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MCEER Bulletin, Volume 24, Number 1, Spring 2010

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Volume 24, Number 1, Spring 2010

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Report on the West Sumatra Earthquake of September 30, 2009

A government office building in Padang suffered damage due to soft story collapse mechanism.

A government office building in Padang suffered damage due to soft story collapse mechanism.

A team of engineers from the Institute of Technology, Bandung, Indonesia, investigated the devastating effects of the West Sumatra earthquake of September 30, 2009, with support from MCEER. The team, comprised of Dyah Kusumastuti, Made Suarjana, I. Wayan Sengara and Rildova, visited the impacted area about a month after the earthquake. Dr. Kusumastuti received her Ph.D. from the University at Buffalo and Dr. Rildova received his Ph.D. from Virginia Polytechnic Institute and State University. Both participated in MCEER research while completing their degrees.

Bridge damage due to ground settlement within the fill of the approach and displacements of abutment side walls.

Bridge damage due to ground settlement within the fill of the approach and displacements of abutment side walls.

The West Sumatra earthquake occurred at 17:16:09 local time (10:16:09 GMT) on September 30, 2009 with a moment magnitude of (Mw) 7.6, epicenter of 0.789°S, 99.961°E, and depth of 80 km (USGS and BMKG - Indonesian Meteorology, Climatology, and Geophysical Agency). The earthquake was located in the subduction zone of the Indo-Australian and Eurasia plate. The reported peak ground acceleration (PGA) at the Andalas University, Padang, was approximately 0.3g.

The earthquake caused more than 1,100 fatalities and 3,000 injuries, damaging more than 100,000 structures, with losses estimated at IDR 21.6 trillion (USD 2.3 billion), as quoted from an official report by the Indonesian National Disaster Management Agency. Most of the losses were caused by damage to infrastructure, especially housing. The team focused their efforts on the city of Padang, with a particular interest in school buildings and public facilities.

A brief summary of the reconnaissance mission is available from the MCEER website. A full length MCEER technical report is in preparation.

–Submitted by Dyah Kusumastuti,
Institute of Technology, Bandung, Indonesia