地震 第2輯
Online ISSN : 1883-9029
Print ISSN : 0037-1114
低周波地震のスケーリングモデル
津波地震と中小規模低周波地震の関係
武村 雅之小山 順二
著者情報
ジャーナル フリー

1983 年 36 巻 3 号 p. 323-336

詳細
抄録

Classification of low-frequency earthquakes has been made quantitatively by using a diagram of seismic-moment factor Me versus characteristic period Tc. Tc and Me correspond to period of corner frequency and seismic-moment density at Tc of each earthquake. About 3, 000 earthquakes from 1926 to 1978 along the Kurile, Japan, and Ryukyu trenches have been analyzed and MS's of those earthquakes cover the range from 3 to 8.3. Most of earthquakes beneath the inner trench slopes have been classified into low-frequency events which show large Tc for the same Me, while ordinary earthquakes have been commonly found in the frontal arc regions. Relations among magnitudes and seismic moment: MS-MJMA, MS-mb, and MS-Mo, for low-frequency events are also different from those for ordinary events. The relations, therefore, cannot be explained by a scaling model for ordinary earthquakes. A scaling model has been derived for low-frequency earthquakes in a statistical manner, taking into account constraints based on the relations among magnitudes and seismic-moment mentioned above. Corner frequencies of source spectra of the low-frequency model are always one half of those of the ordinary model with the same seismic-moment. This model has been also justified by the data of so called tsunami earthquakes in other subduction regions in the world, suggesting a similarity relation among destructive tsunami earthquakes and low-frequency earthquakes with small magnitude.

著者関連情報
© 社団法人日本地震学会
次の記事
feedback
Top