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Title:: Analysis of the Seismicity in North China Using Hybrid Probability Forecasting Model

Author(s):: MA Yong; BI Jinmeng; SONG Cheng; SHANG Xianqi; (Tianjin Earthquake Agency,Tianjin 300201,China)

Keywords:: probability forecasting model; effectiveness evaluation; characteristics of earthquake activity; North China

摘要:: 在可操作的地震预测研究过程中,构建效能可评价、符合区域地震活动特点的预测模型是至关重要的。以地震活动频发、地质结构复杂的华北地区为研究对象,选择相对强度模型、力矩比模型和简单平滑模型等3种地震概率预测模型,利用1970—2019年华北地区3.0级以上地震数据,以10 a为异常学习时段,以1 a为步长,分别开展1 a、3 a和5 a尺度下5.0级以上地震的回溯性滑动预测研究。通过Molchan图表法和T-test检验方法,对预测模型进行效能评估,优化了模型参数,确定了3种预测模型的最佳计算参数,构建了适合华北地区地震活动特点的不同时间尺度混合概率预测模型,并使用近10 a的地震分析了华北地区当前的地震活动特征。

Abstract:: For the “Operational Earthquake Forecasting”(OEF),it is critical to build a predictive model that conforms to the regional seismicity and whose effectiveness can be evaluated.In this paper,we select the M≥5.0 earthquake data from 1970 to 2019 in North China with complex geological structure and intensive earthquake activity,use the relative intensity(RI)model,the moment ratio(MR)model and the simple smoothing(Triple-S)model,carry out a retrospective sliding prediction of the historical M>5.0 earthquakes,during which we set the “learning period of earthquake anomalies ” as 10 years,step length as 1 year,and the scale of the retrospective cycle as 1,3 and 5 years.Then we use the Molchan Diagram method and the T-test method to evaluate the efficacy of the prediction model.We determined the best calculation parameters of the three prediction models by optimization,and constructed a “hybrid” of probability forecasting models on different time scales which is suitable for analyzing the characteristics of earthquake activity in North China.Then we apply the latest 10-year earthquake data to our model for the analysis of the current characteristics of earthquake activity in North China.