Earthquake-induced gravitational potential energy change in the active Taiwan orogenic belt

Abstract

The Philippine Sea Plate is converging against the Eurasian Plate near Taiwan at a velocity of 7-8 cm yr-1; this has caused the Taiwan orogenesis and induced abundant earthquakes. In this study we examine the corresponding change of gravitational potential energy (ΔGPE) using 757 earthquakes from the earthquake catalogue of the Broadband Array in Taiwan for Seismology (BATS) from 1995 July to 2003 December. Our results show that the variation of the crustal ΔGPE strongly correlates with the different stages of the orogenesis. Except for the western Okinawa Trough and southern Taiwan, most of the Taiwan convergent region exhibits a gain of crustal ΔGPE. In contrast, the lithospheric ΔGPE in the Taiwan region exhibits a reverse pattern. For the whole Taiwan region, the earthquake-induced crustal ΔGPE and the lithospheric ΔGPE during the observation period are 1.03 × 1017 J and -1.15 × 1017 J, respectively. The average rate of the whole ΔGPE in the Taiwan region is very intense and equal to -2.07 × 1010 W, corresponding to about 1 per cent of the global GPE loss induced by earthquakes. © 2005 RAS.