Aftershock Observation of the 27 May 2006 Yogyakarta earthquake and Subsurface Structure Determination
Abstract
The moment magnitude 6.2 May 27, 2006, Yogyakarta earthquake resulted in extensive damage in Yogyakarta Special Province and the southern part of Central Java Province, Java, Indonesia. Over 6,000 persons died and over 20,000 persons were injured. The geological setting is dominated by a series of faults in and near a graben containing the City of Yogyakarta (population 517,000). The graben is filled with a variety of volcanic derived sediments from lahars and ash falls from Mt. Merapi, an active stratovolcano located approximately 30 kilometers north of Yogyakarta. The structure and sediments within the Yogyakarta basin heavily influence seismic wave propagation in the basin. Precise aftershock distribution is important to understand the mechanism of earthquake generation. To study the aftershock activity, Kyushu University collaborated with Gadjah Mada University deployed four seismometers at four sites in the source region. We started our observations nine days after the main shock for an observation period of approximately three months. From the overall data, two hundred aftershocks were located with high spatial resolution. We found that most of the aftershocks occurred on the fault plane of the strike-slip mainshock. The objective of the observations was to delineate the distribution of the aftershock epicenters and used it to clarify the subsurface structure. Hopefully understanding the structural and seismogenic setting of the Yogyakarta basin will help to minimize the impacts of similar hazard around Yogyakarta region in the future and assist in the development of the region's first microzonation map for seismic hazards with respect to strong ground shaking.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFM.S23E0209M
- Keywords:
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- 7200 SEISMOLOGY;
- 7212 Earthquake ground motions and engineering seismology;
- 7299 General or miscellaneous