It’s no secret that the ground beneath our feet has been shaking a bit more in recent years.
Yesterday NewsOK reported that Oklahoma had 222 earthquakes in 2013 that registered as 2.5-magnitude or greater—more than any other year in state history. As of Feb. 17, there were 63 earthquakes that were 2.5-magnitude or greater already in 2014.
Here’s a timelapse of all the 2.5-magnitude or greater earthquakes to shake Oklahoma since 2004. The radius of the circle indicates a greater magnitude.
Pause the animation and drag the slider to take a closer look at each year.
Source: Oklahoma Geological Survey
Three earthquakes shook Logan County Sunday night, ranging from 2.9-magnitude to 3.8-magnitude. Again this morning, another 3.8-magnitude quake shook Guthrie.
Data from the USGS shows that one to three 3.0-magnitude earthquakes or larger occurred annually from 1975 to 2008. But that number grew to around 40 earthquakes per year from 2009 to 2013.
The reason for the increase in earthquakes is still up for debate. Last year USGS seismologist Bill Leith suggested that the rise in quakes may not entirely be natural.
“We’ve statistically analyzed the recent earthquake rate changes and found that they do not seem to be due to typical, random fluctuations in natural seismicity rates,” he said.