1986 年伊豆大島噴火にともなった地殻上下変動と重力変化とについての補足的考察

概要

論文の詳細を見る
Every volcano would manifest particular activities whenever it erupts. It is rather difficult to presume patterns of the future activity but it is hopeful to find any tendency of possible activities. In this respect, any empirical laws deduced from the past activities of various volcanoes should be useful for appreciation of the progressing activities. First, empirical laws for deformations and gravity changes on volcanoes are proposed, and referring to these laws, elevation and gravity changes associated with the 1986 eruption of Ooshima volcano are discussed. The subsidence observed along the route of precise levels on the northern slope of the volcano may have been caused by magma intrusions thereabout while the subsidence observed along the route in the southeastern part induces doubts as to its volcanic origin ; the latter may have been probably due to earthquake vibrations of the ground. A possible distribution of elevation changes is presented : the changes are composed of a tilt of the island as a whole and a local depression on the northern slope. Generally, gravity would change in relation to ground deformations with the progress of volcanic activities. To discriminate any significant gravity changes associated with the 1986 eruption of Ooshima volcano, the gravity changes are plotted against the elevation changes : they have a poor correlation each other. This suggests that their origins are differently located. The gravity changes may be attributable to local changes superposed on those due to a tilt of the island as a whole. If more bench marks were effectively distributed on the volcano, we should have detected local gravity changes of volcanic origin, if any, more clearly.
特定非営利活動法人日本火山学会の論文
1988-06-30

1986 年伊豆大島噴火にともなった地殻上下変動と重力変化とについての補足的考察

スポンサーリンク

概要

著者

関連論文

スポンサーリンク