道東地域の地磁気永年変化と三成分絶対測量

DOI HANDLE Web Site オープンアクセス

書誌事項

タイトル別名
  • Geomagnetic secular changes in eastern Hokkaido
  • ドウトウ チイキ ノ チジキ エイネン ヘンカ ト サン セイブン ゼッタイ ソクリョウ

この論文をさがす

抄録

Localized geomagnetic secular changes have been reported in the eastern Hokkaido, previously by repeat surveys, and more recently, by continuous recording. Some previous studies discuss the piezo-magnetic field due to stress accumulation by plate subduction. To elucidate the nature of such “anomalous” secular changes in the total field, we started geomagnetic three-component absolute measurements. Firstly, we estimated the so-called orientation effect which may be contained in the simple differential total field, by using the results of the absolute measurements. At some stations this effect has been found to be non-negligible. 　　While correcting the orientation effect, we assessed an effect of global-scale secular changes by using the IGRF-11 model. This effect contributes much to regional-scale secular changes in the eastern Hokkaido. As a result, considerable part of the observed differential total field can be explained by this component. Then, residuals which deviated from the global secular field are obtained, which showed relatively good agreement with the predicted piezo-magnetic field. However, it is still uncertain that the residual field is significant or not, as well as its origin. 　　Our analysis has also revealed an “anomalous” decreasing trend in the total field in the late 90s at NIB station which is located at the eastern side of Kussharo caldera. We speculate that this anomalous magnetic change may have some relation to the elevated signature of volcanic unrest at Atosanupuri where seismic swarm was followed by significant ground deformation in the mid 90s.

収録刊行物

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ