2021年5月21日21时48分（北京时间）云南大理州漾濞县发生M_S6.4地震。中国地震台网中心在震后8min发布正式速报结果，随后联合多家单位启动地震相关产品的应急产出工作，共产出地震基本参数、历史地震、地震构造、震源机制、仪器地震烈度和余震精定位等9类14种数据产品。产品结果显示，本次地震发生在川滇地块滇西地区，位于维西-乔后-巍山断裂地震带附近，震源机制解表明该地震为一次走滑型事件，断层呈SE走向，余震主要沿主震SE方向拓展约20km，深度主要集中在10km及以浅范围。该地震极震区推测烈度达到Ⅷ度，区域涉及太平乡、富恒乡、漾江镇和苍山西镇4个乡镇，面积约227km²。距震中9km处的强震台站记录到的三分量峰值加速度值均大于该地区的设防标准，表示该地震可能造成震中附近漾濞县的人员伤亡以及房屋破损，与灾情调查结果吻合。

The M_S6.4 earthquake occurred at 21:48 PM on May 21,2021,in Yangbi County,Dali Prefecture,Yunnan Province. China Earthquake Networks Center reported the formal quick report in 8min. After the earthquake,together with some units of China Earthquake Administration,China Earthquake Network Center immediately started work on the emergency output of earthquake-related products,producing a total of 9 categories and 14 data products including basic seismic parameters,historical earthquakes,seismological tectonics,source mechanism,instrumental seismic intensity and aftershocks precision positioning,and so on. These products implies that this earthquake occurred at the western part of the Yunnan,Chuandian block,located near the Weixi-Qiaohou-Weishan faults. Focal mechanism result suggests a strike-slip event,the fault heading north-west to south-to-east. The aftershock mainly expands about 20km along the southeast direction of the main earthquake. The depth mainly concentrates in 10km and in a shallow range. The predicted intensity of the epicenter area reaches eight degree. The area involves Taiping Township,Fuheng Township,Yangjiang Town and Cangshan West Town,with an area of about 227 square kilometers. The three-component peak acceleration values recorded at 9km from the epicenter are greater than the fortification standard in the area. It implies that the earthquake could cause casualties and house damage in Yangbi County near the epicenter,which was consistent with the disaster investigation on site.

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“全球地震速报数据接入”项目（12150411013）资助