地震研究

云南地震预警站网监测效能评估

朱杰,钟玉盛

(云南省地震局,云南昆明 650224)

关键词：噪声水平; 地震预警; 监测能力; 时效性; 混淆矩阵

Evaluation of the Monitoring Capability of the Yunnan Earthquake Early Warning Network

ZHU Jie,ZHONG Yusheng

(Yunnan Earthquake Agency,Kunming 650024,Yunnan,China)

Keywords：noise level; earthquake early warning; monitoring capability; timeliness; confusion matrix

DOI: 10.20015/j.cnki.ISSN1000-0666.2025.0044

备注

摘要

全文

图/表

参考文献

选取2023年每个月中没有地震记录、人工干扰较小且记录完整的某一天的地震背景噪声数据,计算得出云南地震预警站网包含的3类地震仪器的噪声最大概率峰值位移(PGD)分布,并选择这3类地震仪器噪声最大的一个月(2月)对云南地震预警站网效能进行全面评估。利用考虑时效性的传统测震站网监测能力评估方法和混淆矩阵方法对云南地震预警站网3类地震仪器单独组网和融合组网的预警最小震级、预警首报时间和预警系统触发阈值进行研究。结果显示,测震仪、强震仪和烈度仪的PGD范围分别为0.004～0.048 μm、0.04～2.85 μm和 7.5～26.9 μm。云南地震预警站网监测能力下限由测震仪单独组网决定,平均值为M_L1.3,三网融合预警最小震级平均值为M_L2.7,云南55%的地区的预警最小震级小于M_L3.0,95%的地区小于M_L3.4。预警首报时间平均值为5.2 s,55%的地区小于5.1 s,95%的地区小于5.8 s。对于云南地震预警系统,提高其站点分布密度,一定程度上能够降低预警最小震级下限和减少预警首报时间。云南地震预警系统的触发阈值为M_L3.0,能满足实际站网监测工作需求,系统准确度为0.779 7,精确度为0.895 5,灵敏度为0.759 5,特异性为0.820 5,F1分数为0.821 9。

To study the warning effectiveness of the Yunnan Earthquake Early Warning Network,this paper selects the complete records of noise data of one day in each month of 2023,which has no earthquakes and less interference.The distribution of the peak ground displacement(PGD)of the three types of sensors is calculated,and the month(February)with the highest noise of the three types of sensors is chosen to conduct a comprehensive assessment of the warning network.By using the traditional monitoring capacity assessment method of seismic networks that considers timeliness and the confusion matrix method,this paper studies the minimum warning magnitude,the first report time after an earthquake,and the trigger threshold of the warning system for the three types of sensors when they are independently networked and in a combined network within the Yunnan Earthquake Early Warning Network.The results revealed that PGD of the seismometers' sensors ranged between 0.004-0.048 μm,PGD of the accelerographs' sensors ranged between 0.04-2.85 μm,and PGD of the intensity-meters' sensors ranged 7.5-26.9 μm.The lower limit of the monitoring capability of the Yunnan Earthquake Early Warning Network is determined by the seismometer network it contains; its average is M_L1.3.The average value of the minimum magnitude for the Yunnan Earthquake Early Warning Network is M_L2.7,and in 55% of Yunnan area the early warning network can detect the magnitudes smaller than M_L3.0.In 95% of Yunnan area the early warning network can detect the magnitudes smaller than M_L3.4.The average time of the first-report for early warning after the earthquake is 5.2 s.For 55% of Yunnan area,the first-report time is less than 5.1 s.For 95% of Yunnan area,the reporting first-report time is less than 5.8 s.Increasing the station of the Yunnan Earthquake Early Warning System can help reduce the lower limit of the magnitude for early warning,and reduce the post-earthquake first report time.The triggering threshold of the Yunnan Earthquake Early Warning System is M_L3.0,which can meet the monitoring requirement.In this case,the whole warning system's exactitude is 0.7797,its precision is 0.8955,its sensitivity is 0.7595,its specificity is 0.8205,and its F1 score is 0.8219.

引言
1 研究方法
2 数据选择
3 预警最小震级评估
4 预警首报时间评估
5 首报触发阈值评估
6 结论

图1 云南地震预警站网3类地震仪器(a)及选取的10%仪器(b)分布<br/>Fig.1 Distribution of three types of seismic instruments of the Yunnan Earthquake Early Warning Network:100% sensors(a)and 10% sensors(b)

图1 云南地震预警站网3类地震仪器(a)及选取的10%仪器(b)分布
Fig.1 Distribution of three types of seismic instruments of the Yunnan Earthquake Early Warning Network:100% sensors(a)and 10% sensors(b)

图2 2023年3类地震仪器PGD热图<br/>Fig.2 Heatmaps of the PGD recorded by the three types of seismic instruments in 2023

图2 2023年3类地震仪器PGD热图
Fig.2 Heatmaps of the PGD recorded by the three types of seismic instruments in 2023

图3 测震仪(a)、强震仪(b)和烈度仪(c)分别单独组网的预警最小震级概率分布直方图和累计概率分布图<br/>Fig.3 Histograms and cumulative probability distribution plots of the minimum earthquake magnitudes for early warning by the seismometer network(a),the strong-motion seismometer network(b)and the intensity meter network(c)

图3 测震仪(a)、强震仪(b)和烈度仪(c)分别单独组网的预警最小震级概率分布直方图和累计概率分布图
Fig.3 Histograms and cumulative probability distribution plots of the minimum earthquake magnitudes for early warning by the seismometer network(a),the strong-motion seismometer network(b)and the intensity meter network(c)

图4 测震仪与强震仪组网(a)、强震仪与烈度仪组网(b)及三网融合组网(c)的预警最小震级概率分布直方图和累计概率分布图<br/>Fig.4 Histograms and cumulative probability distribution plots of the minimum earthquake magnitudes for early warning by the integrated seismometer and strong-motion seismometer network(a),the integrated strong-motion seismometer and intensity meter network(b)and the integration of the three types of network(c)

图4 测震仪与强震仪组网(a)、强震仪与烈度仪组网(b)及三网融合组网(c)的预警最小震级概率分布直方图和累计概率分布图
Fig.4 Histograms and cumulative probability distribution plots of the minimum earthquake magnitudes for early warning by the integrated seismometer and strong-motion seismometer network(a),the integrated strong-motion seismometer and intensity meter network(b)and the integration of the three types of network(c)

表1 云南地震预警站网预警最小震级<br/>Tab.1 Minimum magnitudes observed by the Yunnan Earthquake Warning Network

表1 云南地震预警站网预警最小震级
Tab.1 Minimum magnitudes observed by the Yunnan Earthquake Warning Network

图5 测震仪(a)、强震仪(b)和烈度仪(c)分别单独组网的预警首报时间概率分布直方图和累计概率分布图<br/>Fig.5 Histograms and cumulative probability distribution plots of the first report times for early warnings by the seismometer network(a),the strong-motion seismometer network(b)and the intensity meter network(c)

图5 测震仪(a)、强震仪(b)和烈度仪(c)分别单独组网的预警首报时间概率分布直方图和累计概率分布图
Fig.5 Histograms and cumulative probability distribution plots of the first report times for early warnings by the seismometer network(a),the strong-motion seismometer network(b)and the intensity meter network(c)

表2 云南地震预警站网预警首报时间<br/>Tab.2 Time of the post-earthquake first report by the Yunnan Earthquake Early Warning Network

表2 云南地震预警站网预警首报时间
Tab.2 Time of the post-earthquake first report by the Yunnan Earthquake Early Warning Network

图6 测震仪与强震仪组网(a)、强震仪与烈度仪组网(b)及三网融合组网(c)的预警首报时间概率分布直方图和累计概率分布图<br/>Fig.6 Histograms and cumulative probability distribution plots of the first report times for early warnings by the integrated seismometer and strong-motion seismometer network(a),the integrated strong-motion seismometer and intensity meter network(b)and the integration of the three types of network(c)

图6 测震仪与强震仪组网(a)、强震仪与烈度仪组网(b)及三网融合组网(c)的预警首报时间概率分布直方图和累计概率分布图
Fig.6 Histograms and cumulative probability distribution plots of the first report times for early warnings by the integrated seismometer and strong-motion seismometer network(a),the integrated strong-motion seismometer and intensity meter network(b)and the integration of the three types of network(c)

图7 云南地震预警系统阈值ML3.0时首报触发结果混淆矩阵<br/>Fig.7 The confusion matrix for the first report triggering results at the threshold of ML3.0 of the Yunnan Earthquake Warning System

图7 云南地震预警系统阈值ML3.0时首报触发结果混淆矩阵
Fig.7 The confusion matrix for the first report triggering results at the threshold of ML3.0 of the Yunnan Earthquake Warning System