Detecting Significant Stress Drop Variations in Large Micro-Earthquake Datasets: A Comparison Between a Convergent Step-Over in the San Andreas Fault and the Ventura Thrust Fault System, Southern California
A key parameter in engineering seismology and earthquake physics is seismic stress drop, which describes the relative amount of high-frequency energy radiation at the source. To identify regions with potentially significant stress drop variations, we perform a comparative analysis of source parameters in the greater San Gorgonio Pass (SGP) and Ventura basin (VB) in southern California. The identification of physical stress drop variations is complicated by large data scatter as a result of attenuation, limited recording bandwidth and imprecise modeling assumptions. In light of the inherently high uncertainties in single stress drop measurements, we follow the strategy of stacking large numbers of source spectra thereby enhancing the resolution of our method. We analyze more than 6000 high-quality waveforms between 2000 and 2014, and compute seismic moments, corner frequencies and stress drops. Significant variations in stress drop estimates exist within the SGP area. Moreover, the SGP also exhibits systematically higher stress drops than VB and shows more scatter. We demonstrate that the higher scatter in SGP is not a generic artifact of our method but an expression of differences in underlying source processes. Our results suggest that higher differential stresses, which can be deduced from larger focal depth and more thrust faulting, may only be of secondary importance for stress drop variations. Instead, the general degree of stress field heterogeneity and strain localization may influence stress drops more strongly, so that more localized faulting and homogeneous stress fields favor lower stress drops. In addition, higher loading rates, for example, across the VB potentially result in stress drop reduction whereas slow loading rates on local fault segments within the SGP region result in anomalously high stress drop estimates. Our results show that crustal and fault properties systematically influence earthquake stress drops of small and large events and should be considered for seismic hazard assessment.
KeywordsStress field heterogeneity source parameter inversion spatial stress drop variation asperity strength slip rates
The initial manuscript benefitted from comments by Xiaowei Chen and Grzegorz Kwiatek. We would like to thank Michele Cooke for her detailed review. T. Goebel and E. Hauksson were supported by NEHRP/USGS grant G15AP00095 and the Southern California Earthquake Center (SCEC) under contribution number 12017 and 14033. SCEC is funded by NSF Cooperative Agreement EAR-0529922 and USGS Cooperative Agreement 07HQAG0008. We have used waveforms and parametric data from the Caltech/USGS Southern California Seismic Network (SCSN); DOI: 10.7914/SN/CI; stored at the Southern California Earthquake Center. DOI: 10.7909/C3WD3xH1.
- Abercrombie, R. E. (1995), Earthquake source scaling relationships from −1 using seismograms recorded at 2.5 km depth, J. Geophys. Res., 100(B12), 24,015–36.Google Scholar
- Abercrombie, R. E. (2013), Comparison of direct and coda wave stress drop measurements for the Wells, Nevada, earthquake sequence, J. Geophy. Res., 118, doi: 10.1029/2012JB009638.
- Abercrombie, R. E. (2015), Investigating uncertainties in empirical green’s function analysis of earthquake source parameters, J. Geophy. Res., 120, doi: 10.1002/2015JB011984.
- Aki, K. (1967), Scaling law of seismic spectrum, J. Geophys. Res., 72, 1217–1231.Google Scholar
- Allmann, B. P., and P. M. Shearer (2007), Spatial and temporal stress drop variations in small earthquakes near Parkfield, California, J. Geophs. Res., 112(B4), B04,305.Google Scholar
- Allmann, B. P., and P. M. Shearer (2009), Global variations of stress drop for moderate to large earthquakes, J. Geophys. Res., 114(B1), B01,310.Google Scholar
- Andrews, D. J. (1986), Objective determination of source parameters and similarity of earthquakes of different size, in Earthquake Source Mechanics, pp. 259–267, doi: 10.1029/GM037p0259.
- Atkinson, G. M., and I. Beresnev (1997), Don’t call it stress drop, Seismological Research Letters, 68(1), 3–4.Google Scholar
- Beeler, N. M., S. H. Hickman, and T.-f. Wong (2001), Earthquake stress drop and laboratory-inferred interseismic strength recovery, J. Geophys. Res., 106(B12), 30,701–30,713.Google Scholar
- Beresnev, I. A. (2009), The reality of the scaling law of earthquake-source spectra?, J. Seismol., 13(4), 433–436.Google Scholar
- Brune, J. N. (1970), Tectonic stress and the spectra of seismic shear waves from earthquakes, J. Geophys. Res., 75(26), 4997–5009.Google Scholar
- Burgette, R. J., K. M. Johnson, and W. C. Hammond (2015), Observations of vertical deformation across the western transverse ranges and constraints on ventura area fault slip rates, 2015 SCEC Annual Meeting Abstracts, p. 201.Google Scholar
- Carena, S., J. Suppe, and H. Kao (2004), Lack of continuity of the San Andreas fault in Southern California: Three-dimensional fault models and earthquake scenarios, J. Geophys. Res., 109(B4).Google Scholar
- Catchings, R., M. Rymer, M. Goldman, and G. Gandhok (2009), San Andreas fault geometry at Desert Hot Springs, California, and its effects on earthquake hazards and groundwater, Bull. Seismol. Soc. Am., 99(4), 2190–2207.Google Scholar
- Chen, X., and P. M. Shearer (2013), California foreshock sequences suggest aseismic triggering process, Geophys. Res. Letts., 40(11), 2602–2607.Google Scholar
- Clauset, A., C. R. Shalizi, and M. E. J. Newmann (2009), Power-law distributions in empirical data, SIAM review, 51(4), 661–703.Google Scholar
- Cooke, M. L., and L. C. Dair (2011), Simulating the recent evolution of the southern big bend of the San Andreas fault, Southern California, J. Geophys. Res., 116(B4).Google Scholar
- Dair, L., and M. L. Cooke (2009), San Andreas fault geometry through the San Gorgonio Pass, California, Geology, 37(2), 119–122.Google Scholar
- Donnellan, A., B. H. Hager, and R. W. King (1993), Discrepancy between geological and geodetic deformation rates in the Ventura Basin, Nature, 366(6453), 333–336.Google Scholar
- Eshelby, J. D. (1957), The determination of the elastic field of an ellipsoidal inclusion, and related problems, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 241(1226), 376–396.Google Scholar
- Goebel, T. H. W., C. G. Sammis, T. W. Becker, G. Dresen, and D. Schorlemmer (2013a), A comparison of seismicity characteristics and fault structure in stick-slip experiments and nature, Pure Appl. Geophys., doi: 10.1007/s00024-013-0713-7.
- Goebel, T. H. W., D. Schorlemmer, T. W. Becker, G. Dresen, and C. G. Sammis (2013b), Acoustic emissions document stress changes over many seismic cycles in stick-slip experiments, Geophys. Res. Letts., 40, doi: 10.1002/grl.50507.
- Goebel, T. H. W., E. Hauksson, J.-P. Ampuero, and P. M. Shearer (2015), Stress drop heterogeneity within tectonically complex regions: A case study of San Gorgonio Pass, southern California, Geophys. J. Int., 202(1), 514–528, DOI 10.1093/gji/ggv160.Google Scholar
- Goertz-Allmann, B. P., A. Goertz, and S. Wiemer (2011), Stress drop variations of induced earthquakes at the basel geothermal site, Geophys. Res. Letts., 38(9).Google Scholar
- Goodfellow, S., and R. Young (2014), A laboratory acoustic emission experiment under in situ conditions, Geophysical Research Letters, 41(10), 3422–3430.Google Scholar
- Graves, R. W., B. T. Aagaard, K. W. Hudnut, L. M. Star, J. P. Stewart, and T. H. Jordan (2008), Broadband simulations for M_w 7.8 southern San Andreas earthquakes: Ground motion sensitivity to rupture speed, Geophys. Res. Lett., 35(22).Google Scholar
- Gu, Y., and T.-f. Wong (1991), Effects of loading velocity, stiffness, and inertia on the dynamics of a single degree of freedom spring-slider system, J. Geophys. Res., 96(B13), 21,677–21,691.Google Scholar
- Hardebeck, J. L., and A. J. Michael (2006), Damped regional-scale stress inversions: Methodology and examples for southern California and the Coalinga aftershock sequence, Journal of Geophysical Research: Solid Earth (1978–2012), 111(B11).Google Scholar
- Hardebeck, J. L., and P. M. Shearer (2002), A new method for determining first-motion focal mechanisms, Bulletin of the Seismological Society of America, 92(6), 2264–2276.Google Scholar
- Harrington, R. M., and E. E. Brodsky (2009), Source duration scales with magnitude differently for earthquakes on the San Andreas Fault and on secondary faults in Parkfield, California, Bull. Seismol. Soc. Am., 99(4), 2323–2334.Google Scholar
- Hauksson, E. (2014), Average stress drops of southern California earthquakes in the context of crustal geophysics: Implications for fault zone healing, Pure Appl. Geophys., pp. 1–12, doi: 10.1007/s00024-014-0934-4.
- He, C., T.-f. Wong, and N. M. Beeler (2003), Scaling of stress drop with recurrence interval and loading velocity for laboratory-derived fault strength relations, J. Geophys. Res., 108(B1), doi: 10.1029/2002JB001890.
- Hubbard, J., J. H. Shaw, J. Dolan, T. L. Pratt, L. McAuliffe, and T. K. Rockwell (2014), Structure and seismic hazard of the Ventura Avenue Anticline and Ventura Fault, California: Prospect for large, multisegment ruptures in the western Transverse Ranges, Bull. Seismol. Soc. Am., doi: 10.1785/0120130125.
- Kanamori, H., and D. L. Anderson (1975), Theoretical basis of some empirical relations in seismology, Bull. Seismol. Soc. Am., 65, 1073–1095.Google Scholar
- Kanamori, H., J. Mori, E. Hauksson, T. H. Heaton, L. K. Hutton, and L. M. Jones (1993), Determination of earthquake energy release and m_l using terrascope, Bull. Seismol. Soc. Am., 83(2), 330–346.Google Scholar
- Kaneko, Y., and P. M. Shearer (2014), Seismic source spectra and estimated stress drop derived from cohesive-zone models of circular subshear rupture, Geophys. J. Int., doi: 10.1093/gji/ggu030, (in press).
- Kwiatek, G., K. Plenkers, and G. Dresen (2011), Source parameters of picoseismicity recorded at Mponeng deep gold mine, South Africa: implications for scaling relations, Bull. Seism. Soc. Am., 101(6), 2592–2608.Google Scholar
- Langenheim, V. E., R. C. Jachens, J. C. Matti, E. Hauksson, D. M. Morton, and A. Christensen (2005), Geophysical evidence for wedging in the San Gorgonio Pass structural knot, southern San Andreas fault zone, southern California, Geological Society of America Bulletin, 117(11-12), 1554–1572.Google Scholar
- Lin, Y.-Y., K.-F. Ma, and V. Oye (2012), Observation and scaling of microearthquakes from the Taiwan Chelungpu-fault borehole seismometers, Geophys. J. Int., 190(1), 665–676.Google Scholar
- Madariaga, R. (1976), Dynamics of an expanding circular fault, Bull. Seismol. Soc. Am., 66(3), 639–666.Google Scholar
- Magistrale, H., and C. Sanders (1996), Evidence from precise earthquake hypocenters for segmentation of the San Andreas fault in San Gorgonio Pass, J. Geophys. Res., 101(B2), 3031–3044.Google Scholar
- Marone, C. (1998), Laboratory-derived friction laws and their application to seismic faulting, Annu. Rev. Earth Planet. Sci., 26, 643–696.Google Scholar
- Marshall, S. T., G. J. Funning, and S. E. Owen (2013), Fault slip rates and interseismic deformation in the western transverse ranges, california, Journal of Geophysical Research: Solid Earth, 118(8), 4511–4534.Google Scholar
- Martínez-Garzón, P., G. Kwiatek, M. Ickrath, and M. Bohnhoff (2014), MSATSI: A MATLAB package for stress inversion combining solid classic methodology, a new simplified user-handling, and a visualization tool, Seismological Research Letters, 85(4), 896–904.Google Scholar
- Matti, J. C., and D. M. Morton (1993), Paleogeographic evolution of the San Andreas fault in southern California: A reconstruction based on a new cross-fault correlation, Geological Society of America Memoirs, 178, 107–160.Google Scholar
- McLaskey, G. C., A. M. Thomas, S. D. Glaser, and R. M. Nadeau (2012), Fault healing promotes high-frequency earthquakes in laboratory experiments and on natural faults, Nature, 491(7422), 101–104.Google Scholar
- Nadeau, R. M., and L. R. Johnson (1998), Seismological studies at parkfield VI: Moment release rates and estimates of source parameters for small repeating earthquakes, Bull. Seismol. Soc. Am., 88(3), 790–814.Google Scholar
- Oth, A. (2013), On the characteristics of earthquake stress release variations in Japan, Earth and Planetary Science Letters, 377, 132–141.Google Scholar
- Plesch, A., et al. (2007), Community fault model (CFM) for southern California, Bulletin of the Seismological Society of America, 97(6), 1793–1802.Google Scholar
- Prieto, G. A., P. M. Shearer, F. L. Vernon, and D. Kilb (2004), Earthquake source scaling and self-similarity estimation from stacking P and S spectra, J. Geophys. Res., 109(B8).Google Scholar
- Prieto, G. A., D. J. Thomson, F. L. Vernon, P. M. Shearer, and R. L. Parker (2007), Confidence intervals for earthquake source parameters, Geophys. J. Int., 168(3), 1227–1234.Google Scholar
- Rockwell, T. K. (2011), Large co-seismic uplift of coastal terraces across the Ventura Avenue anticline: Implications for the size of earthquakes and the potential for tsunami generation, 2011 Annual Meeting Abstracts, 21, (Plenary talk).Google Scholar
- Rubin, A. M., and J.-P. Ampuero (2005), Earthquake nucleation on (aging) rate and state faults, J. Geophys. Res., 110(B11), doi: 10.1029/2005JB003686.
- Sammis, C. G., and J. R. Rice (2001), Repeating earthquakes as low-stress-drop events at a border between locked and creeping fault patches, Bull. Seismol. Soc. Am., 91(3), 532–537.Google Scholar
- Sato, T., and T. Hirasawa (1973), Body wave spectra from propagating shear cracks, J. Phys. Earth, 21(4), 415–431.Google Scholar
- Scharer, K. M., R. J. Weldon, T. E. Fumal, and G. P. Biasi (2007), Paleoearthquakes on the southern San Andreas fault, Wrightwood, California, 3000 to 1500 BC: A new method for evaluating paleoseismic evidence and earthquake horizons, Bull. Seismol. Soc. Am., 97(4), 1054–1093.Google Scholar
- Schorlemmer, D., S. Wiemer, and M. Wyss (2005), Variations in earthquake-size distribution across different stress regimes, Nature, 437, 539–542, DOI 10.1038/nature04094.Google Scholar
- Shaw, J. H., et al. (2015), Unified structural representation of the southern California crust and upper mantle, Earth and Planetary Science Letters, 415, 1–15.Google Scholar
- Shearer, P. M. (2009), Introduction to seismology, Cambridge University Press.Google Scholar
- Shearer, P. M., G. A. Prieto, and E. Hauksson (2006), Comprehensive analysis of earthquake source spectra in southern California, J. Geophs. Res., 111(B6), B06,303.Google Scholar
- Sibson, R. H. (1974), Frictional constraints on thrust, wrench and normal faults, Nature, 249, 542–544.Google Scholar
- Walter, W. R., K. Mayeda, R. Gok, and A. Hofstetter (2006), The scaling of seismic energy with moment: Simple models compared with observations, Earthquakes: Radiated energy and the physics of faulting, pp. 25–41.Google Scholar
- Warren, L. M., and P. M. Shearer (2000), Investigating the frequency dependence of mantle Q by stacking P and PP spectra, J. Geophys. Res., 105(B11), 25,391–25.Google Scholar
- Wyss, M., C. G. Sammis, R. M. Nadeau, and S. Wiemer (2004), Fractal dimension and b-value on creeping and locked patches of the San Andreas fault near Parkfield, California, Bull. Seismol. Soc. Am., 94, 410–421.Google Scholar
- Yang, W., and E. Hauksson (2011), Evidence for vertical partitioning of strike-slip and compressional tectonics from seismicity, focal mechanisms, and stress drops in the east Los Angeles basin area, California, Bull. Seismol. Soc. Am., 101(3), 964–974.Google Scholar
- Yang, W., and E. Hauksson (2013), The tectonic crustal stress field and style of faulting along the Pacific North America Plate boundary in Southern California, Geophys. J. Int., 194(1), 100–117.Google Scholar
- Yang, W., Z. Peng, and Y. Ben-Zion (2009), Variations of strain-drops of aftershocks of the 1999 İzmit and Düzce earthquakes around the Karadere-Düzce branch of the North Anatolian Fault, Geophys. J. Int., 177(1), 235–246.Google Scholar
- Yeats, R. S. (1983), Large-scale Quaternary detachments in Ventura Basin, southern California, J. Geophys. Res., 88(B1), 569–583.Google Scholar
- Yule, D., and K. Sieh (2003), Complexities of the San Andreas fault near San Gorgonio Pass: Implications for large earthquakes, J. Geophys. Res., 108, doi: 10.1029/2001JB000451.