About the new Madrid Catalog Search

This is a catalog of instrumental locations for earthquakes in the New Madrid Seismic Zone and surrounding regions, 1974 to present. Because the network has evolved over the years, there is no guarantee of consistency in detection threshold, magnitude determination or region covered. The data in this catalog come from numerous sources:

  • 1974-1992: TEIC earthquake bulletin and St Louis Regional Catalog
  • 1993-1994: Saint Louis University and Central Mississippi Valley Earthquake Bulletins
  • 1995-present: earthquakes reported by SLU and/or CERI
  • 2003-present: addition of CERI East TN earthquakes and contributions from the SEUSSN bulletins

Output from the catalog search should have the following columns:

NET: contributing network
DATE: year/month/day
Time: Hour:Minute:Seconds UTC
LAT: Latitude
LON: Longitude
DEP: Depth (km)
MAG: Magnitude
NPH: Number of phases used
GAP: Azimuthal gap in station coverage
DMIN: distance to nearest station (km)
RMS: average rms error of arrivals (sec)
SEO: standard error of origin time
SEH: standard horizontal error (km)
SEZ: standard vertical error (km)
Q: Solution Quality
Magtype: the magnitude type (e.g. w is Moment Magnitude, d is duration Magnitude, lg is Nuttli's mblg magnitude)
Evid: event id
COMMENTS:   Additional comments, including felt information or
independent magnitude determinations.  Events from
1995 on include event quality (A=good, D=poor) and
only report origin times to the nearest second even
though accuracy may be known to a few tens of milliseconds.
Epicentral accuracy varies throughout the catalog but
in no case is better than a few tenths of a kilometer
(0.01 degrees latitude is about 1.11 km or 0.69 miles).

Magnitudes are Md unless otherwise indicated in the comment field.  When available Mb is preferred over Md.
When available, Mw is preferred over Md or Mb.

Note that information does not exist for all field for all events.  If
information is unavailable, then 0 is used.  In some cases depth is fixed
and hence sez is 0.