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Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Science / Faculty of Science >
北海道大学地球物理学研究報告 = Geophysical bulletin of Hokkaido University >
第81号 >
GNSS観測に基づく2016年熊本地震（M7.3）の余効変動時系列解析による九州地方の粘性構造の推定
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| Title: | GNSS観測に基づく2016年熊本地震（M7.3）の余効変動時系列解析による九州地方の粘性構造の推定 |
| Other Titles: | Viscosity distribution beneath the Kyushu Island estimated by GNSS postseismic time series of the 2016 Kumamoto earthquake (M7.3) |
| Authors: | 不破, 智志1 Browse this author | | 大園, 真子2 Browse this author |
| Authors(alt): | FUWA, Satoshi1 | | OHZONO, Mako2 |
| Issue Date: | 19-Mar-2018 |
| Publisher: | 北海道大学大学院理学研究院 |
| Journal Title: | 北海道大学地球物理学研究報告 |
| Journal Title(alt): | Geophysical bulletin of Hokkaido University |
| Volume: | 81 |
| Start Page: | 45 |
| End Page: | 55 |
| Abstract: | In order to investigate the viscosity distribution beneath the Kyushu Island, we analyzed postseismic time series of Global Navigation Satellite System induced by the 2016 Kumamoto earthquake（M7.3） . For the ～1.5 years of daily coordinates at 135 GEONET stations, we fitted theoretical time evolutions with two approaches.（1） Assuming that the first 50-days is dominated by the afterslip, we applied both of logarithmic and exponential functions. For the estimation, we firstly found the appropriate common time decay constants for the afterslip（0.996 days） , then estimated other parameters.（2） Ignoring first rapid afterslip signals, we fitted only exponential function for the time series after 50-days. As a result, both approaches indicate 1017-1020 Pa s of viscosity in the Kyushu Island. Especially, low viscosity of ～1018 Pa s was obtained around the central region of Kyushu. This corresponds to the location of low viscosity in the lower crust. Therefore, the estimated viscosity distribution is probably affected by the beneath of the viscoelastic structure through the lower crust to the surface. |
| Rights: | http://creativecommons.org/licenses/by-nc/4.0/ |
| Type: | bulletin (article) |
| URI: | http://hdl.handle.net/2115/68478 |
| Appears in Collections: | 北海道大学地球物理学研究報告 = Geophysical bulletin of Hokkaido University > 第81号
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