open access

https://hdl.handle.net/2115/67855

GRACE Seismology : Review and Perspective of Satellite Gravimetry for Earthquake Sciences

日本語

2017-01-10

日本地震学会

地震. 2輯

69(5)

69-85

The Gravity Recovery and Climate Experiment (GRACE) satellite system was launched in 2002, and has been playing important roles in various disciplines of earth and environmental sciences through measuring time-variable gravity field of the earth. It also offers a unique viewpoint to study earthquakes in terms of mass redistribution. We provide a review of earthquake studies with GRACE, e.g. basic facts of the satellite system and available data types, several kinds of non-earthquake gravity changes which may mask the earthquake-related signals. We also summarize past researches about co- and postseismic gravity changes. Two dimensional coseismic gravity changes were first observed with GRACE for the 2004 Sumatra-Andaman earthquake. After that, GRACE has caught coseismic gravity changes of the 2010 Maule, the 2011 Tohoku-oki, the 2012 Indian-ocean, and the 2013 Okhotsk deep-focus earthquakes. Such coseismic gravity changes are due mainly to two factors, i.e., the density changes around the fault edges, and the vertical deformations of boundaries with density contrasts such as the surface and the Moho. Short- and long-term postseismic gravity changes are considered to stem from afterslip and viscoelastic relaxation, respectively, but further studies are needed to quantitatively explain the observations.

学術雑誌論文

Version of Record

0037-1114

1883-9029