Interseismic deformation and moment deficit along the Manila subduction zone and the Philippine Fault system

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• 作者：Ya‐Ju Hsu ; Shui‐Beih Yu ; John P. Loveless ; Teresito Bacolcol ; Renato Solidum ; Artemio Luis Jr ; Alfie Pelicano ; Jochen Woessner
• 刊名：Journal of Geophysical Research: Solid Earth
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：121
• 期：10
• 页码：7639-7665
• 全文大小：9.5MB
• ISSN：2169-9356

文摘

We examine interseismic coupling of the Manila subduction zone and fault activity in the Luzon area using a block model constrained by GPS data collected from 1998 to 2015. Estimated long-term slip rates along the Manila subduction zone show a gradual southward decrease from 90–100 mm/yr at the northwest tip of Luzon to 65–80 mm/yr at the southern portion of the Manila Trench. We provide two block models (models A and B) to illustrate possible realizations of coupling along the Manila Trench, which may be used to infer future earthquake rupture scenarios. Model A shows a low coupling ratio of 0.34 offshore western Luzon and continuous creeping on the plate interface at latitudes 18–19°N. Model B includes the North Luzon Trough Fault and shows prevalent coupling on the plate interface with a coupling ratio of 0.48. Both models fit GPS velocities well, although they have significantly different tectonic implications. The accumulated strain along the Manila subduction zone at latitudes 15–19°N could be balanced by earthquakes with composite magnitudes of M_w 8.8–9.2, assuming recurrence intervals of 500–1000 years. GPS observations are consistent with full locking of the majority of active faults in Luzon to a depth of 20 km. Inferred moments of large inland earthquakes in Luzon fall in the range of M_w 6.9–7.6 assuming a recurrence interval of 100 years.