CATALOGS - A catalog consists of summary lines, usually one line per earthquake, giving earthquake time, location, and magnitude.
Catalog Completeness varies geographically, and over time. Better instrumentation improves catalog completeness.
Search pages allow you to set search parameters and get a list of earthquakes that meet your criteria.

TRACE DATA AND STRONG MOTION - Trace data consists of digital samples from seismometers. Sample rates are usually 50-100 samples/sec, and the files are large. Trace data can be plotted and /or analyzed by engineers, seismologists, and seismologists-in-training.

Strong-motion parameters are calculated from the trace data of special instruments that record strong shaking in larger earthquakes.

STATIONS - PNSN Stations

FOCAL MECHANISMS (also called "Beach Balls") - A focal mechanism helps determine the angle and orientation of the fault. USGS Page on Focal Mechanisms

INTENSITIES - Shaking intensity can be measured instrumentally, or determined from reports of earthquake effects. Shaking intensity varies from place to place, depending on earthquake size and distance, and geologic and topographic conditions.
Shaking Intensity from C. J. Ammon, St. Louis. U.

HISTORIC EARTHQUAKES - Information is available for notable past earthquakes.

QUARTERLY REPORTS - 1995 to present. Seismicity reports by calendar quarter

ANNUAL REPORTS - 1995 to present. Summaries of Technical Reports for National Earthquake Hazards Reduction Program