Study on earthquake swarm standard and its prediction significance in Qinghai region
Due to the active occurrence of small and medium earthquakes and the significant enhancement of regional monitoring capabilities in Qinghai,using the national unified criteria for earthquake swarms has resulted in an excessive number of swarms. This makes it difficult to effectively distinguish their predictive significance and determine whether they should be extracted as anomalies. Therefore,it is urgent to establish a new regional earthquake swarms criteria suitable for the characteristics of Qinghai seismic activity. The paper aims to use the catalog of small and medium earthquakes in Qinghai since 1980 as the research object. Based on the earthquake swarm criteria recommended by the national seismology team,previous research results,regional seismic characteristics,forecast efficiency evaluation,and multiple tests,we propose new regional criteria for earthquake swarms with better predictive efficiency. According to the new criteria,only ML≥3.0 earthquake are selected in Qinghai,and we incorporate this new screening method into daily work to provide reliable judgment bases for earthquake tracking. In addition,by analyzing the annual frequency of earthquake swarms before M ≥ 6.5 earthquakes in Qinghai and its adjacent areas since 1980,it was found that there is a significant increase in earthquake activity of ML ≥ 2.0 one to two years before major earthquakes,indicating a certain temporal predictive significance for M≥6.5 earthquakes in the region.
Qinghai regionearthquake swarm activitiesprediction efficiencypredictive index
万方数据
维普
