1. Geological implications of the 0212 earthquake in 2014 at the Tatun Volcano Group of Taiwan: Synergistic effects of volcanic and faulting activities
- Author
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Che-Min Lin, Min-Hung Shih, Ya-Chuan Lai, Cheng-Horng Lin, Li-Chin Chang, Yi-Heng Li, Hsin-Chieh Pu, and Chih-Wen Kan
- Subjects
geography ,Focal mechanism ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Seismic zone ,Geology ,Fault (geology) ,010502 geochemistry & geophysics ,01 natural sciences ,Volcano ,Geothermal fluid ,Group (stratigraphy) ,Upper crust ,Aftershock ,Seismology ,0105 earth and related environmental sciences ,Earth-Surface Processes - Abstract
On February 12, 2014, an ML 4.2 earthquake (named 0212 EQ) occurred at the Tatun Volcano Group (TVG) in northern Taiwan. Seismic data from both the regional broadband array in Taiwan and a local dense seismic network in the TVG indicate that the 0212 EQ was located at a depth of 4.3 km near Shamoshan, one of the latest eruptive units in the TVG. Referring to the aftershocks surrounding the 0212 EQ, we further found that (1) they formed a linear seismic zone dipping ∼50° towards the southeast to reach the Shanchiao Fault that cuts through the TVG, (2) focal mechanism of more than half of the larger aftershocks (MD ≥ 1.5) matched this linear seismic zone for a normal faulting, and (3) the seismic b-value was calculated to be 3.55. They are used to delineate the geometry of the Shanchiao Fault at the upper crust and to infer that localized geothermal fluid might have affected the activity of aftershocks as manifested by the very high seismic b-value. The strongly compensated linear vector dipole of the centroid moment tensor suggests the 0212 EQ had a non-double-couple source resulted from the gravitational collapse. Thus, we conclude that the 0212 EQ was a combined synergistic effect of a collapsed reservoir filled with volcanic fluids and faulting activities along the Shanchiao Fault.
- Published
- 2017