1998 Fiscal Year Final Research Report Summary
Tectonics of the southeastern Philippine Sea using GPS
| Project/Area Number |
09041096
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Field Research |
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| Research Field |
固体地球物理学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KATO Teruyuki University of Tokyo, Earthquake Research Institute, Associate Professor, 地震研究所, 助教授 (80134633)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUSHIMA Takeshi Kyushu University, Faculty of Science, Research Associate, 理学部, 助手 (40222301)
KOTAKE Yoshihiko University of Tokyo, Earthquake Research Institute, Research Associate, 地震研究所, 助手 (60012944)
NAKAO Shigeru University of Tokyo, Earthquake Research Institute, Research Associate, 地震研究所, 助手 (90237214)
VAMACHO Juan T. Emergency Management Office, Commonwealth of the Northern Mariana Islands, Researcher, 研究員
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| Project Period (FY) |
1997 – 1998
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| Keywords | GPS / Northern Mariana / Philippine Sea / plate / back-arc spreading |
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| Research Abstract |
In order to investigate the instantaneous motion of the Mariana arc, we have conducted twice of the GPS obserbation in the Northern Mariana Islands in 1998 and 1999 following the first occupation in 1992 and 1994. We have conducted four day sessions in January-February of 1998 and February of 1999 using seven Trimble 4000SSE GPS receivers. The results were analyzed using the Bernese Ver. 0.0 baseline analysis software togeher with 1994 data. Results suggests that the islands are moving toward east relative to the main Philippine Aes plate. Estimated velocities at each islands are ; 10.4mm/yr with N113E for Agrihan, 20.0mm/yr with N70E for Pagan1 20.9mm/yr with N73E for Guguan, 40.0mm/yr with N75E for Anatahan, 40.3mm/yr with N83E for Saipan, and 50.8mm/yr with N93E for Guam, respectivery. Thus estimated velocities may represent the velocity of back-arc spreading at the Mariana trough. It would be worthy to note that the velocity is larger and move eastward when we go to southern islands. This may suggest how is the back-arc spreading at present time.
Although our research was successfully conducted, we may have to consider the followings. 1) we should conduct GPS surveys for the islands further north because these islands are not yet re-occupied, which is important to clarify how far the back-arc is reaching to north. 2) we should repeat surveys for all of these islands considering that many of islands are volcanic so that the monitoring of local deformation of these islands are important in terms of volcanic hazard reduction.
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Research Products
(8 results)
