Magnitude 7.2 quake followed by dozens of strong aftershocks rattle the Indonesian island of Kepulauan Talaud
Earthquake Details
Magnitude: 7.2
Date-Time: Thursday, February 12, 2009 at 01:34:50 AM at epicenter
Location: 3.902°N, 126.400°E
Depth: 20 km (12.4 miles) set by location program
Region: KEPULAUAN TALAUD, INDONESIA
Distances:
- 280 km (175 miles) SSE of General Santos, Mindanao, Philippines
- 320 km (195 miles) NNE of Manado, Sulawesi, Indonesia
- 1320 km (820 miles) SSE of MANILA, Philippines
- 2445 km (1520 miles) ENE of JAKARTA, Java, Indonesia
Location Uncertainty: horizontal +/- 6.3 km (3.9 miles); depth fixed by location program
Source: USGS NEIC (WDCS-D)
USGS Event ID: us2009cybb
Tectonic Summary [USGS]
The recent earthquake near Kepulauan Talaud, Indonesia of February 11, 2009 likely occurred as a result of reverse faulting on or near the plate-boundary system separating the Philippine Sea and Celebes Sea basins. Northeastern Indonesia is characterized by complex tectonics in which motions of numerous small plates are accommodating large-scale convergence between the Philippine Sea and Sunda plates. In the region of today’s earthquake, the Philippine Sea plate moves west-northwest with respect to the Sunda plate at a velocity of about 62 mm/year. Locally, arc-arc collision is occurring between the Sangihe and Halmahera micro plates, wedging between them the Molucca Sea micro plate, which subducts beneath both (i.e. to the east and west) and forms an inverted-U-shaped seismic zone. Seismicity within the Molucca Sea plate is active to depths of approximately 260 km to the east and 400 km to the west. The tectonic setting of this region is unique in that it is the only global example of an active arc-arc collision consuming an oceanic basin via subduction in two directions.
“The earthquake occurred approximately 30 km off the western coast of the Pulau Salebabu (Indonesia) in an area that has seen large earthquakes in the past. Since 1986, there have been two earthquakes with magnitude greater than 7 in this region.
Indonesia
Indonesia consists of more than 17,500 islands scattered over both sides of the equator, about 6,000 of which are inhabited.The five largest islands are Java, Sumatra, Kalimantan (the Indonesian side of Borneo), New Guinea (shared with Papua New Guinea) and Sulawesi.
Indonesian islands sit on the edges of the Australian, Eurasian and Pacific tectonic plates and are therefore subject to frequent earthquakes and volcanic eruptions. Indonesia is home to about 160 active volcanoes.
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