| dc.description.abstract | The Taipei Metropolis with a population of more than 7 million is economic and political center of Taiwan. Shanchiao Fault within this Metropolis is considered as to be an active fault. Thus, if its associated earthquake struck, Taipei Metropolis might result in great loss.
The Shanchiao Fault, located along the western margin of Taipei basin, is an east-dipping normal fault with left-lateral component. On top of the fault is covered in Quaternary unconsolidated sediments. Its length is estimated over 40 km. According to the drilling data in Taipei Basin, there is an elevation difference of at least 700 m on tops of the tertiary basement across the fault. It indicates that Shanchiao fault’s movement related to the formation of Taipei Basin and implies that under present extensional regime of northern Taiwan, Shanchiao fault may be activated in the future.
In this study, I apply triangular dislocation to calculate the surface settlement and estimate possible flood areas assuming the activation of Shanchiao fault. The results show if the seismic moment-magnitude of associated earthquake reaches 7.5, the maximum settlement is over 3 m. Under this settlement, possible flood area at Taipei Basin reaches 50 km2, and possible sea water encroachment area approaches 2 km2 at Jinshan. According to updated information, Shanchiao fault might be extended east-northward close to Huaping Isle, Thus, the fault length could be more than 80 km, and the possible generated seismic moment-magnitude approaches 8. In such a case, the maximum settlement could reach 5 m and almost all areas of Taipei Basin and Jinshan coasts would be flooded.
I also calculate Coulomb Failure stresses (CFS) on neighboring faults. The results show the CFS has high dependence on earthquake’s hypocenter, most of maximum CFS on these neighboring faults are sense of strike-slip and the status of the induced stress is not favored in an extensional regime of northern Taiwan in short, these neighboring faults are un-likely to be triggered by a reactivation of Shanchiao fault.
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