3:00 PM - 4:00 PM
[S04-P-05] Numerical reconstruction of the source rupture and strong ground motions of the 1935 Hsinchu-Taichung Earthquake, Taiwan from historical triangulation data
On 21 April 1935, a large earthquake with a local magnitude of 7.1 struck central Taiwan, named the Hsinchu-Taichung earthquake. It was the most destructive earthquakes in Taiwan history since 1600. This event was associated with two major faults: the northern one as the Shihtan reverse fault, and the southern one as the Tuntzuchiao right-lateral strike-slip fault. To understand its possible rupture history of the associated faults, and its potential impact to Taiwan of a destructive earthquake of this kind, we reconstructed the possible source characteristics and the strong ground motions of the 1935 Hsinchu-Taichung earthquake using historical triangulation data as the reference. There are three main types of fault model for this event, as two previously proposed fault models and a combined model. We investigated the spatial slip distribution based on these models from source inversion by using the triangulation data that is in the time of 1917-1937. In comparison to about 60 stations of the triangulation data, we chose a best model for a scenario for ground motion simulation by Spectral-Element Method (SEM). The preferred (best fit) inversion result suggested that this earthquake was composed of four fault-segments, as two observed surface rupture faults to the north by reverse faulting and to the south by strike-slip motion, and with two blind faults without surface rupture in between. We also compared the spatial slip distribution, the synthetic ShakeMap, and the historical intensity distribution for various scenarios to examine the possible hazard from the reconstructed source model. Results from this study suggested that the multiple fault-segments might rupture from adjacent fault segments with different styles of faulting.