A GPS Study on Observing Earthquake Ground Displacement

Abstract

Taiwan is located on the boundary between the Eurasian and Philippine Sea Plates. An average motion as high as six cm per year near the boundary has been reported. Earthquake and crustal deformation activities are very high every year. The main purpose of this study is to apply the GPS technique to observe the ground surface motions due to earthquakes. Firstly, the fiducial-site approach was applied to obtain the change between site positions before and after an earthquake. Secondly, the kinematic GPS (KGPS) method is used to obtain time-to-time estimates and to extract the time history of the displacements with a much faster data sampling rate of one second. Two GPS data sets from two earthquake events have been processed. The GPS approaches are capable of detecting surface motions due to earthquakes. The fiducial-site method with daily observation is able to monitor permanent or steady-state site position changes while the KGPS approach with one-second result allows transient response to be estimated.