Publication Date:
1996-01-01
Description:
Dense gravity measurements were carried at with the Fast Static GPS positioning along 5 survey lines across the Rokko fault system. The Bouguer anomaly was calculated to estimate the underground structure relevant to the 1995 Hyogo-ken Nanbu earthquake. All the Bouguer anomaly profiles are characterized by flat areas on the Rokko Mountains and Kobe Plain, with steep gradient between them. The gradient is most likely due to the fault scarps between the Rokko granite and the sedimentary layer of the Osaka and Kobe groups. It also indicates that the faults are vertical or reverse ones, at least just below their surface traces. This finding is consistent with the tectonic background of the Rokko Mountains that have upheaved under the east-west compression in the Quaternary. Moreover, the southwestward extension of the Koyo Fault underneath the sedimentary layer was found. The extension runs on the edge of the earthquake disaster zone.
Print ISSN:
0022-3743
Electronic ISSN:
1884-2305
Topics:
Geosciences
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