[S03-P] Poster

[S03-P-10] Seismic velocity variation within the Tatun Volcano Group, Northern Taiwan, from ambient noise analysis

^○Ya-Chuan Lai^{1, 2}, Cheng-Horng Lin^{1, 2}, Hsiao-Fen Lee^1,2, TVO Team^1,2 (1.Institute of Earth Sciences, Academia Sinica, Taiwan, 2.Taiwan Volcano Observatory at Tatun)

The Tatun Volcano Group (TVG) locates in the north part of Taiwan, where is only 15 km away from the downtown Taipei. Thus, the monitoring for the potential activity of volcano is required for geohazard assessment. Up to now, more than forty broadband seismic stations have been installed in the TGV area to monitor the micro-earthquakes and the specific singles related to hydrothermal system. Such dense seismic network with long-term continuous seismic data would provide the information to study the temporal or spatial change of properties of the TGV. In the study, we use correlation of ambient noise between stations to determine the temporal variation among 2013 to 2015. The seismic velocity variations show comparable pattern with the anomalies of geochemical observations related to ML 4.0 Shilin earthquake. Significant velocity reduction was observed by the nearby interstation path and HCl concentration rapidly increased. Additionally, we also compared the temporal/spatial seismicity with the velocity variation.