碩士 / 國立中央大學 / 地球物理研究所 / 100 / Taiwan, located on the boundary between the Eurasia plate (EU) and the Philippine Sea plate (PSP), is an orogenic belt formed by the collision between the Luzon Arc and the continental margin. Most earthquakes occur around Taiwan and along the Ryukyu subduction system with thrusting mechanism. However, there are some events which are associated with strike-slip faulting on the Philippine Sea plate and away from the subduction zone. On 26 April 2010, a strike-slip type of earthquake (Mw = 6.5) occurred on the east of the Gagua Ridge. We deployed 14 OBSs to record its aftershocks in order to acquire more information regarding these strike-slip earthquakes on the oceanic plate. Most aftershocks are clustered and aligned to the NW-SE direction. It indicates that the area is dominated by a sinistral strike-slip mechanism. In West Philippine Basin, two main geological structures, oriented NE-SW and NW-SE, were recognized from bathymetry map. The two features are associated with the spreading event in West Philippine Basin and an old oceanic fracture zone. Since the trending of the cluster in our study is different from the strikes of the two features in the West Philippine Basin, the seismicity seems not to be linked to the reactivation of the former structures. Finally, the aftershock distribution is sparse from 11 to 13 km depth, indicating the presence of Moho discontinuity where the lithospheric strength is weak relatively. This result is consistent with the Moho depth obtaining from the gravity model.
| Identifer | oai:union.ndltd.org:TW/100NCU05134020 |
| Date | January 2012 |
| Creators | Yen-Fu Chen, 陳彥甫 |
| Contributors | Jing-Yi Lin, 林靜怡 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 57 |
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