After the 6.5 magnitude earthquake that his Nevada last week on May 15, hundreds of aftershocks have followed. A dozen aftershocks of 4.5 aftershocks of 4.5 and above and 500 quakes of 2.5 and above have been recorded near Tonopah since the 6.5 quake.

For more info, please read the original article by SF Gate:
https://www.sfgate.com/earthquakes/article/Nevada-Tonopah-earthquakes-6-5-aftershocks-15283968.php