Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by MCGARR, A. Search for Related Content GeoRef GeoRef Citation

On a possible connection between three major earthquakes in California and oil production

U. S. GEOLOGICAL SURVEY, 345 MIDDLEFIELD ROAD, MS 977, MENLO PARK, CALIFORNIA 94025

Abstract

The 1983 Coalinga M 6.5, the 1985 Kettleman North Dome M 6.1, and the 1987 Whittier Narrows M 5.9 earthquake sequences each occurred beneath major producing oil fields and caused an aftershock sequence whose epicentral extent coincides approximately with that of the overlying oil field. Despite this coincidence, a causal relationship between these sequences and oil production has been discounted because the earthquakes were located at depths of the order of 10 km, whereas oil production is confined to the topmost several km. Moreover, because all three oil fields, Coalinga, Kettleman, North Dome, and Montebello, are situated on anticlines that have undergone recent uplift as a consequence of horizontal tectonic compression of the crust, natural earthquakes are not unexpected. A mechanical connection between oil production and the earthquake sequence is suggested, however, by the observation that in each case the total seismic deformation was just that required to offset the force imbalance caused by oil production. Specifically, for each of the three sequences M₀ = 2 µm/_c, where M₀ is the sum of the seismic moments, µ is the modulus of rigidity, m is the mass of the fluid removed due to oil production, is the fraction of the upper crust that is seismogenic, and _c is the average upper crustal density. In essence, net extraction of oil and water reduces slightly the average density of the upper crust, causing an isostatic imbalance. The ductile lower crust deforms in response to this imbalance, thus increasing the load on the seismogenic layer, which fails seismically to thicken the crust so as to restore static equilibrium locally. Accordingly, earthquakes near the base of the upper crust may be an expected outcome of major oil production from growing anticlines, irrespective of the depths of the producing formations.

This article has been cited by other articles:

				N. A. Abrahamson, E. Glowacka, and F. A. Nava Major earthquakes in Mexicali Valley, Mexico, and fluid extraction at Cerro Prieto Geothermal Field Bulletin of the Seismological Society of America, February 1, 1996; 86(1A): 93 - 105. [Abstract] [PDF]

				S. D. Davis, P. A. Nyffenegger, and C. Frohlich The 9 April 1993 earthquake in south-central Texas: Was it induced by fluid withdrawal? Bulletin of the Seismological Society of America, December 1, 1995; 85(6): 1888 - 1895. [Abstract] [PDF]