Crustal deformations associated with the great Sumatra-Andaman earthquake deduced from continuous GPS observation

• Hashimoto Manabu

  DPRI, Kyoto University

• Choosakul Nithiwatthn

  Department of Geology, Chulalongkorn University

• Hashizume Michio

  Department of Geology, Chulalongkorn University

• Takemoto Shuzo

  Geophysical Institute, Kyoto University

• Takiguchi Hiroshi

  Geophysical Institute, Kyoto University

• Fukuda Yoichi

  Geophysical Institute, Kyoto University

• Fujimori Kunio

  Geophysical Institute, Kyoto University

抄録

We analyzed continuous GPS data from more than 20 sites in Asia, Australia and islands in Indian Ocean in order to detect crustal deformations associated with the Sumatra-Andaman earthquake of December 26, 2004. Coseismic steps can be recognized at sites about 3, 000 km away from the epicenter such as Kunming in south China, Quezon in Philippines, and Diego Garcia Island in central Indian Ocean. The largest displacement of about 26 cm is found at Phuket in Thailand about 600 km away from the epicenter, about twice as large as that at Sampari, the nearest site in northern Sumatra. These observations suggest that as large slip as 14 m occurred beneath the Nicobar Islands. Large postseismic displacements are observed at Phuket and Sampari after the mainshock, but the former is three times larger than the latter. This suggests that the spatial distribution of afterslip is different from the coseismic slip distribution. The temporal variation of postseismic displacements can be explained by a logarithmic function derived from rate-state dependent friction law with short characteristic time. The area where coseismic displacements from the Nias earthquake of March 28, 2005 are detected is much smaller than that from the December mainshock, but displacement at Sampari is larger than that during the mainshock. These displacements suggest less than 4 m slip on a shallow dipping thrust fault and resultant moment release is smaller than that estimated from seismological data. Finally, total moment released by afterslip amounts to 3.83 × 10²² Nm which is equivalent to Mw 8.99 for about five months, including the afterslip for the Nias earthquake.

収録刊行物

• Ｅａｒｔｈ，　Ｐｌａｎｅｔｓ　ａｎｄ　Ｓｐａｃｅ

  Ｅａｒｔｈ，　Ｐｌａｎｅｔｓ　ａｎｄ　Ｓｐａｃｅ 58 (2), 127-139, 2006

  地球電磁気・地球惑星圏学会 、公益社団法人 日本地震学会、特定非営利活動法人 日本火山学会、日本測地学会、日本惑星科学会

キーワード

• Sumatra-Andaman earthquake
• Nias earthquake
• coseismic deformation
• postseismic deformation
• GPS
• fault model

詳細情報

• CRID: 1390001206511775872
• NII論文ID: 10024491091
• NII論文ID: 130003781142
• NII書誌ID: AA11211921
• DOI: 10.1186/bf03353369
• ISSN: 18805981
• ISSN: 13438832
• NDL書誌ID: 7857492
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I7857492
• Web Site: https://link.springer.com/content/pdf/10.1186/BF03353369.pdf
• Web Site: https://link.springer.com/article/10.1186/BF03353369/fulltext.html
• Web Site: http://link.springer.com/content/pdf/10.1186/BF03353369
• 本文言語コード: en
• データソース種別:
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  • NDL
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  • CiNii Articles
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