Double-Difference Tomography法による関東地方の3次元地震波速度構造およびフィリピン海プレートの形状の推定

• 弘瀬 冬樹

  気象研究所地震火山研究部

• 中島 淳一

  東北大学大学院理学研究科地震・噴火予知研究観測センター

• 長谷川 昭

  東北大学大学院理学研究科地震・噴火予知研究観測センター

書誌事項

タイトル別名

• Three-Dimensional Velocity Structure and Configuration of the Philippine Sea Slab beneath Kanto District, Central Japan, Estimated by Double-Difference Tomography
• Double Difference Tomographyホウ ニ ヨル カントウ チホウ ノ 3ジゲン ジシンハ ソクド コウゾウ オヨビ フィリピンカイ プレート ノ ケイジョウ ノ スイテイ

抄録

We estimated three-dimensional seismic velocity structure in and around the Philippine Sea plate subducting beneath the Kanto district in Japan by applying the double-difference tomography method to arrival time data of earthquakes obtained by the dense nationwide seismic network (Kiban-network). A low S-wave velocity and high V_p/V_s layer with several-km thick, which is shallowly inclined toward the subducting direction of the slab, has been clearly imaged. Comparison with the location of the upper surface of the Philippine Sea slab estimated from seismic refraction surveys, hypocenter distribution of relocated earthquakes, and focal mechanisms shows that this low S-wave velocity and high V_p/V_s layer corresponds to the crust of the Philippine Sea slab. Based on the presently obtained location of the low S-wave velocity and high V_p/V_s layer, hypocenter distribution, and focal mechanisms, we estimated the configuration of the upper surface of the Philippine Sea slab in the Kanto district. Presently estimated configuration of the Philippine Sea slab shows that the slab bends concavely and the depression is located eastward compared with those of the previous studies. Most of the earthquakes associated with the Philippine Sea slab occur along the plate boundary and/ or around the slab Moho. Prominent low S-wave velocity and high V_p/V_s layer was detected at depth of 30 km beneath the region along the latitude of 35.8 degrees, suggesting the serpentinization of the forearc mantle wedge due to dehydration of subducting slab.

収録刊行物

• 地震　第２輯

  地震　第２輯 60 (3), 123-138, 2008

  公益社団法人 日本地震学会

キーワード

• Double-Difference Tomography
• Philippine Sea slab
• Plate boundary
• Kanto district
• Central Japan

詳細情報

• CRID: 1390001204304147456
• NII論文ID: 10021093901
• NII書誌ID: AN00305741
• DOI: 10.4294/zisin.60.123
• ISSN: 18839029
• ISSN: 2186599X
• ISSN: 00371114
• NDL書誌ID: 9588010
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I9588010
• 本文言語コード: ja
• データソース種別:
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