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Long- and short-term postseismic gravity changes of megathrust earthquakes from satellite gravimetry
| Title: | Long- and short-term postseismic gravity changes of megathrust earthquakes from satellite gravimetry |
| Authors: | Tanaka, Yusaku Browse this author | | Heki, Kosuke Browse this author →KAKEN DB |
| Keywords: | postseismic gravity changes | | viscoelastic relaxation | | afterslip | | GRACE | | seismic cycle | | subduction zone |
| Issue Date: | 16-Aug-2014 |
| Publisher: | American Geophysical Union |
| Journal Title: | Geophysical Research Letters |
| Volume: | 41 |
| Issue: | 15 |
| Start Page: | 5451 |
| End Page: | 5456 |
| Publisher DOI: | 10.1002/2014GL060559 |
| Abstract: | Using monthly satellite gravimetry data, we studied time-variable gravity field after three M9 class earthquakes, the 2004 Sumatra-Andaman, 2010 Chile (Maule), and 2011 Tohoku-oki earthquakes. The observations showed that the gravity typically (1) decreases coseismically, (2) continues to decrease for a few months, and (3) increases over a longer period. Therefore, postseismic gravity changes have two components with different time constants and polarities. The mechanisms of short- and long-term postseismic gravity changes are not as clear as coseismic changes at the moment, but might be explained to some extent with afterslip and the Maxwell viscoelasticity, respectively. These two components are difficult to discriminate with surface velocity measurements because the forearc area moves trenchward at both stages. They appear in different polarities in gravity, making satellite gravimetry a unique tool to separate them. |
| Rights: | Copyright 2014 American Geophysical Union. |
| Type: | article |
| URI: | http://hdl.handle.net/2115/58017 |
| Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 日置 幸介
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