1998 OCT30 Grant County, Oklahoma Earthquake

Origin time 17:41:22.30 UTC/GMT, Latitude 36.779degrees N, Longitude 97.576degrees W

Magnitude(s): mbLg 3.5

BROAD BAND VERTICAL, RADIAL, AND TRANSVERSE SEISMOGRAMS OF THE 1998 OCT30 OKLAHOMA EARTHQUAKEjl

This felt earthquake had an epicenter about 25 miles NW of Ponca City.
It was felt widely in Grant, Garfield, and KAY Counties. No damage or
injuries are expected.

The above seismogram is earth acceleration recorded from three Geotech BB-13
seismometers in the walk-in vault at Leonard. The signals were digitized 40
times per second. 

P waves and S waves from the earthquake are labelled.

The seismogram labelled "bz" is vertical earth acceleration. The seismogram
marked "br" is horizontal earth acceleration in a line to the epicenter and
away from the epicenter (r=radial). "bt" is horizontal earth acceleration
at right angles (t=transverse) to the direction of the epicenter. The 
horizontal seismometers are lined North-South, and East-West, but simple
trigonometry in the "Geotool" seismic analysis package combines and rotates
the horizontal traces.

To help OGS map the felt effects of this earthquake, would anyone who
felt and/or heard the earthquake at 11:41AM OCT30 please write to us?

Please tell us where you were, and what you experienced in as much detail
as possible. Mail to:

Oklahoma Geological Survey
Box 8
Leonard, OK 74043

or to:

Earthquake
Leonard, OK 74043

or E-mail to:

jimlawson@okgeosurvey1.gov (You can't mail directly from this web page).

EARTHQUAKE CATALOG INDEX HOME SEISMOGRAM INDEX