EARTHQUAKE IN SOUTHWEST OF BENGKULU – SUMATRA, INDONESIA
The following is a release by the United States Geological Survey, National Earthquake Information Center: An earthquake occurred 130 km (80 miles) SW of Bengkulu, Sumatra, Indonesia and 625 km (390 miles) WNW of JAKARTA, Java, Indonesia at 5:10 AM MDT, Sep 12, 2007 (6:10 PM local time in Indonesia). The magnitude and location may be revised when additional data and further analysis results are available. Earthquakes of this type sometimes cause tsunamis, however the USGS has no information that an actual tsunami has been generated. For information about tsunamis, contact the NOAA Tsunami Warning Centers at http://tsunami.gov.
At least 9 people killed, hundreds injured and many buildings damaged or destroyed in the Bengkulu and Padang areas. A tsunami with a wave height of 90 cm was measured at Padang. Power and telephone outages occurred. Felt by people in high-rise buildings at Jakarta and in Malaysia, Singapore and Thailand.
The southern Sumatra earthquake of September 12, 2007 occurred as the result of thrust faulting on the boundary between the Australian plate and the Sunda plate. At the location of the earthquake, the Australia plate moves northeast with respect to the Sunda plate at a velocity of about 69 mm/year. The direction of relative plate motion is oblique to the orientation of the plate boundary offshore of the west coast of Sumatra. The component of plate-motion perpendicular to the boundary is accommodated by thrust faulting on the offshore plate-boundary. Much of the component of plate motion parallel to the plate boundary is accommodated by strike-skip faulting on the Sumatra fault, which is inland on Sumatra proper.
The earthquake of September 12, 2007 is the fourth earthquake of magnitude greater than 7.8 to have occurred in the past decade on or near the plate boundaries offshore of western Sumatra. The September 12, 2007 earthquake occurred just north of the source region of the magnitude 7.8 earthquake on June 4, 2000, which killed approximately 100 people. The great magnitude 9.1 earthquake of December 26, 2004, which produced the devastating Indian Ocean tsunami of that date, ruptured much of the boundary separating the India plate and the Burma plate. Immediately to the south of the great 2004 earthquake, the magnitude 8.6 Nias Island earthquake of March 28, 2005, ruptured a segment of the plate boundary separating the Australia and Sunda plates.
- USGS website – http://earthquake.usgs.gov/