2020年7月12日，河北唐山发生M_S5.1地震，河北省地震预警系统成功地处理并产出了这次地震预警各种结果数据，本文借助此次地震对河北地震预警网内震中距200km范围内台站产出质量以及地震预警前5次处理结果进行详细分析。此次地震发生在河北地震预警网内，平均台间距为10km，首台触发后3s、震后6s发布首次处理结果，与编目结果相比，震级偏差为-1.3，震中位置偏差为2.6km，盲区半径为18km。随着参与定位台站数量增多，震级与位置偏差越来越小，但震级仍整体偏小。河北地震预警网台站产出质量整体较高，其中烈度台作为地震预警最重要的组成部分，是决定预警效果的关键因素。本次地震震中距200km范围内，烈度台平均信噪比为48，震中距50km范围内平均信噪比为112，符合预警系统对信噪比的要求。本次地震预警结果表明，河北地震预警网内台站布局基本合理，波形质量较高，地震预警系统处理软件在本次地震中预警产出效果较好，已经具备了一定的地震预警能力。

On July 12,2020,an M_S5.1 earthquake occurred in Tangshan,Hebei Province. The earthquake early warning system of Hebei Province has successfully processed and output all kinds of related data for earthquake early warning. In this paper we analyzed the output data quality of stations within 200km away from the epicenter in the Hebei early warning network,as well as the first 5 processing results of the JEEW earthquake early warning system of the Research Institute of Shenzhen. The earthquake occurred within the Hebei early warning network with an average distance of 10km between stations. Compared to formal reports of China Earthquake Networks Center,the first alarm of JEEW was generated in 3s after the first station triggered,in 6s after the earthquake,with a location error of 2.6km,and magnitude error of -1.3,and blind spot radius of 18km. With the increase of participation number positioning stations,the magnitude and location error are getting smaller and smaller,but the absolute value of magnitude is still small. For Hebei early warning network,the average signal-to-noise ratio of the intensity stations within 200km of epicenter is 48,and the average signal-to-noise ratio of the intensity stations within 50km of epicenter is 112,which fully meets the requirement of early warning system of signal to noise ratio. The earthquake early warning results of the Tangshan M_S5.1 earthquake show that the layout of the stations within the network is basically reasonable,the waveform quality is high,and the JEEW earthquake early warning system of Shenzhen Research Institute has a good early warning effect in this earthquake. Overall,Hebei early warning network has been of a certain earthquake early warning ability.

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河北省地震局测震专业仪器系统检测评估与观测场地遴选创新团队、河北省省科技厅项目“紧急地震信息服务系统在政府和教育部门的研究和应用”（17275407D）共同资助