Two aftershocks occurred on Friday, stemming from the Wednesday morning 4.3 earthquake that hit Saline County, just southwest of Gypsum.
The aftershocks were measured 2.2 and 2.3 on the Richter Scale, rumbling at 12:12 pm and 9:56 pm, respectively.
By definition, an aftershock occurs after a sizeable quake, usually a 4.0 or stronger. Although there's no cut-off point for aftershocks to stop, the larger an earthquake is, the longer aftershocks will last.
Aftershocks occur in the same vicinity as the earthquake from which they derived. The 22 aftershocks that have happened since Wednesday have been in a 3 mile radius of the initial seismic activity.
Finally, aftershocks eventually calm down. 15 were recorded by Kansas Geological Survey in the first 24 hours after the 4.3 quake. In day 2 after, only 5 aftershocks were recorded.
