Presenter: Hui-Lun Chiang
Date: 2016/10/20
Abstract
The Gravity Recovery and the Climate Experiment (GRACE) is a twin satellite has been improving our knowledge on time-variable mass distributions on the Earth. The applications in the devastating 2004 Sumatra-Andaman event and its companion Nias earthquake on 2005 are feasible for us to look into the details of coseismic undulation and the following postseismic recovery. In Ogawa et al. [2007], they focus on figuring out what drove the relaxation of coseismic dilatation and compression. Combining a model which calculates postseismic geoid uplift and GRACE gravity data, the authors suggest that the self-healing system is caused by the diffusion of supercritical H 2 O in the upper mantle. As for the research of Einarsson et al. [2010], they are interesting in separating the effects of coseismic geoid depression and postseismic rebound of the Sumatra-Andaman event apart from Nias earthquake. They also conduct a slip model compared to GRACE data which end up removing the modelled Nias effect from the GRACE-derived data successfully. These two studies let people understand the specific characteristics of the coseismic and postseismic which lead much more future researches.
Reference
Ogawa R., and Heki K. (2007) Slow postseismic recovery of geoid depression formed by the 2004 Sumatra-Andaman Earthquake by mantle water diffusion. Geophysical Research Letters, VOL. 34, L06313.
Einarsson I., Hoechner A., Wang R., and Kusche J. (2010) Gravity changes due to the Sumatra-Andaman and Nias earthquakes as detected by the GRACE satellites: a reexamination. Geophysical Journal International, 183, 733–747