A THERMAL SIMULATION STUDY ON VOLCANIC ACTIVITY ALONG BASHI SEGMENT OF TAIWAN-LUZON ISLAND ARC

The thermal numerical simulation for island arc volcanic activities is not only an important aspect of the study on tectono-thermal evolution of a subduction zone, but also a critical method to verify the results of field observation. In this study, based on geological and geophysical conditions, we selected the Camiguin active volcano in the east volcano chain (EVC) and the Calayan extinct volcano in the west volcano chain (WVC) along the Bashi Segment of the Taiwan-Luzon island arc as our models.Thermal simulations using finite-element numerical method were conducted. During the simulations, we first calculated the present heat flow distribution above the Camiguin active volcano and Calayan extinct volcano, and then analyzed the divergence of the two volcanoes. The simulation results show, from the top of the Camiguin active volcano to 30 km away, the heat flow obviously rises and becomes higher with acceleration when it comes closer to the top of the volcano where the heat flow can reach 310 mW·m^-2. However, the heat flow on the top of the Calayan extinct volcano and surroundings only rises a little. The heat flow increment increases slowly from below 3 mW·m^-2 40 km away from the volcano to 15 mW·m^-2 on the top of the volcano.