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Sea bottom gravity survey of Osaka bay and its study; Osakawan kaitei juryoku chosa to sono kosatsu

Abstract

This paper reports a sea bottom gravity survey conducted with an objective to identify deep underground structure in the vicinity of the epicenter of the Hyogoken-Nanbu Earthquake. The surveyed areas are the whole Osaka Bay area north of the north latitude of 34 degrees and 20 minutes, and the eastern part of the Sea of Harima east of the east longitude of 134 degrees and 40 minutes, excluding the areas difficult of performing measurements. A square lattice with sides each about 2 km was arranged with 408 measurement points. The measurement was carried out by using an observation vessel mounted with a sea bottom gravimeter made by LaCoste and Romberg Corporation, which was lowered down to the sea bottom at the measurement points. Errors in positions and water depths at the gravity measuring points were suppressed to less than 0.002 minutes and 0.1 m, respectively. The measurement data were given necessary corrections by using a unified method applicable also to land areas, and a Bouguer anomaly chart was prepared. Based on the chart, this paper summarizes features in the Bouguer anomaly in the surveyed areas (such as the low-gravity anomaly band extending the central part of the Osaka bay from  More>>
Authors:
Komazawa, M; [1]  Ota, Y; Shibuya, S; Kumai, M; Murakami, M [2] 
  1. Geological Survey of Japan, Tsukuba (Japan)
  2. Japex Geoscience Institute, Inc., Tokyo (Japan)
Publication Date:
May 01, 1996
Product Type:
Conference
Report Number:
CONF-9605233-
Reference Number:
SCA: 580000; PA: NEDO-96:913524; EDB-96:173346; SN: 96001687131
Resource Relation:
Conference: 94. SEGJ (The Society of Exploration Geophysicists of Japan) Conference, Butsuri tansa gakkai dai 94 kai (1996 nendo shunki) gakujutsu koenkai, Tokyo (Japan), 15-17 May 1996; Other Information: PBD: May 1996; Related Information: Is Part Of Proceedings of the 94th SEGJ (The Society of Exploration Geophysicists of Japan) Conference; PB: 475 p.; Butsuri tansa gakkai dai 94 kai (1996 nendo shunki) gakujutsu koenkai koen ronbunshu
Subject:
58 GEOSCIENCES; GRAVITY SURVEYS; SEA BED; SHIPS; SUBSURFACE STRUCTURES; GEOLOGIC FAULTS; DENSITY; ROCK BEDS; EARTHQUAKE FOCI; GEOLOGIC SURVEYS
OSTI ID:
395567
Research Organizations:
Society of Exploration Geophysicists of Japan, Tokyo (Japan)
Country of Origin:
Japan
Language:
Japanese
Other Identifying Numbers:
Other: ON: DE97709027; TRN: 96:913524
Availability:
Available from The Society of Exploration Geophysicists of Japan, 2-18, Nakamagome 2-chome, Ota-ku, Tokyo, Japan; OSTI as DE97709027
Submitting Site:
NEDO
Size:
pp. 430-434
Announcement Date:
Dec 02, 1996

Citation Formats

Komazawa, M, Ota, Y, Shibuya, S, Kumai, M, and Murakami, M. Sea bottom gravity survey of Osaka bay and its study; Osakawan kaitei juryoku chosa to sono kosatsu. Japan: N. p., 1996. Web.
Komazawa, M, Ota, Y, Shibuya, S, Kumai, M, & Murakami, M. Sea bottom gravity survey of Osaka bay and its study; Osakawan kaitei juryoku chosa to sono kosatsu. Japan.
Komazawa, M, Ota, Y, Shibuya, S, Kumai, M, and Murakami, M. 1996. "Sea bottom gravity survey of Osaka bay and its study; Osakawan kaitei juryoku chosa to sono kosatsu." Japan.
@misc{etde_395567,
title = {Sea bottom gravity survey of Osaka bay and its study; Osakawan kaitei juryoku chosa to sono kosatsu}
author = {Komazawa, M, Ota, Y, Shibuya, S, Kumai, M, and Murakami, M}
abstractNote = {This paper reports a sea bottom gravity survey conducted with an objective to identify deep underground structure in the vicinity of the epicenter of the Hyogoken-Nanbu Earthquake. The surveyed areas are the whole Osaka Bay area north of the north latitude of 34 degrees and 20 minutes, and the eastern part of the Sea of Harima east of the east longitude of 134 degrees and 40 minutes, excluding the areas difficult of performing measurements. A square lattice with sides each about 2 km was arranged with 408 measurement points. The measurement was carried out by using an observation vessel mounted with a sea bottom gravimeter made by LaCoste and Romberg Corporation, which was lowered down to the sea bottom at the measurement points. Errors in positions and water depths at the gravity measuring points were suppressed to less than 0.002 minutes and 0.1 m, respectively. The measurement data were given necessary corrections by using a unified method applicable also to land areas, and a Bouguer anomaly chart was prepared. Based on the chart, this paper summarizes features in the Bouguer anomaly in the surveyed areas (such as the low-gravity anomaly band extending the central part of the Osaka bay from north-east to south-west, and the gradient structure existing on the Awaji island side). 6 refs., 1 fig.}
place = {Japan}
year = {1996}
month = {May}
}