１９９５年奄美大島近海（喜界島近海）地震の地震活動とテクトニクス　沈み込む海山と１９９５年奄美大島近海地震のテクトニクス的解釈

• 笠原 順三

  東京大学地震研究所

• 佐藤 利典

  東京大学地震研究所

書誌事項

タイトル別名

• the 1995 Amami-Oshima-Kinkai (Kikai-jima-Kinkai) Earthquake and Its Tectonics. A Subducting Seamount and Its Tectonic Influence to the 1995 Amami-Oshima-Kinkai Earthquake.
• シズミコム カイザン ト 1995ネン アマミ オオシマ キンカイ ジシン ノ

抄録

The 1995 Amami-Oshima-Kinkai Earthquake occurred near the Nansei-Shoto Trench where the upheaval area of the Philippines Sea plate subducts beneath the Nansei-Shoto islands. The main shock was M_JMA 6.6 and its largest aftershock was M_JMA 6.5. The aftershock distribution for these two events by Yamada et al. (1996) corresponds to two distinct and nearly vertical fault zones. The focal mechanisms obtained by Kikuchi (1996) are consistent to the aftershock distribution.<BR>The authors propose that the seamount found beneath the trench-continental-slope indirectly triggered this earthquake activity. If a subducting oceanic plate is normal oceanic denser than an overriding island arc, the oceanic plate should be faulted near vertically priori to the plate subduction by horizontally tensional force due to plat bending. On the other hand, an oceanic plate with seamounts or an oceanic plateau lighter than a normal oceanic plate, might resist to plate subduction due to its small density and delaying normal faultings might occur in the subducting oceanic plate. The delaying normal faultings between a subducting seamount and a preceding normal portion of the oceanic plate can compensate the subduction process. The compressional convergence margin such as the Nankai Trough, however, may not generate such normal faultings due to the nature of stress field.<BR>The low seismicity area existing across the trench axis is also seen both in this aftershock activity and ISC hypocenters. This is the same result as those in other regions. This might imply low earthquake potential for this portion of plate interface due to the existence of low density sediments and water contained in the sediments.

収録刊行物

• 地学雑誌

  地学雑誌 106 (4), 557-566, 1997

  公益社団法人 東京地学協会

キーワード

• 1995年奄美大島近海地震
• 沈み込む海山
• 正断層型
• プレート内地震
• 海溝軸付近の低地震帯

詳細情報

• CRID: 1390001204229782912
• NII論文ID: 10002236313
• NII書誌ID: AN00322536
• DOI: 10.5026/jgeography.106.4_557
• ISSN: 18840884
• ISSN: 0022135X
• NDL書誌ID: 4283312
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4283312
• 本文言語コード: ja
• データソース種別:
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  • NDL
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  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可