珊溪水库地震震后趋势的快速判定

2002年7月28日珊溪水库库区发生了M_L3.5地震,之后记录到M)L≥1.0地震50余次,最大地震是9月5日M_L3.9地震。7月28日M_L3.5地震发生后,应用“跟踪式后续地震的模糊预测方法”进行了震后趋势跟踪预测。首先,选用多个地震序列资料作为样本,按预测要求,确定震级大小的分类标准,构成分类矩阵,然后,计算每个序列的6项地震活动性指标构成样本矩阵,而用刚刚发生的地震序列构成待判矩阵,应用一种模糊软聚类方法进行判断,得到未来某一时间段内将发生的地震震级属于哪一类。如果使用几个时间段资料、对不同预报期分别建立几组样本矩阵和分类矩阵,则可实现跟踪式震后趋势快速预测。对9月5日M_l3.9地震和震后趋势预测比较准确。本文简单介绍了预测方法和预测效果。

Rapid Judgement of Post-Seismic Tendency of Shanxi Reservior Earthquake

The Shanxi reservior is located in the Wenzhou city of Zhejiang province, the dam height and the storage of this reservoir are 138. 4 m and 1432 million m3 respectively. A reservoir-induced earthquake ML 3. 5(July 28,2002) took place in this reservior area. Afterwards, more than 50 aftershocks(ML≥1. 0) have been recorded in this area. The earthquake ML 3. 9 occurred in September 5,2002 is the most strong earthquake of the sequence. Soon after the significant earthquake ML 3. 5 occurred, we were doing rapid follow-up prediction for the post-seismic tendency applying the fuzzy soft cluster method after the occurrence of significant earthquake. At first, some data of earthquake sequences should be selected as samples to determine the classification standard of earthquake magnitude in accordance with the demand of prediction, and build the classification matrix. Then, the 6 seismicity indexes of every sample sequence and the latest earthquake sequence are calculated to build the sample matrix and the wait-judge matrix respectively. By judging these data with application of fuzzy soft cluster, it can be known which class of earthquake will take place in some term of future. If sample matrix and classification matrix for different prediction terms are built with data of different time section, the rapid prediction of follow-up post-seismic tendency will be achieved. The prediction of the ML 3. 9 and the rapid judgement of post-seismic tendency were relatively precise. In this article, this method of prediction and its effects are introduced briefly.