Response of the San Andreas fault to the 1983 Coalinga-Nuñez earthquakes: An application of interaction-based probabilities for Parkfield

(1) The Parkfield-Cholame section of the San Andreas fault, site of an unfulfilled earthquake forecast in 1985, is the best monitored section of the world's most closely watched fault. In 1983, the M = 6.5 Coalinga and M = 6.0 Nunez events struck 25 km northeast of Parkfield. Seismicity rates climbed for 18 months along the creeping section of the San Andreas north of Parkfield and dropped for 6 years along the locked section to the south. Right-lateral creep also slowed or reversed from Parkfield south. Here we calculate that the Coalinga sequence increased the shear and Coulomb stress on the creeping section, causing the rate of small shocks to rise until the added stress was shed by additional slip. However, the 1983 events decreased the shear and Coulomb stress on the Parkfield segment, causing surface creep and seismicity rates to drop. We use these observations to cast the likelihood of a Parkfield earthquake into an interaction-based probability, which includes both the renewal of stress following the 1966 Parkfield earthquake and the stress transfer from the 1983 Coalinga events. We calculate that the 1983 shocks dropped the 10-year probability of a M � 6 Parkfield earthquake by 22% (from 54 ± 22% to 42 ± 23%) and that the probability did not recover until about 1991, when seismicity and creep resumed. Our analysis may thus explain why the Parkfield earthquake did not strike in the 1980s, but not why it was absent in the 1990s. We calculate a 58 ± 17% probability of a M � 6 Parkfield earthquake during 2001- 2011. INDEX TERMS: 7223 Seismology: Seismic hazard assessment and prediction; 7230 Seismology: Seismicity and seismotectonics; 7260 Seismology: Theory and modeling; KEYWORDS: Coalinga earthquake, Parkfield, stress change, earthquake probability, seismicity rate

[1]  R. E. Habermann.  Teleseismic detection in the Aleutian Island Arc , 1983 .

[2]  P. Reasenberg,et al.  Stress sensitivity of fault seismicity: A comparison between limited‐offset oblique and major strike‐slip faults , 1999 .

[3]  P. Reasenberg,et al.  Response of Regional Seismicity to the Static Stress Change Produced by the Loma Prieta Earthquake , 1992, Science.

[4]  W. Bakun.  Seismic activity of the San Francisco Bay region , 1999, Bulletin of the Seismological Society of America.

[5]  Thomas V. McEvilly,et al.  Recurrence models and Parkfield, California, earthquakes , 1984 .

[6]  J. Dieterich,et al.  Stress transferred by the 1995 Mw = 6.9 Kobe, Japan, shock: Effect on aftershocks and future earthquake probabilities , 1998 .

[7]  M. Wyss,et al.  Minimum Magnitude of Completeness in Earthquake Catalogs: Examples from Alaska, the Western United States, and Japan , 2000 .

[8]  R. Simpson,et al.  The response of creeping parts of the San Andreas fault to earthquakes on nearby faults: Two examples , 1988 .

[9]  S. L. Crouch,et al.  Boundary element methods in solid mechanics , 1983 .

[10]  A. Barka,et al.  Heightened odds of large earthquakes near istanbul: An interaction-based probability calculation , 2000, Science.

[11]  W. Bakun,et al.  Temporal changes in microseismicity and creep near Parkfield, California , 1987, Nature.

[12]  A. Freed,et al.  Time‐dependent changes in failure stress following thrust earthquakes , 1998 .

[13]  F. Waldhauser,et al.  Slip-Parallel Seismic Lineations on the Northern , 1999 .

[14]  L. Jones,et al.  Seismicity alert probabilities at Parkfield, California, revisited , 1998, Bulletin of the Seismological Society of America.

[15]  W. Prescott,et al.  Inversion of GPS data for spatially variable slip‐rate on the San Andreas Fault near Parkfield, CA , 2001 .

[16]  M. Gladwin,et al.  Anomalous shear strain at Parkfield during 1993–94 , 1996 .

[17]  E. Roeloffs.  Creep rate changes at Parkfield, California 1966–1999: Seasonal, precipitation induced, and tectonic , 2001 .

[18]  Max Wyss,et al.  Inadvertent changes in magnitude reported in earthquake catalogs: Their evaluation through b-value estimates , 1995, Bulletin of the Seismological Society of America.

[19]  G. Ekström,et al.  Seismicity and geometry of a 110 km-long blind thrust fault: 1 , 1992 .

[20]  J. Eaton.  The earthquake and its aftershocks from May 2 through September 30, 1983 , 1990 .

[21]  P. Spudich,et al.  Rupture characteristics of the three M ∼ 4.7 (1992–1994) Parkfield earthquakes , 1998 .

[22]  R. E. Habermann,et al.  Seismic quiescence at Parkfield: an independent indication of an imminent earthquake , 1990, Nature.

[23]  J. B. Fletcher,et al.  Stress drop for three M∼4.3–4.7 (1992–1994) Parkfield, CA, earthquakes , 1999 .

[24]  R. Stein.  The role of stress transfer in earthquake occurrence , 1999, Nature.

[25]  Robert M. Nadeau,et al.  Seismological studies at Parkfield VI: Moment release rates and estimates of source parameters for small repeating earthquakes , 1998, Bulletin of the Seismological Society of America.

[26]  S. Wiemer,et al.  Change in the probability for earthquakes in Southern California due to the Landers magnitude 7.3 earthquake. , 2000, Science.

[27]  William L. Ellsworth,et al.  A Brownian Model for Recurrent Earthquakes , 2002 .

[28]  M. Wyss,et al.  Mapping the frequency-magnitude distribution in asperities: An improved technique to calculate recurrence times? , 1997 .

[29]  W. Bakun,et al.  Earthquakes near Parkfield, California: Comparing the 1934 and 1966 Sequences , 1979, Science.

[30]  R. Simpson,et al.  Suppression of large earthquakes by stress shadows: A comparison of Coulomb and rate-and-state failure , 1998 .

[31]  Yijun Du,et al.  How similar were the 1934 and 1966 Parkfield Earthquakes , 1993 .

[32]  F. Waldhauser,et al.  A Double-Difference Earthquake Location Algorithm: Method and Application to the Northern Hayward Fault, California , 2000 .

[33]  John Langbein,et al.  The earthquake prediction experiment at Parkfield, California , 1994 .

[34]  A. Barka,et al.  Slip distribution along the North Anatolian fault associated with the large earthquakes of the period 1939 to 1967 , 1996, Bulletin of the Seismological Society of America.

[35]  Yehuda Ben-Zion,et al.  Interaction of the San Andreas Fault Creeping Segment with Adjacent great rupture zones and earthquake recurrence at Parkfield , 1993 .

[36]  James H. Dieterich,et al.  Progressive failure on the North Anatolian fault since 1939 by earthquake stress triggering , 1997 .

[37]  Effects of the 1983 Coalinga, California, earthquake on creep along the San Andreas fault , 1985 .

[38]  J. Dieterich.  A constitutive law for rate of earthquake production and its application to earthquake clustering , 1994 .

[39]  J. C. Savage.  The Parkfield prediction fallacy , 1993, Bulletin of the Seismological Society of America.

[40]  S. A. Miller.  Fluid-mediated influence of adjacent thrusting on the seismic cycle at Parkfield , 1996, Nature.

[41]  F. Waldhauser,et al.  Slip‐parallel seismic lineations on the Northern Hayward Fault, California , 1999 .

[42]  P. Reasenberg,et al.  Statistical methods for investigating quiescence and other temporal seismicity patterns , 1988 .

[43]  J. Dieterich,et al.  Implications of fault constitutive properties for earthquake prediction. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[44]  A. Rubin,et al.  Streaks of microearthquakes along creeping faults , 1999, Nature.