Seismotectonic maps in the vicinity of the lower Wabash Valley, Illinois, Indiana, and Kentucky - Digital Spatial Database: Instrumental earthquake locations

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Description This cover contains the catalog of earthquake locations, within the project boundary, recorded by the Saint Louis University and Memphis State University seismic networks from July 1974 through December 1995.
Originators Rhea, Susan
Publication U.S. Geological Survey Open-File Report 97-0681

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earthquake location data

Label Definition
DATE YYMMDD of earthquake, Universal Time Coordinated
TYPE refers to central US velocity model used to locate earthquake
HR origin time hour, Greenwich Universal Time Coordinated
MIN origin time minute
SEC origin time seconds with partial seconds
LAT location, latitude north
LONG location, longitude W
DEPTH location, depth in kilometers
DEPTAG tag for free or fixed depth in location routine
MAG magnitude, computed from averaged displacement magnitudes at each station
NSTA number of stations used to determine earthquake location
NPHASE number of p- and s- phases used to determine earthquake location
GAP largest aperture between stations recording earthquake, in degrees
DMIN epicentral distance to closest station, in km
RMS Root Mean Square of travel-time residuals after location algorithm iterations
ERH standard error of horizontal location in km
ERZ standard error of depth in km
QH quality of horizontal location, based on evaluation of ERH, RMS, NSTA, and NPHAS
QZ quality of depth location, based on evaluation of ERZ, RMS, NSTA, and NPHASE
MOD code for velocity model used to compute earthquake location
DFLAG (no definition)
MBLG3 magnitude determined from Lg surface waves