摘要
本文应用数字采样方法替代以往手工平滑尾波包络,分别处理了内蒙中部和新疆乌恰地区四个台站的可见模拟记录。通过对尾波衰减特征的测量,求得了这些地区尾波优势频率与延续时间、b(即πf/Q~*)与震级M和震级M与延续时间的经验关系式,估测了在参考频率1Hz附近的尾波Q值。本文就通过研究尾波Q来探索地壳内不均匀介质随时间的变化及其与地震发生的关系作了初步探讨。用单个地震求出的在平均优势频率附近的Q_4按尾波延续时间归一,随时间排列的归一Q_N均值就现有资料水平,除呼和浩特台在震后二月内略显偏低外,其他各台尚未发现明显变化。比较表明,同一地震不同分向估测的尾波Q值两者存在着差异。
This paper dealt with the visible analogue recordings at four stations in the middle of Inner Mongolia and Uqia area, Xinjiang Uygur Autonomous Region using the digital sampling method instead of the manual smoothing coda envelope. Through the measurement of the characteristics of the coda attenuation, we obtained empirical relations between coda predominant prequency and elapsed time, b(πf/Q) and magnitude M, as well as magnitude M and elapsed time in these areas, and we also estimated the coda Q value in the vicinity of reference frequency 1 Hz. Through the research on coda Q, this paper discussed the variations of the heterogeneous media in the crust with time and explored preliminarily its relation with the occurrence of earthquakes. The Qα around the average predominant frequency obtained from individual earthquake is normalized according to the coda elapsed time. The normalized QN average values arranged against the original time at all stations show obvious change except that at the Huhehuote station, where the value was slightly lower for two months after the earthquake. Their comparison shows that there exists difference among the coda Q values estimated by various components for the same earthquake.
出处
《地震》
CSCD
北大核心
1991年第6期31-41,共11页
Earthquake
基金
地震学联合基金
