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Report on a characteristic oscillation about 38 mHz (26 s) in northeastern Japan following surface wave of the 2011 Tohoku megathrust earthquake
| Title: | Report on a characteristic oscillation about 38 mHz (26 s) in northeastern Japan following surface wave of the 2011 Tohoku megathrust earthquake |
| Authors: | Mitsui, Yuta Browse this author →KAKEN DB | | Heki, Kosuke Browse this author →KAKEN DB |
| Keywords: | Satellite geodesy | | Transient deformation | | Broad-band seismometers | | Surface waves and free oscillations | | Asia |
| Issue Date: | Jul-2015 |
| Publisher: | Oxford University Press |
| Journal Title: | Geophysical Journal International |
| Volume: | 202 |
| Issue: | 1 |
| Start Page: | 419 |
| End Page: | 423 |
| Publisher DOI: | 10.1093/gji/ggv147 |
| Abstract: | We try to detect an unidentified signal from the surface motion at northeastern Japan immediately after the 2011 Tohoku earthquake. A focused frequency range is 10-100 mHz (10-100 s). We find a peaky signal with frequency of about 38 mHz (26 s) based on the horizontal-to-vertical (H/V) spectral ratio using the high-rate GNSS data at 382 GEONET stations. We are not able to identify locality of the signal. The signal appears several minutes after the passing of surface wave fronts. The duration of the signal is about 2 min. Since the origin of the 38 mHz signal is unlikely to be local hydrologic tremors, tectonic tremors, or the tsunami, we speculate that the 38 mHz signal originates from a kind of a characteristic oscillation of Northeastern Japan triggered by the 2011 Tohoku earthquake. A normal-mode simulation implies that high-order radial overtones could create the signal with a spherically-layered velocity structure, however, the detailed mechanism of the signal still remains a mystery. |
| Rights: | This article has been accepted for publication in "Geophysical Journal International" © The Authors 2015. Published by Oxford University Press on behalf of The Royal Astronomical Society. |
| Type: | article |
| URI: | http://hdl.handle.net/2115/58577 |
| 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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