Earthquake-earthquake interaction

Article By:

Harris, Ruth A. U.S. Geological Survey, Menlo Park, California.

Last reviewed:2001

DOI:https://doi.org/10.1036/1097-8542.YB011510

Since the early 1900s there have been documented cases of humans influencing the occurrence of earthquakes by gold and coal mining, fluid injection and withdrawal, and reservoir impoundment. Famous examples include the magnitude-5 earthquakes in the Denver, CO, area in the 1960s, which were caused by the injection of hazardous waste; and two earthquakes associated with reservoir loading, the magnitude-6.5 earthquake in Koyna, India, in 1967 and the magnitude-5.3 earthquake at Aswan Dam on the Nile River in Egypt in 1981. The Koyna earthquake killed 200 people. Near Reading, PA, a magnitude-4.6 earthquake in 1994 caused more than $2 million in damage; this earthquake, in a setting where tectonic activity rarely produces earthquakes, was caused by quarry unloading. Human-induced earthquakes are best detected in regions where the Earth's strain rates are quite low and therefore the earthquakes stand out in contrast to the very low expected number of events. Scientists develop mathematical models of stresses in the earth generated by human activity and correlate the stresses with the location and time of the subsequent earthquakes.

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