A midcrustal ramp‐fault structure beneath the Taiwan tectonic wedge illuminated by the 2013 Nantou earthquake series
- Resource Type
- Authors
- Ray Y. Chuang; Long-Chen Kuo; Yih-Min Wu; Kaj M. Johnson; Kuo En Ching
- Source
- Geophysical Research Letters. 40:5080-5084
- Subject
- Stress drop
Tectonics
Geophysics
Mountain formation
Fault plane
Coseismic slip
General Earth and Planetary Sciences
Slip (materials science)
Wedge (geometry)
Seismology
Geology
Aftershock
- Language
- ISSN
- 1944-8007
0094-8276
[1] Taiwan’s active mountain belt is a spotlight for orogenic studies and was first used to test the critical-taper wedge mechanics. The concept of an orogenic wedge above a shallow detachment surface has been highly influential on current understanding of orogenic processes in Taiwan. However, the recent ML 6.2 and ML 6.5 2013 Nantou reverse-faulting earthquakes in central Taiwan have nucleated below the proposed detachment, indicating that active mountain building is occurring below the orogenic wedge. We estimate the coseismic slip distributions and fault geometry using the uniform stress drop slip inversions. The earthquakes occur on essentially the same 30° dipping fault plane ramping up from ~20km depth near a cluster of 1999 Chi-Chi earthquake aftershocks to the shallow detachment and the Chi-Chi fault plane. The fault could be a deep extension of a mature shallow fault or a newly developed deep ramp fault that is not reflected in the surface geology.