Creep response of the Hayward fault to stress changes caused by the Loma Prieta earthquake

Science

Volumn 276, Issue 5321, 1997, Pages 2014-2016

  Lienkaemper, James J ^a   Galehouse, Jon S ^a   Simpson, Robert W ^a  

^a NONE

Author keywords

[No Author keywords available]

Indexed keywords

CREEP; FAULT SLIP; LOMA PRIETA EARTHQUAKE 1989; STRESS;

ARTICLE; EARTHQUAKE; GEOLOGY; PRIORITY JOURNAL; STRESS; UNITED STATES;

USA, CALIFORNIA;

EID: 0030808991     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.276.5321.2014     Document Type: Article

References (16)

1. R. W. Simpson, S. S. Schulz, L. D. Dietz, R. O. Burford, Pure Appl. Geophys. 126, 665 (1988).
2. Working Group on California Earthquake Probabilities, U.S. Geol. Surv. Circ. 1053, 51 (1990).
3. J. J. Lienkaemper, G. Borchardt, M. Lisowski [J. Geophys. Res. 96, 18261 (1991)], being revised as J. J. Lienkaemper and J. S. Gatehouse, in preparation; J. J. Lienkaemper, J. S. Gatehouse, R. W. Simpson, Eos 73, 119 (1992); _, K. S. Breckenridge, ibid. 74, 192 (1993).
4. J. J. Lienkaemper, G. Borchardt, M. Lisowski [J. Geophys. Res. 96, 18261 (1991)], being revised as J. J. Lienkaemper and J. S. Gatehouse, in preparation; J. J. Lienkaemper, J. S. Gatehouse, R. W. Simpson, Eos 73, 119 (1992); _, K. S. Breckenridge, ibid. 74, 192 (1993).
5. J. J. Lienkaemper, G. Borchardt, M. Lisowski [J. Geophys. Res. 96, 18261 (1991)], being revised as J. J. Lienkaemper and J. S. Gatehouse, in preparation; J. J. Lienkaemper, J. S. Gatehouse, R. W. Simpson, Eos 73, 119 (1992); _, K. S. Breckenridge, ibid. 74, 192 (1993).
6. P.A. Reasenberg and R. W. Simpson, Science 255, 1687 (1992).
7. R. W. Simpson and P. A. Reasenberg, U.S. Geol. Surv. Prof. Pap. 1550-F, 55 (1994).
8. J. S. Gatehouse, Geophys. Res. Lett. 17, 1219 (1990); U.S. Geol. Surv. Prof. Pap., in press.
9. J. S. Gatehouse, Geophys. Res. Lett. 17, 1219 (1990); U.S. Geol. Surv. Prof. Pap., in press.
10. _, B. D. Brown, B. Pierce, J. J. Thordsen, Calif. Div. Mines Geol. Spec. Publ. 62, 239 (1982).
11. J. Langbein and H. Johnson, J. Geophys. Res. 102, 591 (1997).
12. J. C. Savage and M. Lisowski, ibid. 98, 787 (1993).
13. The previous largest event on the fault was 10 mm in 1983 during a 124-day interval at km 62. The date of the 18-mm event may be 9 February 1996, when a water main broke at km 65.9 on the fault. This 1996 event extended more than 1.7 km (from km 65.3 to 67.0), as shown on four arrays but less than 3.7 km, as limited by other data. We observed no triggered slip on the Hayward fault in 1989 except for 3 mm that showed on fresh cracks at km 66.3 (3).
14. Suddenness of resumption of fast creep from km 65 to 67 may be caused by two extremely rainy seasons following a drought. North of km 63, all sites had resumed pre-Loma Prieta rates by 1994. Two sites, km 63 and 64, resumed nearly normal rates during 1994. A creepmeter at km 63.6 resumed a 9 mm/year rate by late 1995 with no large event in early 1996. We note that a borehole strain-meter located 5 km northeast of the ∼18-mm creep event recorded a strain event starting on 7 February 1996. These data are consistent with slip of 18 mm on a patch ∼1 km in extent (M. Johnston, personal communication). Possibly, creep began steadily at depth months earlier, not slipping at the surface until induced by a water table raised by heavy rains.
15. M. Lisowski, W. H. Prescott, J. C. Savage, M. J. Johnston, Geophys. Res. Lett. 17, 1437 (1990). Dislocation model parameters: 37 km in length; 316° strike, 70°SW dip; depth of 5 to 17.5 km; 1.66-m dextral slip; and 1.19-m reverse. Other models tested yield similar results for the Hayward fault (4, 5).
16. Funded by the U.S. Geological Survey National Earthquake Hazards Reduction Program (NEHRP) and San Francisco State University (NEHRP contract 1434-94-G2420). We thank many student assistants, especially C. Garrison, O. Graves, T. Hoyt, and F. McFarland; the governments of Fremont, Hayward, San Leandro, and Oakland; W. Hazelwood of the Bay Area Rapid Transit District; D. J. Russell; and two anonymous reviewers, W. Prescott and J. Langbein.