Total Geomagnetic Survey on Suruga Bay, on the Pacific cost, Shizuoka, Japan, the second series report.

Abstract:

In 2009 to 2014, total geomagnetic and geological surveys by School of Marine Science & Technology, Tokai University, were conducted on Suruga Bay, located on the Pacific coast of Honshu in Shizuoka Prefecture, central Japan, where a large thrust earthquake, often referred to as the Tokai earthquake, has been supposed to occur soon (Ishibashi, 1981). Suruga Bay area, where the Philippine Sea plate subducts beneath Japan, had some local magnetic anomalies on the overriding plate side. The past investigation of ship-borne survey conducted in Suruga Bay area is geomagnetic anomaly data of the Hydrographic Department of the Maritime Safety Agency in 1997.

Detailed geomagnetic surveys carried out in the Suruga Bay area, is 50 km x 35km in S-N and W-E, respectively. Total geomagnetic anomaly values range from +100nT to +600nT.

In this report, we carried out newly geomagnetic survey lines which costal region on Suruga Bay. The following results were found.

(1) The costal region of Izu Peninsula in Northern part of Izu-Ogasawara arc is indicated high geomagnetic anomaly. This cause is regarded as something to come near to some volcanos.

(2) And costal region of the Fujigawa fault system in the Sourath Fossa Magna region is indicated high geomagnetic anomaly.

We present features of total geomagnetic anomalies on and around Suruga Bay with the results of inversion.