Data sources:
Central U.S. - Cooperative Central and Southeast U.S. Seismic Network CERI/SLU/USC = Center for Earthquake Research and Information
Southeast U.S. - Southeast U.S. Seismic Network = Southeastern U.S. Seismic Networks
Northern California - USGS = U.S. Geological Survey, Menlo Park
Northern California - UCB = University of California, Berkeley
Southern California - USGS = U.S. Geological Survey, Pasadena
Southern California - Caltech = California Institute of Technology
Southern California - UCSD = University of California, San Diego
Nevada - UNR = University of Nevada, Reno
US and World - USGS/NEIC = National Earthquake Information Center