The U.S. Geological Survey at the University of Memphis said the quakes occurred within a mile of the same location, 22 miles south of Sikeston near Lilbourn, Missouri.
The first happened at 11:18 am, and a second tremor quickly followed at 11:29. The third quake happened at 11:57 am. Three hours later, the fourth quake was measured at 3:31 pm.
The tremors were measured at preliminary magnitudes of 2.8, 2.8, 2.7 and 2.5 respectively.
Later, the USGS added that an earlier smaller tremor of 1.8 occurred in the same area at 11:34 am.
The USGS says that a magnitude of 2.5 is the threshold of humans being able to detect the ground shaking.
No damage has been reported from the earthquakes.
NOTE: Since publication on Monday afternoon, three more tremors were recorded in southeast Missouri Monday night and Tuesday morning. All were in the 1.6 magnitude range. Over the past week, about 15 tremors have occurred in that area.
