An earthquake was felt around 4:30 this morning in the Chicago region. And the people who felt it most acutely were the residents of West Salem in southern Illinois. Among them was Eric Goldsmith, West Salem’s mayor. We spoke with him earlier this morning. We haven’t had an earthquake of this size in forty years so to find out why it happened and whether we can expect more, we’ve turned to the U. S. Geological Survey, in Denver Colorado.

Music Button: Uncle Tupelo, “New Madrid,” from the CD Anodyne, (Sire records).