The Korean ancient literature, Joseonwangjosillog, describes the historical earthquake swarm in the Sangwon area from 1565 to 1566 during the seismically active period (1500–1750) in Korea. More than one hundred earthquakes with magnitudes of 3.0– 4.6 occurred collectively in the same place for five consecutive months. Another description in this literature states this phenomenon lasted for eight months to almost one year. There is no evidence related to volcanic or hydrothermal activities around the Pyongyang– Sangwon areas in historical times. One possible explanation for the high seismicity and swarm activity in these areas may be associated with the reactivation of some faults and fault intersections in a highly fractured zone that act as stress concentrators, respectively. No other swarms like this were recognized in the historic records over the past nineteen hundred years.

韩国古代文献Joseonwangjosillog描述了1565年至1566年韩国地震活跃时期（1500-1750年）上原地区的历史地震群。连续五个月在同一地点集体发生了100多次3.0-4.6级地震。该文献中的另一种描述指出，这种现象持续了八个月到将近一年。在历史时期，没有证据表明平壤至上原地区周围的火山或热液活动。对于这些地区的高地震活动和群活动的一种可能的解释可能与分别充当应力集中器的高度断裂带中的某些断层和断层相交的重新激活有关。