Monday, November 7, 2011
Earthquakes in Oklahoma
Oklahoma experienced a magnitude 4.7 earthquake early Saturday, and then a magnitude 5.6 quake (the strongest on record for the state) just before 11 p.m. Since Saturday night the state has felt 10 aftershocks. This is the latest episode in a steady rise in seismic activity that led the USGS to install new monitors in the state last year. Nobody knows why.