1994 Fiscal Year Final Research Report Summary
On the Relation between Seismic Gap and Volcanos in Quaternary
| Project/Area Number |
05452075
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体地球物理学
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| Research Institution | TOTTORI UNIVERSITY |
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Principal Investigator |
NISHIDA Ryohei Tottori Univ., Facul.of General Education, Professor, 教養部, 教授 (90027269)
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| Co-Investigator(Kenkyū-buntansha) |
UMEDA Yasuhiro Kyoto Univ., Disast.Prev.Res.Inst., Associate Professor, 防災研究所, 助教授 (10025421)
SHIOZAKI Ichiro Tottori Univ., Facul.of General Education, Associate Professor, 教養部, 助教授 (80221290)
MIYAKOSHI Junichiro Tottori Univ., Facul.of General Education, Professor, 教養部, 教授 (60032116)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Seismic Gap / Tectonic Stress / East area of Shimane Pref. / Migration / PxP Wave / Low Conductivity Anomaly |
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| Research Abstract |
It is being whached that a seismic gap locate on East area of Shimane Pref.. Becouse we have observed the high seismic activity around the area, and two large Quaternary composite volcanos situate both side. They are Mt.Daisen and Sanbe. Their eruptive activities began in middle Pleistocene and continued until recently. On the latest seismic activity, two earthquake, M5.3 in 1977 and M6.1 in1978, occurred near Sanbe volcano where locate the west side of aseismic area, and have continuted high activity at present. On its east side, we observed a migration of seismic activity along a seismic zone in San'in Pref., the coast of Japan Sea. The 1983 Tottori earthquake, M6.2 is the largest in this area since the Tottori earthquake M7.2 in 1943. It has a paticular pattern of a aftershock distribution to take the form of %. A shock of M4.9 with many aftershocks and rumbles occurred in 1985 at aaseismic area where locate near Daisen volcano. Since 1989 a large swarm has been occurred at the west of Daisen volcano, which five shocks are more than M5. they are M5.3 and M5.4 in Oct.1989, and M5.1, and M5.1 in Nov.1990. In 1991, a earthquake of M5.9 occurred in west area apart from shock of 1989, about 15km at distance. Their fault Plane solutions were predominantly left rateral strike slip faults. The migration advanced from east to west along the active zone as the same volcanic zone in this area, toward the seismic gap. And we observed low conductivity anomaly zones under Sanbe.
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