[G03-5] Solid-Earth and other applications

[G03-5-05] Seismic gravity changes of the 2004 Sumatra-Andaman earthquake and static gravity anomaly

^○Yusaku Tanaka, Kosuke Heki (Hokkaido University, Hokkaido, Japan)

The 2004 Sumatra-Andaman earthquake is the first very large earthquake after the launch of the GRACE satellites in 2002. In this study, we analyzed the time series of the gravity changes using the latest GRACE data sets. The result suggests that the postseismic gravity changes of the 2004 Sumatra-Andaman earthquake have almost ended. The observation data can help us determine time scales of the postseismic gravity changes and constrain viscosity structure of the upper mantle. Moreover, it may allow us to research interseismic gravity changes because the static gravity anomaly is formed by the repeat of inter-, co-, and postseismic gravity changes and the static anomaly and co- and postseismic gravity changes are being revealed.