Five aftershocks have been reported in the last 24 hours since Wednesday's 4.3 quake in Saline County. That is down significantly from the 15 reported in the first 24 hours.
While there is no magic cut-off when aftershocks stop after a sizeable quake, the frequency of the seismic events do lessen as time goes on.
Think of an aftershock as the earth's way of letting off steam after the initial quake. Calming down, if you will.
According to Kansas Geological Survey, the largest aftershock in the last day was a 2.7 that occurred at 7:59 yesterday evening.
By definition, an aftershock meets the following criteria:
• Occurs after a sizeable quake, usually that of 4.0 or stronger.
• Lessens in frequency as time passes. The larger the initial quake, the longer aftershocks will last.
• Occur in a cluster of the epicenter of the initial quake. An epicenter is the bullseye of the quake, or where the rumbling began. It is from this point that the quake ripples out.
• Is less in magnitude than the initial quake. For instance, the earthquake on Wednesday was a 4.3. The aftershocks to follow should be less than 4.3, as measured by the Richter Scale.