Possible triggering of earthquakes by underground waste disposal in the El Dorado, Arkansas area


From December, 1983 to September, 1989 twelve small earthquakes were recorded for the El Dorado, Arkansas area. Although the hypocenters for these events are poorly defined, observations presented here support the conclusion that the quakes were triggered. El Dorado is located at the margin of a region of underground waste brine disposal and along a major fault zone. Elevated pore pressures resulting from brine disposal may have reduced the normal stresses across fault surfaces and triggered fault movement. The two injection wells in the El Dorado South field in closest proximity to fault surfaces at the depth of injection also lie at the center of macroseismic area of a magnitude 2.5 earthquake of December 12, 1988 and show increases in injection rates prior to periods of seismicity. -from Author

Publication Title

Seismological Research Letters