Quasi-Real Time Determination of 2013 Lushan Mw 6.6 Earthquake Epicenter, Trigger Time and Magnitude Using 50 Hz GPS Observations

摘要

50 HZ Global Positioning System (GPS) high rates data of 8 Continual Operation Reference System (CORS) sites nearby Lushan are used to analyze the earthquake trigger time, epicenter and magnitude. All sites position time series on N, E directions are resolved with the track software, and horizontal accuracy can reach to 2 cm at least. Horizontal position time series analyses show that the earthquake mainly affects QLAI, SCTQ, YAAN sites, the horizontal peak amplitudes can reach to 50 mm, the maximum instantaneous velocity can reach to 72.36 mm/s and the maximum instantaneous acceleration have reached to 105.9 mm/s~2. Analyzing the position time series by the method of S transformation, the arrival time of seismic wave is estimated. With seismic wave arriving time and coordinates of three sites which are first detecting the seismic wave, the earthquake's epicenter and trigger time can be fast determined by three-dimensional search method. Moreover, the earthquake magnitude can also be estimated by horizontal peak amplitudes from the sites using the regression method. These suggest exiting GPS infrastructure could be developed into an effective component of earthquake assessment.