Abstract—One of the strongest deep earthquakes that occurred on August 18, 2018, M_W = 8.2, h = 600 km off the Tonga Islands is analyzed. This earthquake is notable for having a powerful aftershock sequence which is generally untypical of the deep earthquakes and which justifies considering this quake as a unique seismic event. Based on the first-day aftershocks, a three-dimensional (3D) geometric model of the source is constructed, and the seismic history and peculiarities of the aftershock process are studied. In particular, the duration of the aftershock process and the amount of the scalar seismic moment released by the aftershocks are estimated. It is shown that the source of the earthquake of August 18, 2018 pertains to the NDC type. Some characteristics of the earthquake of August 18, 2018 are compared with those of the strong deep ​​earthquake with M_W = 8.3 that occurred in the Sea of Okhotsk on May 24, 2013 off the western coast of Kamchatka.

摘要—2018年8月18日发生的最强烈的深地震之一，M _W = 8.2，h=距离汤加群岛600公里。这次地震以强大的余震序列而著称，这通常是深地震所不具备的，因此有理由将此次地震视为独特的地震事件。基于第一天的余震，构造了震源的三维（3D）几何模型，并研究了地震的历史和余震过程的特殊性。特别是，估计了余震过程的持续时间和余震释放的标量地震矩的数量。结果表明，2018年8月18日的地震震源与NDC类型有关。将2018年8月18日地震的某些特征与M _W强烈强震的特征进行了比较 = 8.3，发生于2013年5月24日在堪察加半岛西海岸的鄂霍次克海。