Just before 4am Monday a small earthquake happened in southeastern Missouri.
Earthquakes happen almost every day around the world, but the majority of them go unnoticed.
In the last week there were 15 in southeast Missouri, northwestern Tennessee and northeastern Arkansas.
USGS Earthquake Analyst Don Blakeman says there’s usually around one million earthquakes every year.
“The Earth is really a lot, lot busier than we all think, a lot more active.”
Blakeman says it pretty common for multiple small earthquakes to occur in a short time.
“Sometimes you get a single quake somewhere, you know, just 1.5 or 2.5 somewhere in the in the U.S. and sometimes we get a little swarm, which is how I would describe this, where there's not really a main shock with aftershocks, just a series of little quakes.”
Most earthquakes last a second or two and are over before people realized it was an earthquake.