Kinematics of the tectonic blocks and active faults at the post-orogenic stage: Northern Taiwan

Northern Taiwan offers a rare opportunity to quantify the rate and style of deformation in the transition zone, from the collision in the southeast, subduction, rifting, to orogenic collapsing in the northwest. The updated GPS velocity field collected from 2002 to 2014 and leveling vertical velocity field from 2004 to 2010 were inverted by a 3-D block model in this study to infer the tectonic block rotations and fault slip rates in reference to the Eurasian plate. Our optimized modeling results show that the clockwise rotation rate of 20.8° ± 2.8°/Myr in the Hualien block is caused by the coupling of the waning arc-continent collision between the Luzon volcanic arc and the Eurasian plate, and the northeastward migration of the block toward the Ryukyu trench. In Ilan domain, the rapid clockwise motion was derived at a rate of 34.9° ± 65.9°/Myr in southern part of the plain. We proposed that the rapid clockwise rotation results from the asymmetry rifting at the southwestward extension of the Okinawa trough. An another new key finding is highlighted in the capability of maximum magnitude ∼6.2 is indicated on the Suao and the Choshui faults in the Ilan plain.