祁连山构造带中强地震前广义前震活动探讨

Preliminary Study on the Generalized Foreshocks in Qilianshan Tectonic Zone

摘要:

分析了祁连山构造带1984年以来的13次中强地震(MS≥5.3),其中有广义前震的10次,占77%。广义前震与主震优势间隔时间3个月,优势空间距离约300~400 km,震级差在1级以上。中强地震前广义前震沿构造带似呈有序分布;同一地区中强震之前广义前震空间分布图像具有一定相似性。广义前震的有序活动可视为祁连山构造带中强地震发生的短临异常。

Abstract:

13 moderate-strong earthquakes occurred in Qilianshan tectonic zone [Ms≥5.3） since 1984 are analyzed. Among them 10 events （about 77%） occurred with generalized foreshocks. The predominant time interval between generalized foreshocks and mainshock is about 3 months with a predominant spatial distance in 300-400 km, and the magnitude difference is over 1. Before moderate-strong earthquakes occurred, the generalized foreshocks show the orderliness distribution along the tectonic belt, and the images in different area has certain similarity. The orderliness distribution of generalized foreshock may be taken as a short-term and imminent anomaly before the impending moderate-strong earthquake in Qilianshan tectonic zone.