How do I know that it was an earthquake I felt rather than a sonic boom or some other cause?
Most small earthquakes in Ohio (2 or 3 magnitude) are felt throughout a part of a county or several counties, and most strongly near the epicenter. Many people describe a booming sound followed by a sharp jolt and a few seconds of shaking. Some describe the sound as decreasing to a low rumble as it quickly passes into the distance. Commonly, the booming sound is at first interpreted as a sonic boom from an aircraft or an explosion ("I thought the furnace had exploded"). Although military aircraft do occasionally and inadvertently break the sound barrier, this is uncommon. The booming sound many people report is thought to be from P waves (the fastest moving seismic waves) exiting the ground and in audible frequencies. Some of the noise is probably related to the shaking of the building and to the brittle bedrock as the seismic wave pass through. Many people in favorable positions (sitting or resting) feel vibrations that they interpret as possible earthquakes. In most cases these felt events are not attributable to earthquakes. It is probable that they are local atmospheric or cultural in origin.