Play Cu Ngai Nicobar Islands Pattani Phra Nakhon Ratchasima Qui Nhon PHILIPPINE SEA Satun Madras Si AyutthaySaamut Batdambang Buon Me V I E T N A M P h i l i p p i n e 1955 Songkhla Pattani F a u l t PLATE Satun Samut Prakan C A M B O D I A Thuot Bangalore B A Y O F Port Mag ≥ 7.0 Northern SumatraY,a Ilandonesia Pondicherry Sakhon Phnom Da Lat Nha Kangar Narathiwat B E N G A L Blair Phan Trang 1941 Penh 0 - 69 km Yala A N D A M A N Vinh Thiet Perlis A0l6o rApril 2010 22:15:02 UTC Kota Long Xuyen Long Bien Hoa Setar Narathiwat Baharu S E A Gulf 70 - 299 10° Madurai Rach Gia 10° of Can Tho My Tho S O U T H 6° 2.36° N., 97.132° E. 6° Thailand Kedah 1881 Nakhon Si Soc 1983 BURMA Thammarat Bac Lieu C H I N A 300 - 600 Banda Depth 31 km Trang N PLATE A Mw = 7.8 (USGS) W H S E A A G S R I L A N K A L U Kuala Songkhla A O P R Plate Boundaries 1936 Pinang Colombo Alor T Terengganu Kandy Yala Kota Kota Pulau2 0P0in kamng (125 miles) WNW of Sibolga, Sumatra, Indonesia Galle EPICENTRAL Banda Setar SUNDA PLATE Kinabalu Kelantan REGION Aceh Baharu Subduction 215 km (135 miles) SW of Medan, Sumatra, Indonesia Pinang Kuala Bandar 515 km (320 miles) W of Kuala, lumpur, Malaysia Terengganu Kuantan B R U N E I Seri 1917 Perak Terengganu Ipoh M Transform 1425 km (880 miles) NW of , , Indonesia A New Port Begawan Medan L A Ipoh Kuala Y S u m a t r a F a u l t S I A Divergent I S Lumpur A Y 1935 A' Kemaman Johor A Seremban L CAROLINE Kuala Baharu Kuching A Aceh Harbor M i d - I n d i a n Melaka M Lipis S I N G A P O R E PLATE B a s i n Singapore Convergent 1916 S u Pekanbaru Pontianak 4° Kuantan 4° 0° m 0° New Port Padang a Active Volcanoes 1936 t Samarinda Pahang r Jambi Balikpapan Medan a 1976 2004 Selangor I N D O N E S I A Kuala Palembang Palangkaraya Bengkulu Bandjermasin Lumpur Kuala Lumpur Negeri PLATE Tanjungkarang- 2002 Shah Telukbetung J A VA S E A Alam Sembilan Seremban

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P l a t e a u N 80° 90° 100° 110° EXPLANATION Riau 1984 RELATIVE PLATE MOTIONS Scale 1:20,000,000 Pini Sumatera Barat Kilometers 1946 0M° ain Shock 0° In the region of this earthquake, the Australia 0 250 500 1,000 1,500 1936 Plate moves northeast with respect to the A 1935 Sunda Plate at about 60-65 mm/yr. Aftershocks Tanahbala 1998 Earthquake Magnitude 2009 4.50 - 5.99 Padang 1943 S u m a t r a 1943 6.00 - 6.99 Siberut

Seismic Hazard 7.00 - 7.99 Jambi 80° 90° 100° 110° Jambi 8.00 - 8.99 Vishakhapatnam Vientiane 1909 KhonUdon 2007 Hyderabad Bassein Phitsanulok 2° 2° Pegu KaenThani Savannakhet Rangoon Moulmein Hue 9.00 - 9.99 Nakhon Ubon Sumatera Nakhon 2008 Sawan Ratchathani Da Nang Sipora Selatan Depth Profile Ratchasima LAOS Bengkulu THAILAND Quang P H IELaIPrtPhI NquE Sake Depth Tavoy Play Cu Ngai 92° 94° 96° 98° 100° 102° Distance (km) Samut Samut A A' Madras Sakhon Prakan Batdambang Qui Nhon 0 - 69 Scale 1:4,235,000 N PNagotaei on earthquakes: From 1900-1963, earthquakes shown are from Bangalore Phnom VIETNAM Centennial Catalog, magnitudes greater than 5.5. From 1964-2002, -300 -200 -100 0 100 200 300 Pondicherry Port Buon Me Nha Trang Kilometers Blair CAMBODIA Penh ThuotDa Lat 70 - 299 earthquakes are from HDF catalog, magnitudes greater than 4.5. From Ho Chi Minh City 0 125 250 500 2003 to present, earthquakes are from NEIC, magnitudes greater than 4.5. Vinh 300 - 700 S Pagai Rach Gia Long Phan 10° Madurai Long Xuyen 10° Can Tho My ThoThiet Nakhon Si Bac Lieu Soc Thammarat Trang 0 0 MALAYSIA Colombo Songkhla Significant Earthquakes Mag ≥ 7.0 I N D O N E S I A Kandy Alor Kota Banda Setar Yala Kuala Galle Kinabalu Aceh Pinang Terengganu Bandar Seri Year Mon Day Time Lat Long Dep Mag Ipoh Begawan 1907 01 04 0519 2.000 94.500 50 7.5 -100 -100 Kuala Kuantan 1909 06 03 1840 -2.000 101.000 0 7.2 Medan ) Lumpur New Port 1916 07 27 1152 4.000 96.500 100 7.0 m k

Seremban (

1917 11 04 1203 4.800 96.800 0 7.1 Melaka Johor h

Kuching t Baharu Singapore 1935 08 03 0110 4.430 96.326 35 7.0 TECTONIC SUMMARY p

Pekanbaru 1935 12 28 0235 -0.345 98.147 35 7.8 e -200 -200 Pontianak 1936 01 02 2234 -0.279 98.872 35 E7n.g0gano D 0° Samarinda 0° The , Sumatra earthquake of April 6, 2010 occurred as a result of thrust Padang Balikpapan 1936 08 23 2112 5.296 94.759 35 7.1 Jambi faulting on or near the subduction interface plate boundary between the Australia-India 1936 09 19 0101 3.648 97.551 35 7.1 EPICENTRAL REGION Palangkaraya and Sunda plates. At the location of this earthquake, the Australia and India Plates move 1943 06 08 2042 -1.000 101.000 50 7.2 Palembang Bandjermasin north-northeast with respect to the Sunda plate at a velocity of approximately 60-65 1943 06 09 0306 -1.000 101.000 50 7.5 Bengkulu mm/yr. On the basis of the currently available fault mechanism information and 1946 05 08 0520 0.000 99.500 0 7.1 -300 J a v a -300 Tanjungkarang- 1955 05 17 1449 6.738 93.754 29.1 7.2 earthquake depth, it is likely that this earthquake occurred along the plate interface. -300 -200 -100 0 100 200 300 Telukbetung IN D O NE S I A 1969 11 21 0205 1.973 94.574 11 7.6 Jakarta The subduction zone surrounding the immediate region of this event last slipped during the 1971 02 04 1533 0.552 98.665 60 7.1 Bandung Semarang 1976 06 20 2053 3.437 96.254 16.2 7.0 Yogyakarta Surabaya Mw 8.6 earthquake of March 2005, and today's event appears to have occurred within the 1983 04 04 0251 5.724 94.694 94.5 7.0 Mataram rupture zone of that earthquake. Today's earthquake is the latest in a sequence of large 1984 11 17 0649 0.179 97.959 28.7 7.1 ruptures along the , including two M 7.4 earthquakes beneath Simeulue 1998 04 01 1756 -0.544 99.217 32 7.0 0 0 10° 10° 125 km to the north in 2002 and 2008; a M 9.1 earthquake that ruptured to within 125 km 2002 11 02 0126 2.824 96.085 30 7.4 2004 12 26 0058 3.295 95.982 30 9.0 north of this earthquake in 2004; a M 8.5 375 km to the south in 2007; and a M 7.5 260 km DATA SOURCES to the south near Padang in 2009. 2004 12 26 0421 6.910 92.958 39 7.2 REFERENCES 2005 03 28 1609 2.085 97.108 30 8.6 EARTHQUAKES AND SEISMIC HAZARD Bird, P., 2003, An updated digital model of plate boundaries: 2007 09 13 0335 -2.130 99.627 22 7.0 USGS, National Earthquake Information Center Geochem. Geophys. Geosyst., v. 4, no. 3, pp. 1027- 80. 2008 02 20 0808 2.768 95.964 26 7.4 NOAA, National Geophysical Data Center 80° 90° 100° 110° IASPEI, Centennial Catalog (1900 - 1999) and 2008 02 25 0836 -2.486 99.972 25 7.2 Engdahl, E.R. and Villaseñor, A., 2002, Global Seismicity: extensions (Engdahl and Villaseñor, 2002) 1:20,000,000 1900 - 1999, chap. 41 of Lee, W.H.K., and others,eds., Seismic hazard is expressed as peak Scale 2009 09 30 1016 -0.720 99.867 81 7.5 HDF (unpublished earthquake catalog) (Engdahl, 2003) International Earthquake and Engineering Seismology, Kilometers 2010 04 06 2215 2.360 97.132 31 7.8 Global Seismic Hazard Assessment Program ground acceleration (PGA) on firm Part A: New York, N.Y., Elsevier Academeic Press, 932 p. rock, in meters/sec², expected to be 0 250 500 1,000 1,500 AND FAULT MODEL exceeded in a 50-yr period with a DISCLAIMER Engdahl, E.R., Van der Hilst, R.D., and Buland, R.P., 1998, PB2002 (Bird, 2003) probability of 10 percent. Global teleseismic earthquake relocation with improved trav- Finite Fault Model, Chen Ji, UC Santa Barbara (2007) Base map data, such as place names and political el times and procedures for depth determination: Bull. Seism. Peak Ground Acceleration in m/sec**2 Soc. Amer., v. 88, p. 722-743. boundaries, are the best available but may not be BASE MAP current or may contain inaccuracies and therefore NIMA and ESRI, Digital Chart of the World Map prepared by U.S. Geological Survey should not be regarded as having official significance. USGS, EROS Data Center National Earthquake Information Center NOAA GEBCO and GLOBE Elevation Models 20 April 2010 .2 .4 .8 1.6 2.4 3.2 4.0 4.8 ESRI Online Map not approved for release by Director USGS