Using natural earthquakes as sources in the seismic refraction method for studying the upper mantle structure, an ocean-bottom seismometer array observation was performed in the western Northwest Pacific Basin in the summer of 1981. This observation revealed that the apparent surface velocity of P-waves refracted from the lower-lithosphere was observed as 8.4 km/sec in the epicentral distances of 7°-9°. The true velocities at their turning points (depth level 60-100km) were about 8.3km/sec. The existence of 8.4-8.5km/sec (apparent velocity) layers at the top of the lower-lithosphere appears to be a general feature not only beneath the continental shield regions but also beneath the old ocean basins. Such a P-wave velocity supports the garnet-pyrolite model for the mineralogical composition of the lower-lithosphere.
雑誌名
東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo
巻
61
号
3
ページ
403 - 414
発行年
1987-02-10
ISSN
00408972
書誌レコードID
AN00162258
フォーマット
application/pdf
日本十進分類法
453
出版者
東京大学地震研究所
出版者別名
Earthquake Research Institute, University of Tokyo
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P-wave Velocity in the Lower-Lithosphere in the Western Northwest Pacific Basin Observed by an Ocean-bottom Seismometer Long Range Array
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