Abstract:
Some digital seismic stations in Yunnan Province recorded low-frequency disturbances before two earthquake events occurred in Shangri-La County region of Yunnan Province. On august 10 th, 2013, before the two events, a super typhoon, Utor, formed to the southwest of the Guam in the Pacific Ocean. In this paper, we analyze the duration and spectral characteristics of these disturbances to find out whether the pre-earthquake low-frequency disturbances among the microtremors caused by the surge which was brought about by Utor. The result shows that they are high related to the track and intensity of Utor. These disturbances, whose dominant frequencies range between 0.15 Hz and 0.3 Hz, appeared approximately in accordance with Utor's landfall on the Chinese Continental Shelf.