At least twenty earthquakes have occurred in the Texas Panhandle north of 34°N since 1907. The largest earthquakes had magnitudes up to 4.8, and the intensities throughout the Panhandle have ranged from IV to VI (Modified Mercalli), corresponding to accelerations from 6.8 cm/s² to over 31.6 cm/s².
The record of seismicity in the Texas Panhandle dates back to 1907 when the first reported event occurred near Amarillo. Since then, numerous events have been reported or instrumentally recorded from the Panhandle. In the most complete survey of seismicity in the Panhandle (north of 34° latitude) to be undertaken, 20 earthquakes were identified from 1907 through July 1982. Slightly more than half of the events have locations determined from felt reports, and the others from instrumental locations.
During the process of identifying earthquakes, contemporary newspaper accounts, weather bulletins, seismological reports, and other sources were reviewed. Several reported events were found to be in error. Specifically, the published locations of some events are erroneous by tens or hundreds of kilometers, one event was, in fact, a sonic boom, and one "event" near the Panhandle resulted from spurious data reported from seismological observatories nearby.
The largest earthquakes in the Texas Panhandle had magnitudes of 4.7 to 4.8 (determined by maximum intensity and felt areas); there were five such events between 1917 and 1951. Since instrumental recording became widespread in about 1962, only two events of magnitude greater than 4.0 have occurred. Although some of the earthquakes reported have been assigned magnitudes of 3.0 or less, the detection threshold is probably considerably higher. As evidence, it is noted that a magnitude 3.4 event in 1983 would have been undetected by conventional procedures, had there not been a specific interest in modern seismicity. Since this interest did not exist until recently, it is probable that many earthquakes of magnitude up to 3.5 have gone unrecognized, and it is likely that some larger events have been missed as well.Bureau of Economic Geolog
