Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Earthquake swarms and local crustal spreading along major strike-slip faults in California


Earthquake swarms in California are often localized to areas within dextral offsets in the linear trend in active fault strands, suggesting a relation between earthquake swarms and local crustal spreading. Local crustal spereading is required by the geometry of dextral offsets when, as in the San Andreas system, faults have dominantly strike-slip motion with right-lateral displacement. Three clear examples of this relation occur in the Imperial Valley, Coso Hot Springs, and the Danville region, all in California. The first two of these areas are known for their Holocene volcanism and geothermal potential, which is consistent with crustal spreading and magmatic intrusion. The third example, however, shows no evidence for volcanism or geothermal activity at the surface.

This is a preview of subscription content, log in to check access.


  1. Bufe, C. G., Pfluke, J. H., Lester, F. W. andMarks, S. M. (1976),Map showing preliminary hypocenters of earthquakes in the Healdsburg (1:100,000) Quadrangle, Lake Berryessa to Clear Lake, California, January 1969–June 1976. U.S. Geol. Survey Open-File Rept.76-802.

  2. Carver, G. A. (1970),Quaternary tectonism and surface faulting in the Owens Lake Basin, California, MS. Thesis, University of Nevada, Reno.

  3. Combs, J. andRotstein, Y. (1976),Microearthquake studies at the Coso geothermal area, in Proceedings of the Second United Nations' Symposium on the Development and Use of Geothermal Resources2, 909–916.

  4. Donath, F. A. (1962),Analysis of basin-range structure, south-central Oregon, Geol. Soc. Am. Bull,73, 1–16.

  5. Duffield, W. A. andBacon, C. R. (1977),Preliminary Geologic map of the Coso volcanic field and adjacent areas, Inyo county, California, U.S. Geol. Survey Open-File Map77-311.

  6. Elders, W. A., Rex, R. W., Meidov, T., Robinson, P. T. andBiehle, S. (1972),Crustal spreading in southern California, Science,178, 15–24.

  7. Hill, D. P., Mowinckel, P. andPeake, L. G. (1975),Earthquakes, active faults, and geothermal areas in the Imperial Valley, California. Science,188, 1306–1308.

  8. Hill, D. P. (1977),A model for earthquake swarms, J. Geophys. Res.,82, 1347–1352.

  9. Johnson, C. (1977),Swarm tectonics of the Imperial and Brawley faults of southern California (abs), Trans. Am. Geophys. Union,58, 1188.

  10. Johnson, C. E. andHadley, D. M. (1976),Tectonic implications of the Brawley earthquake swarm, Imperial Valley, California, January 1975, Bull. Seism. Soc. Am.,66, 1133–1144.

  11. Klein, F. W. (1976),Earthquake swarms and the semidiurnal solid earth tide, Geophys. R. J. Astr. Soc.,45, 245–295.

  12. Lachenbruch, A. H. (1976),Dynamics of a passive spreading center, J. Geophys. Res.,81, 1883–1902.

  13. Lachenbruch, A. H. andSass, J. H. (1978),Models of an extending lithosphere and heat flow in the basin and range province, Geol. Soc. Am. Special Volume (in press).

  14. Lee, W. H. K., Eaton, M. S. andBrabb, E. E. (1971),The earthquake sequence near Danville, California, 1970, Bull. Seism. Soc. Am.,61, 1771–1794.

  15. Lee, W. H. K. andVedder, J. G. (1973),Recent earthquake activity in the Santa Barbara Channel region, Bull. Seism. Soc. Am.,63, 1757–1773.

  16. Lomnitz, C., Mooser, F., Allen, C. andThatcher, W. (1970),Seismicity and tectonics of the Northern Gulf of California region, Mexico, preliminary results, Geofis. Int.,10, 37–48.

  17. Nakamura, K. (1977),Volcanoes as possible indicators of tectonic stress orientation-principal and proposal, Jour. Volcanology and Geothermal Res.,2, 1–16.

  18. Oldenburg, D. W. andBrune, J. N. (1975),An explanation for the orthogonality of ocean ridges and transform faults, J. Geophys. Res.,80, 2575–1585.

  19. Savage, J. C., Church, J. P. andPrescott, W. H. (1975),Geodetic measurement of deformation in Owens Valley, California, Bull. Seism. Soc. Am.,65, 865–874.

  20. Sharp, R. V. (1976),Surface rupturing in Imperial Valley during the earthquake swarm of January–February, 1975, Bull. Seism. Soc. Am.,66, 1145–1154.

  21. Sykes, L. R. (1967),Mechanism of earthquakes and nature of faulting on the mid-ocean ridges, J. Geophys. Res.,72, 2131–2153.

  22. Sylvester, A. G., Smith, S. W. andSchulz, C. H. (1970),Earthquake swarm in the Santa Barbara Channel, California, 1968, Bull. Seism. Soc. Am.,60, 1047–1060.

  23. Ward, P. L. (1972),Microearthquakes: prospecting tool and possible hazard in the development of geothermal resources, Geothermics,1, 3–12.

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Weaver, C.S., Hill, D.P. Earthquake swarms and local crustal spreading along major strike-slip faults in California. PAGEOPH 117, 51–64 (1978). https://doi.org/10.1007/BF00879733

Download citation

Key words

  • Strike-slip faults
  • Crustal spreading centers
  • Fault plane solutions
  • Stress directions
  • Brawley and Coso Hot Springs geothermal areas (USA)