And that's part of the reason why many are alarmed over earthquake swarms.

这就是许多人对震群感到恐慌的部分原因。

An earthquake swarm is a concentration of earthquakes in a short period of time.

震群是在很短时间内集中的地震。

Thousands in recent months. Now, they are relatively small and they are in a relatively remote part of the state. But seismologists are concerned over these earthquake swarms.

最近几个月已达几千次。现在, 这些地震已相对较小, 并且这个州处于相对偏远的地区。但地震学家对这些震群感到担心。