Is the number of felt earthquakes occurring northeast of Oklahoma City, unusual? Somewhat, but at this point there is no reason to be alarmed. Small earthquakes such as these can occur anywhere in the world. The US Geological Survey (USGS) estimates that there are as many as 3,000 of these small earthquakes occurring every day. Earthquake swarms like this can go on for many months, and usually do not lead up to a major earthquake.
Do we know what is causing the earthquakes? No, without further study it is not possible to determine what is causing the earthquakes. The USGS and the Oklahoma Geological Survey are working together to conduct a limited field study to better measure any future earthquakes that could occur in eastern Oklahoma County.