ピリオドグラム解析による常時微動の卓越周期について : 第2報微動に及ぼす外乱の影響ならびに微動と地震動の観測例について

概要

論文の詳細を見る
Microseismic observations at a site (about 7 kilometer's from sea) in Hiratuka City were made for 24 hours continuously using seismometers with natural period of 1 second and 5 seconds. The purpose of this paper is to discuss the influence of disturbances (traffic quantity, sea waves) on microtremors at the site and also to investigate the relationship between the predominant period of long-period microtremors and seismic waves measured at the site. The following results were obtained. (1) The variations of amplitude of microtremors with time are in clear correspondence with those of the traffic quantity. But predominant periods of the microtremors obtained from periodogram analysis showed a constant value. (2) Variation of long-period microtremors amplitude with time obviously correlates with that of sea waves. (3) It is considered that predominant periods of the long-period microtremors are affected by sea waves, but the second predominant periods well agreed with the predominant periods of seismic waves.