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Interseismic deformation and moment deficit along the Manila subduction zone and the Philippine Fault system
Author(s) -
Hsu YaJu,
Yu ShuiBeih,
Loveless John P.,
Bacolcol Teresito,
Solidum Renato,
Luis Artemio,
Pelicano Alfie,
Woessner Jochen
Publication year - 2016
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2016jb013082
Subject(s) - subduction , geology , seismology , trench , fault (geology) , slip (aerodynamics) , trough (economics) , forearc , tectonics , layer (electronics) , thermodynamics , chemistry , physics , macroeconomics , organic chemistry , economics
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.