Outer trench slope extension to frontal wedge compression in a subducting plate

Abstract The occurrence of faulting in subducting plates is a major process that changes the mechanical properties lithosphere and carries surface materials into mantle wedges. Two ocean-bottom seismometer networks deployed on frontal accretionary wedge northern Manila trench 2005 outer slope 2006 were used to detect earthquakes plate. All available P S manually picked phases waveforms 16 short-period, three-component stations used. Relocation was performed using double-difference method with differential times derived from phase-picked data. intraplate earthquake sequences small-to-moderate magnitudes subduction system investigated this study. results revealed distinct fault planes, but contrasting seismogeny over Trench. seismicity (as measured 2005) mainly contributed by fluid overpressure sequence, whereas incoming plate 2006) aftershocks an extensional sequence. obtained seismic velocity models V p / s ratios likely caused high pore-fluid pressure within shallow zone. By near-field waveform inversion algorithm, we determined focal mechanism solutions for few relatively large earthquakes. Through use data global observations, stress transfer may be responsible activity study area during period 2005–2006. In late 2005, interface unlocked effect due thrusting-dominant This event changed regime across Trench triggered normal extension at mid-2006. However, present study, hybrid solution indicating reverse strike–slip mechanisms implemented, it locked again 2006. Graphical