Near-field surface deformation during the April 20, 2013, Ms7. 0 Lushan earthquake measured by 1-Hz GNSS

Abstract

The April 20, 2013, M s7. 0 Lushan earthquake was successfully recorded by closely spaced Continuous Global Positioning System (CGPS) stations owned by the Crustal Movement Observation Network of China (CMONC). The 1-Hz GNSS data from eight CGPS stations, which are located between 30 km and 200 km from the hypocenter, were processed within quasi-real-time. The near-field surface deformation indicated the following characteristics: the near-field movements were limited to several centimeters; the peak of the deformation wave was significantly larger than the static permanent offset; at the beginning of the event, the north wall of the fault moved to the southeast as the south wall moved to the southwest; station SCTQ, which was the closest station to the hypocenter at 30 km, had the largest static permanent displacement of 2 cm; the peaks of the deformation waves were 1. 5 cm, 5 cm and 3 cm, to the east, the south and vertically upward, respectively ; and the peaks of velocity and acceleration, derived from the deformation, were 3. 4 cm/s and 5. 3 cm/s 2 , respectively.