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dc.contributor.authorHydrographic Survey Team of Hokkaido-Nansei-Oki Earthquake
dc.date.accessioned2020-02-04T01:30:42Z
dc.date.available2020-02-04T01:30:42Z
dc.date.issued1994
dc.identifier.urihttp://hdl.handle.net/1834/16038
dc.description.abstractThis paper describes the results of sea bottom survey in the source region of the 1993 Hokkaido Nansei-Oki Earthquake (off Southwest Hokkaido). The earthquake, of magnitude 7. 8 occurred in the Japan Sea off southwest Hokkaido fom 12 July 1993 and caused severe damage on the Okusiri Island and southwest Hokkaido. The Hydrographic Department of Japan has conducted topographical, geological and geophysical surveys by the survey vessel ”Mei yo” from 22 to 26 July 1993. The survey items are topographical survey by narrow multi-beam echo sounder (Sea Beam 2000) ,seismic profiling by an airgun, geomagnetic and gravity survey. The average coverage of seabeam swath survey in the survey area is about 90%. The survey revealed the following tectonic features in the source region. (1) A number of well developed faults and lineaments trending mainly NE-SW or NW-SE are recognized on the Okusiri Ridge. Okusiri Ridge is block faulted by these tectonic lines.These tectonic lines might be activated by this earthquake. (2) Detail bathymetry shows thrust movement caused by EW compressional stress distributes in the Japan Basin. (3) Topographical features typical to landslide are found on the slope of the Okusiri Ridge. Some of them might be probably caused by this earthquake. (4) A seamount having a caldera-like depression of 5 km diameter at its summit is recognized in the eastern edge of the Japan Basin. (5) A group of small knolls are recognized in the area from western slope of the Okusiri Ridge to the Japan Basin. They resemble to the Fukaura Knoll Chain in the source region of 1983 Nihonkai-Chubu Earthquake.en_US
dc.language.isojaen_US
dc.relation.urihttps://www1.kaiho.mlit.go.jp/GIJUTSUKOKUSAI/KENKYU/report/rhr30/rhr30-12.pdfen_US
dc.titlePreliminary results of the survey on the source region of the Hokkaido-Nansei-Oki earthquake.en_US
dc.typeJournal Contributionen_US
dc.bibliographicCitation.issue30en_US
dc.bibliographicCitation.titleReport of Hydrographic and Oceanographic Researchesen_US
dc.description.statusPublisheden_US
dc.format.pagerangepp.395-412en_US
dc.type.refereedRefereeden_US
refterms.dateFOA2021-01-30T18:48:36Z


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