衛星通信を利用した口永良部島火山における地磁気全磁力連続観測

Abstract

近年水蒸気爆発が繰り返されてきた口永良部島火山の山頂部において、2000年8月より地磁気全磁力観測を行っている。火山性地震の震源域で熱消磁が起こった場合を想定して観測点を選定し、データは、オーブコムという衛星通信を利用して研究室へ転送している。今のところ火山活動に起因すると考えられるような変動は捉えられていないが、通信に関しては100%成功しており、小型・軽量・省電力のオーブコム通信を火口近傍の観測に利用する目処がたった。

Variations of geomagnetic total intensities have been measured since August 2000 around the summit crater of Kuchierabujima volcano where phreatic eruptions were repeatedly occurred. The measurement sites were determined so as to detect the change in total intensity due to thermal demagnetization at hypocentral zone of volcanic earthquakes. The observed data are transferred to the office at Sakurajima through satellite telecommunication service called orbcomm. No volcanomagnetic effect has been observed by now. Data transfer via the orbcomm service has been perfectly working, which suggests that this concise system with a small lightweight body and low power consumption could be utilized for observations close to the active crater.