地震研究

根据华东地区的地震活动特点,定义较简单的半径搜索方法,遵循一定的准则挑选出1976年以来华东地区满足震前累积应变加速释放模型(ASR)的14次M_L≥4.5地震序列。将“破裂—时间分析”法的非线性方程分成两个线性方程,采用线性最小二乘法拟合参数k/m与主震矩的经验关系,确定华东地区的ASR模型,并用来预测主震的时间和震级。经检验该方法预测震级误差约为±0.3,发震时间误差约±1.68 a。

According to the characteristics of seismic activity in East China, we define a simple approach of searching radius and choose fourteen M_L≥4.5 earthquake sequences since 1976 in East China which satisfy the pre-seismic Accelerating Strain Release(ASR)model. We express the nonlinear time-to-failure analysis equation with two linear equations and fit the empirical relation between the coefficient k/m and the main seismic moment tensor by means of Linear Least Square method in order to construct ASR model of East China for the prediction of the time and magnitude of the main shock in East China. Comparing the magnitude and the original time from the ASR model with the ones of the occurred strong shocks, we find that the magnitude error is ±0.3 and the time error is ±1.68 years.

引言
1 “破裂—时间分析”方法的基本原理
2 资料及数据处理
3 结论与讨论

图1 1970～2010年华东地区地震震级—频度分布图(实线是ML≥2.3地震的震级—频度线性拟合)<br/>Fig.1 Magnitude frequency distribution from 1970 to 2010 in East China region(solid line:linear fitting of magnitude frequency of ML≥2.3 earthquake)

图1 1970～2010年华东地区地震震级—频度分布图(实线是ML≥2.3地震的震级—频度线性拟合)
Fig.1 Magnitude frequency distribution from 1970 to 2010 in East China region(solid line:linear fitting of magnitude frequency of ML≥2.3 earthquake)

图2 研究区内满足ASR模型的ML≥4.5地震震中分布<br/>Fig.2 Distribution of epicenters of ML≥4.5 earthquake satisfying ASR model in study region

图2 研究区内满足ASR模型的ML≥4.5地震震中分布
Fig.2 Distribution of epicenters of ML≥4.5 earthquake satisfying ASR model in study region

图3 搜索半径的对数与主震震级MS的关系(实线表示拟合结果)<br/>Fig.3 The relationship between logarithm of search radius and the magnitude MS of main shock(solid line:the fitting result)

图3 搜索半径的对数与主震震级MS的关系(实线表示拟合结果)
Fig.3 The relationship between logarithm of search radius and the magnitude MS of main shock(solid line:the fitting result)

图4 系数k/m与主震矩M0之间的关系<br/>Fig.4 The relationship between the coefficient k/m and the seismic

图4 系数k/m与主震矩M0之间的关系
Fig.4 The relationship between the coefficient k/m and the seismic

表1 华东地区满足ASR模型的14次地震序列的主震参数及拟合结果<br/>Tab.1 Fitting result and main shock parameters of 14 earthquake sequences satisfying with ASR model in East China region

表1 华东地区满足ASR模型的14次地震序列的主震参数及拟合结果
Tab.1 Fitting result and main shock parameters of 14 earthquake sequences satisfying with ASR model in East China region

图5 华东地区4次地震的CBS均方根误差等值线图(a)1977-07-09,ML4.6;(b)1983-11-07,ML4.6; (c)1992-01-23,ML5.6;(d)1997-04-01,ML4.5<br/>Fig.5 RMS error contour of CBS of 4 earthquakes in East China region

图5 华东地区4次地震的CBS均方根误差等值线图(a)1977-07-09,ML4.6;(b)1983-11-07,ML4.6; (c)1992-01-23,ML5.6;(d)1997-04-01,ML4.5
Fig.5 RMS error contour of CBS of 4 earthquakes in East China region

图6 华东地区4次地震的CBS加速释放曲线(a)1977-07-09,ML4.6;(b)1983-11-07,ML6.2; (c)1992-01-23,ML5.6;(d)1997-04-01,ML4.5<br/>Fig.6 Accelerating release curve of CBS of 4 earthquakes in East China region

图6 华东地区4次地震的CBS加速释放曲线(a)1977-07-09,ML4.6;(b)1983-11-07,ML6.2; (c)1992-01-23,ML5.6;(d)1997-04-01,ML4.5
Fig.6 Accelerating release curve of CBS of 4 earthquakes in East China region

表2 华东地区14个主震事件用ASR模型的回溯性预测结果<br/>Tab.2 Retrospective predicted result for 14 main shocks using ASR model in East China region

表2 华东地区14个主震事件用ASR模型的回溯性预测结果
Tab.2 Retrospective predicted result for 14 main shocks using ASR model in East China region

图7 预测时间(a)、预测震级(b)与实际值偏差(中心实线表示平均偏差,外部虚线表示2倍标准差)<br/>Fig.7 Deviations between the predicted time(a)、predicted magnitude(b)and actual value(the solid line represents the mean deviation,the dashed lines represent twice of standard deviation)

图7 预测时间(a)、预测震级(b)与实际值偏差(中心实线表示平均偏差,外部虚线表示2倍标准差)
Fig.7 Deviations between the predicted time(a)、predicted magnitude(b)and actual value(the solid line represents the mean deviation,the dashed lines represent twice of standard deviation)

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备注

引言

1 “破裂—时间分析”方法的基本原理

2 资料及数据处理

3 结论与讨论

期刊信息