Sedgwick County has experienced multiple earthquake events in the month of December. As of this posting, there have been a total of 17 events recorded by the KGS Seismic Network, with magnitudes ranging from 2 to 3.9, as shown in the map provided with this caption.

Many of you have asked whether these earthquakes are related to oil and gas activities. The Kansas Corporation Commission completed an investigation to address this, and found that there are no oil and gas activities in the area that suggest this is related to induced seismicity.

You can read their summary here: https://kcc.ks.gov/news-12-23-20 . While the increased number of events is unusual from a human lifespan perspective, it is certainly possible from a geologic time perspective. Sedgwick County has had active earthquake activity since 1919.

The county sits on the western edge of the Nemaha Ridge, which is a buried mountain range that extends from Nebraska to Oklahoma. This ridge was formed approximately 300 million years ago and is bounded by faults, some of which are still slightly active today.

Faults are continuously building up energy over time, and sometimes this energy will be released to bring the faults back to equilibrium. It’s also very common for smaller earthquakes to be felt both before and after a larger event, which is seen here.

E.g. there was a 2.7 event on Dec 28 that preceded the 3.9 event, and the two following events of 2 and 2.6 are aftershocks. We cannot say with certainty that a larger event won’t occur, but based on historical records and the last months activity, it is unlikely in this region.