September 30, 2009 Earthquake: Padang, Sumatra, Indonesia

Felt Report

At least 1,117 people killed, 1,214 injured, 181,665 buildings destroyed or damaged and about 451,000 people displaced in the Padang-Pariaman area. Landslides disrupted power and communications in the area. Felt (VII) at Padang; (VI) at Bukittinggi; (IV) at Bengkulu, Duri, Mukomuko and Sibolga; (III) at Pekanbaru. Also felt (IV) at Gunungsitoli, Nias and (II) at Jakarta, Java. Felt throughout Sumatra and in much of Java. Felt (III) in Singapore and at George Town, Johor Bahru, Kuala Lumpur, Petaling Jaya, Shah Alam and Sungai Chua, Malaysia. Felt in much of Peninsular Malaysia and as far away as Chiang Mai, Thailand. A local tsunami was recorded at Padang, Sumatra.

Tectonic Summary

The magnitude 7.6 southern Sumatra earthquake of September 30, 2009 occurred as a result of oblique-thrust faulting near the subduction interface plate boundary between the Australian and Sunda plates. At the location of this earthquake, the Australian Plate moves northeast with respect to the Sunda plate at a velocity of approximately 65 mm/yr.

On the basis of the currently available fault mechanism information and earthquake depth of 80 km, it is likely that this earthquake occurred within the subducting Australian Plate rather than on the plate interface itself. The recent earthquake was deeper than typical subduction thrust earthquakes that generally occur at depths less than 50 km.

The subduction zone surrounding the immediate region of this event has not witnessed a megathrust earthquake in the recent past, rupturing last in an earthquake of M 8.5 or larger in 1833. Approximately 350 km to the south, a 250 km section of the plate boundary slipped during an Mw 8.4 earthquake in September 2007, while approximately 300 km to the north, a 350 km section slipped during the Mw 8.7 earthquake of March 2005. In early 2008, the plate boundary updip of today's earthquake was active in a sequence of Mw 5-6 earthquakes. It is not clear how today's earthquake is related to the sequence of megathrust subduction zone events on the shallower section of the plate boundary.

(above from reference #1053)

CNN Report

A major earthquake in Indonesia killed at least 75 people Wednesday, according to a Red Cross disaster report, citing an official report from the country's vice president. Earlier in the day an official said the quake toll was at least 21, with hundreds more injured. Thousands may be trapped by collapsed buildings and houses, said Rustam Pakaya, the head of Ministry of Health's crisis center. He said 75 people were seriously injured. The quake caused widespread power and phone outages, making it difficult to assess the scope of the damage. It struck at around 5 p.m. local time, about 33 miles (53 kilometers) from Padang, the capital city of West Sumatra. Padang is home to more than 800,000 people. State-run Antara news agency cited Pakaya as saying he had received reports that part of a hospital had collapsed and that people were buried under the debris. Hundreds of houses have been damaged, Wayne Ulrich, the Red Cross disaster management coordinator in Indonesia, told CNN. (reference #5358)

2009, Sept 30, Indonesia, Padang, Kota Padang, Buki, 1195 killed, 2,501,798 affected, $2200 damage. (reference #1250)

1,195 fatalities, 2.077 billion USD economic loss (reference #13727)