Wang, Guoquan2017-06-222017-06-22August 2012015-08August 201http://hdl.handle.net/10657/1814This study investigated the current ground deformation that occurred along the east coastal region of China. Continuous measurements (2010-2014) from over 100 permanent GPS stations were analyzed. The GIPSY-OASIS software package (V6.3) is employed to obtain single receiver phase-ambiguity-fixed PPP solutions within a global reference frame (IGS08). To determine the magnitude and direction of local ground displacement over time, a Stable East China Reference Frame (SEChinaRF) was established using long-history data from five permanent GPS stations, which are evenly distributed along the China’s east coast and have continuously operated for at least 7 years. The realization of the SEChinaRF is defined in terms of a 14-parameter Helmert transformation from the International GNSS (Global Navigation Satellite System) Reference Frame of 2008 (IGS08). The PPP daily solutions achieved 2-4 mm horizontal accuracy and 7-8 mm vertical accuracy within SEChinaRF. The local reference frame is able to identify ground deformations at the level of 1mm/year. This study indicates that substantial land subsidence has been occurring in the Tianjin area with a steady subsidence rate of up to 45 mm/year during the past four years (2010-2014). The primary driving factor that caused the land subsidence was determined to be the excessive extraction of groundwater. Moderate subsidence (< 1 cm/year) was also observed in the east coastal regions such as Shanghai, Shandong and Guangdong. The GPS stations in eastern China also recorded significant co-seismic and post-seismic displacements induced by the 2011 Tohoku-Oki earthquake (MW 9.0) in Japan. This study indicated that the magnitude and direction of the co-seismic and post-seismic displacement depended on both the distance and azimuth to the earthquake source. The maximum co- and post-seismic (within 3 days after the mainshock) in China was recorded by a station in Changchun, which showed 21 mm horizontal displacement toward southeast. The post-seismic deformation is still occurring in the northeastern China region with a horizontal velocity of approximately 3 mm/year toward the earthquake epicenter. No considerable vertical co- and post-seismic displacements were observed. application/pdfengThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).GPSSubsidenceEast China2017-06-22Thesisborn digital