Gravity observations along the eastern margin of the Tibetan Plateau and an application to the Lushan M_S7.0 earthquake

This paper introducesrelative and absolute gravity change observations in the eastern portion of the Tibetan Plateau.We analyze and discuss a change that occurred in 2010 in the gravity along the eastern margin of the plateau and the relationship between this change and the 2013 Lushan M_S7.0 earthquake. Our results show that: (1) before the Lushan M_S7.0 earthquake, gravity anomalies along the eastern margin of the Tibetan Plateau changed drastically. The Lushan earthquake occurred at the bend of the high gradient zone of gravity variation along the southern edge of the Longmenshan fault zone. (2) The 2013 Lushan earthquake occurred less than 100 km away from the epicenter of the 2008 Wenchuan earthquake. Lushan and Wenchuan are located at the center of a fourquadrant section with different gravity anomalies, which may suggest that restoration after the Wenchuan earthquake may have played a role in causing the Lushan earthquake. (3) A medium-term prediction based on changes in gravity anomalies was made before the Lushan M_S7.0 earthquake, in particular, a prediction of epicenter location.