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ID 13915
Eprint ID
13915
FullText URL
Thumnail ESR_4_1.pdf 898 KB
Title Alternative
Three-dimensional structure of P wave velocity in the crust and upper mantle beneath southwest Japan
Author
Tanaka, Takashi
Abstract
Trevel-time data of the P wave were inverted to study three-dimensional structure of the P wave velocity in the upper mantle and crust beneath the Shikoku and Chugoku districts, southwest Japan. Low-velocity and high-velocity regions were found in the upper crust of the eastrn and western regions in the Shikoku district, respectively. The activity of crustal earthquakes is high in the eastern region. Moreover a significant high-velocity region exists in the uppermost mantle, where the activity of small earthquakes is very high. A low-velocity region with velocity of 7.0km/s was found just above the descending Philippine Sea plate with high velocity of 8.0 km/s. This region is continued to oceanic crust in the vicinity of the Nankai trough and its velocity is nearly equal to the P wave velocity (6.7 km/s) of oceanic crust. Thus the low velocity is interpreted as the oceanic crust. A high-velocity region is found below the depth of 50km in the Shikoku district. This region suggests the Philippine sea plate lying horizontally from the Shikoku districts to the ocast of the Seto Inland Sea of the Chugoku district. A low-velocity zone suggesting the volcanic front is found around the depth of 50km at the coast of the Japan Sea of the Chugoku distrit.
Keywords
Three-dimenrsional structure
P wave
Crust
Upper mantle
Philippine Sea plate
Published Date
1997-09-20
Publication Title
Okayama University Earth Science Report
Publication Title Alternative
岡山大学地球科学研究報告
Volume
volume4
Issue
issue1
Publisher
岡山大学理学部地球科学教室
Publisher Alternative
Department of Earth Sciences Faculty of Science, Okayama University
Start Page
1
End Page
20
ISSN
1340-7414
NCID
AN10506284
Content Type
Departmental Bulletin Paper
language
日本語
Copyright Holders
岡山大学地球科学研究報告編集委員会
File Version
publisher
Refereed
False
Eprints Journal Name
esr