巻号一覧
61 巻 (2015)
- 3 号 p. 157-
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61 巻, 1 号
選択された号の論文の4件中1～4を表示しています
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坪井賞受賞記念論文
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伊藤 武男2015 年 61 巻 1 号 p. 1-15
発行日: 2015/06/30
公開日: 2016/07/28
ジャーナル フリーWe observe various phenomena in the surface layers of the crust, such as earthquakes, volcanoes, geological features and so on. In order to understand these phenomena, it is important to consider an interaction between the lithosphere and asthenosphere. In this paper, I introduce three studies: 1) Asthenospheric density and elastic moduli are derived from ocean tidal loads response. We have developed a new method with a new concept for estimating underground structure using GNSS data set. The new method has possibility of providing new information for lithosphere and asthenosphere. 2) We obtain spatiotemporal distribution of interplate coupling during an earthquake cycle using long-term geodetic data. The model considers an interaction between the lithosphere and asthenosphere, such as viscoelastic response due to the coseismic slip on the plate interface. 3) We established the Aceh GNSS Network for the Sumatran Fault System (AGNeSS) across a segment that has not experienced a major earthquake in at least 170 years. We inferred fault locking depth and shallow creep along this segment from AGNeSS. The accumulated seismic moment corresponds to an earthquake of magnitude 7.
These studies reveal that geodetic survey is powerful tool for understanding the internal structure of the Earth and Geodynamics. Geodetic observation covers a wide frequency range that overlaps the seismic frequency band. In the future, geodetic methods for short and long time scales will fuse to seismological method, and geological or geomorphological methods, respectively. Geodesy will combine the different time scales of geodynamic studies.抄録全体を表示PDF形式でダウンロード (1185K) -
佐藤 まりこ2015 年 61 巻 1 号 p. 17-34
発行日: 2015/06/30
公開日: 2016/07/28
ジャーナル フリーThis paper summarizes the author's research on positioning precision of GPS/acoustic seafloor geodetic technique and observed seafloor movements off northeastern Japan before and associated with the M9.0 earthquake on March 11, 2011. In regard to the former, it is shown that positioning precision has been greatly improved by the introduction of the sailing observation with a hull-mounted system in 2008, compared with the drifting, uncontrollable way as before. The repeatability for the sailing observation is about 2 cm in the horizontal component and better at the seafloor reference points along the Nankai Trough than those along the Japan Trench. Besides, the precision of height determination has also been improved, though it is still inferior to that of horizontal positioning. In regard to the latter, spatio-temporal change of seafloor crustal movements off northeastern Japan has been detected, based on observation data for about nine years before the 2011 event. Particularly, off Miyagi Prefecture, a series of crustal movements indicating strain accumulation-release process has been observed. Interplate coupling off Miyagi Prefecture during interseismic periods was relatively weaker since 2007 than before 2005, while interplate coupling off Fukushima Prefecture was significantly weaker than that off Miyagi Prefecture. Furthermore, from the observations before and after the 2011 event, the huge co-seismic displacements of up to 24 m have been observed just above the focal region.抄録全体を表示PDF形式でダウンロード (6699K)
報告
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橋本 実奈2015 年 61 巻 1 号 p. 35-36
発行日: 2015/06/30
公開日: 2016/07/28
ジャーナル フリーPDF形式でダウンロード (563K)
書評
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鷺谷 威2015 年 61 巻 1 号 p. 37-38
発行日: 2015/06/30
公開日: 2016/07/28
ジャーナル フリーPDF形式でダウンロード (582K)
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