Short-impending Anomaly of GPS Observation and its Implications in Yunnan Earthquake Predication

Abstract:

This study proposals a new method, short-impending anomaly of GPS (SIA-GPS), to predict the coming earthquake. Based on long-term GNSS observations, we observed the abnormal deformations occurred around the active faults in Yunnan area before the earthquakes of magnitude M_W³5.0. We constructed the regional strain fields with networks filtering, and extracted the abnormal deformations of each grid before each strong coming earthquake. Such special deformations of the GNSS observation are able to serve for short-impending earthquake prediction. The SIA-GPS method includes three steps. Firstly, Yunnan region is divided into multiple grids using interpolation calculation，and the uniform displacement field is created. The area velocity field is obtained based on the continuous GNSS observations using GAMIT/GLOBK software. Next, the earthquake response capacity of each grid is evaluated in time-series analysis focusing on strains, and the short-term anomalies are easily extracted. Lastly, all the abnormal signals are carefully diagnosed in the considerations of tectonic movements. As examples, we predicated 19 earthquakes using the (SIA-GPS) method. 14 earthquakes of them are successful within the tolerable special and time misfits, and 5 of them do not occurred. The code of predication for short-impending earthquake requires that all the coming earthquakes of Mw³5 must be predicated, the maximum time error for coming event is three months, and the corresponding spatial misfit allows 5 grids. Following this role, 14 earthquakes of Mw³5 are predicted using SIA-GPS indicators with success rate 73.6%. For such experiences, SIA-GPS method has been utilized as a benefit tool to predicate the potential coming earthquakes in Earthquake Administration of Yunnan Province.

Keywords：Short-impending anomaly of GPS, SIA-GPS, time series of analysis, GNSS observation, earthquake prediction, surface deformation, strain, Yunnan area.