Lowell, where are you when we need you? The M4 at the Mississippi River in Arkansas border has been followed today by a 2.7 in New Madrid area, and a 3.3 in Illinois. Each following earthquake is about 1 deg latitude (~~100 km) north of the proceeding one. These quakes are all too small and distant to trigger each other by static stress changes (in the opinion of an expert). So, what is going on? Someone might look at a catalogue that give the very small earthquakes in the New Madrid general region, plot them on a map by color for time, or animate them, and see if there is a migration. Or, the Kp index was "red" yesterday and the day before, and briefly this morning. Chris

• USGS NEIS page