Strong Ground Motion in the Source Region of the 1984 Western Nagano Prefecture Earthquake. Inferred from Displaced Boulders.

Iio Yoshihisa, Yoshioka Katsuhei

doi:10.4294/jpe1952.40.407

Strong Ground Motion in the Source Region of the 1984 Western Nagano Prefecture Earthquake. Inferred from Displaced Boulders.

DOI 被引用文献1件

Iio Yoshihisa

Abuyama Observatory, Research Center for Earthquake Prediction, Disaster Prevention Research Institute, Kyoto University
Yoshioka Katsuhei

Abuyama Observatory, Research Center for Earthquake Prediction, Disaster Prevention Research Institute, Kyoto University

書誌事項

タイトル別名

Inferred from Displaced Boulders

抄録

Boulders displaced by the 1984 Western Nagano Prefecture Earthquake (M_JMA=6.8) were investigated mainly in the eastern part of the source region which had not been fully surveyed. It was found that numerous boulders were displaced over the large extent of the eastern part of the source region. It is inferred that the boulders were not displaced by high-frequency seismic waves with frequencies between 5-10 Hz, but by low-frequency seismic waves of about 1 Hz, which radiated from the smooth dislocation on the fault plane. The boulder which experienced the largest ground motions was discovered in the eastern part. The ground motions estimated from the displacement of the boulder have a velocity of 5.5 m/s and an acceleration of 3.5 g in the vertical direction, and a velocity of 3.2 m/s and an acceleration of 2.0 g in the horizontal direction.