Since just after midnight, seismographs at the U.S. Geological Survey office in Memphis have recorded nine separate minor quakes, all centered about 22 miles south of Sikeston, MO.
All occurred between 12:50 am and 2:26 am.
The first three quakes were the strongest, as they rattled in quick succession within 18 minutes, with magnitudes of 2.9, 2.3 and 3.0. Others in the sequence ranged from 2.6 down to 1.6 magnitude.
Quakes of magnitudes less than 2.5 generally go unnoticed by the public.
On the Net:
University of Memphis - Quake map