STUDY ON GRAVITY ANOMALY OF PROFILE RIWOQE-YUSHU-MADUO
Yang Guangliang 1,2,3) ;Shen Chongyang 1,2) ;Sun Shaoan 1,2) ; Tan Hongbo 1,2) ; Xuan Songbai 1,2) ; and Li Zhejun 1,2)
1)Institute of Seismology, China Earthquake Administration, Wuhan 4300712)Crustal Movement Laboratory,Wuhan 4300713)Geodynamics Laboratory, College of Earth Sciences, Graduate University of CAS, Beijing 100039
Abstract Yushu Ms7.1 earthquake occurred in the Bayan Har block, exactly the GanziYushu fault zone. We set up a relative gravity survey lines cross the fault zone and conducted the gravity survey. We processed the raw data, such as atmospheric correction, polar motion correction, drift correction, adjustment calculation, and then obtained the free air anomaly of the profile. After the curvature correction, flatpanel and highprecision terrain correction by using the ASTER GDEM (2009) Digital terrain model (1 ″× 1″), we obtained a complete profile of the probe Bouguer gravity anomaly. The results show that the location of faults which consistents with the geological results as their is a sudden change zone in the Bouguer anomaly curve; the basement begins to uplift from the place near Yushu to its northeast along the profile, and the maximum rate is at Qingshuihe town. We have concluded that it is resulted from the Indian crust subducting and inserting, making the eastern edge of QinghaiTibet Plateau uplifting.
