Major southern San Andreas earthquakes modulated by lake

Dec 07, 2023

Nature (2023)Cite this article

46 Altmetric

Metrics details

Hydrologic loads can stimulate seismicity in the Earth's crust1. However, evidence for the triggering of large earthquakes remains elusive. The southern San Andreas Fault (SSAF) in Southern California lies next to the Salton Sea2, a remnant of ancient Lake Cahuilla that periodically filled and desiccated over the past millennium3,4,5. Here we use new geologic and palaeoseismic data to demonstrate that the past six major earthquakes on the SSAF probably occurred during highstands of Lake Cahuilla5,6. To investigate possible causal relationships, we computed time-dependent Coulomb stress changes7,8 due to variations in the lake level. Using a fully coupled model of a poroelastic crust9,10,11 overlying a viscoelastic mantle12,13, we find that hydrologic loads increased Coulomb stress on the SSAF by several hundred kilopascals and fault-stressing rates by more than a factor of 2, which is probably sufficient for earthquake triggering7,8. The destabilizing effects of lake inundation are enhanced by a nonvertical fault dip14,15,16,17, the presence of a fault damage zone18,19 and lateral pore-pressure diffusion20,21. Our model may be applicable to other regions in which hydrologic loading, either natural8,22 or anthropogenic1,23, was associated with substantial seismicity.

This is a preview of subscription content, access via your institution

Access Nature and 54 other Nature Portfolio journals

Get Nature+, our best-value online-access subscription

$29.99 / 30 days

cancel any time

Subscribe to this journal

Receive 51 print issues and online access

$199.00 per year

only $3.90 per issue

Rent or buy this article

Get just this article for as long as you need it

$39.95

Prices may be subject to local taxes which are calculated during checkout

The Abaqus data files, Lake Cahuilla and Salton Sea data files and processed model results are available on Zenodo (http://doi.org/10.5281/zenodo.7714217). Source data are provided with this paper.

All relevant MATLAB post-processing codes and sample-plotting codes are available on Zenodo (http://doi.org/10.5281/zenodo.7714217).

Talwani, P. On the nature of reservoir-induced seismicity. Pure Appl. Geophys. 150, 473–492 (1997).

Article ADS Google Scholar

Tostrud, M. B. The Salton Sea, 1906-1996, Computed and Measured Salinities and Water Levels. Draft Report, Colorado River Board of California (1997).

Waters, M. R. Late Holocene lacustrine chronology and archaeology of ancient Lake Cahuilla, California. Quat. Res. 19, 373–387 (1983).

Article Google Scholar

Philibosian, B., Fumal, T. & Weldon, R. San Andreas fault earthquake chronology and Lake Cahuilla history at Coachella, California. Bull. Seismol. Soc. Am. 101, 13–38 (2011).

Article Google Scholar

Rockwell, T. K., Meltzner, A. J. & Haaker, E. C. Dates of the two most recent surface ruptures on the southernmost San Andreas fault recalculated by precise dating of Lake Cahuilla dry periods. Bull. Seismol. Soc. Am. 108, 2634–2649 (2018).

Article Google Scholar

Rockwell, T. K., Meltzner, A. J., Haaker, E. C. & Madugo, D. The late Holocene history of Lake Cahuilla: two thousand years of repeated fillings within the Salton Trough, Imperial Valley, California. Quat. Sci. Rev. 282, 107456 (2022).

Article Google Scholar

King, G. C. P., Stein, R. S. & Lin, J. Static stress changes and the triggering of earthquakes. Bull. Seismol. Soc. Am. 84, 935–953 (1994).

Google Scholar

Cocco, M. Pore pressure and poroelasticity effects in Coulomb stress analysis of earthquake interactions. J. Geophys. Res. Solid Earth 107, 2030 (2002).

Article ADS Google Scholar

Rice, J. R. & Cleary, M. P. Some basic stress diffusion solutions for fluid-saturated elastic porous media with compressible constituents. Rev. Geophys. 14, 227–241 (1976).

Article ADS Google Scholar

Wang, H. Theory of Linear Poroelasticity: With Applications to Geomechanics and Hydrogeology (Princeton Univ. Press, 2000).

LaBonte, A., Brown, K. & Fialko, Y. Hydrogeologic detection and finite-element modeling of a slow slip event in the Costa Rica prism toe. J. Geophys. Res. Solid Earth 114, B00A02 (2009).

Article ADS Google Scholar

Segall, P. Earthquake and Volcano Deformation (Princeton Univ. Press, 2010).

Barbot, S. & Fialko, Y. A unified continuum representation of post-seismic relaxation mechanisms: semi-analytic models of afterslip, poroelastic rebound and viscoelastic flow. Geophys. J. Int. 182, 1124–1140 (2010).

Article ADS Google Scholar

Fialko, Y. Interseismic strain accumulation and the earthquake potential on the southern San Andreas fault system. Nature 441, 968–971 (2006).

Article ADS CAS PubMed Google Scholar

Lin, G., Shearer, P. M. & Hauksson, E. Applying a three-dimensional velocity model, waveform cross correlation, and cluster analysis to locate southern California seismicity from 1981 to 2005. J. Geophys. Res. Solid Earth 112, B12309 (2007).

Article ADS Google Scholar

Fuis, G. S., Scheirer, D. S., Langenheim, V. E. & Kohler, M. D. A new perspective on the geometry of the San Andreas fault in Southern California and its relationship to lithospheric structure. Bull. Seismol. Soc. Am. 102, 236–251 (2012).

Article Google Scholar

Lindsey, E. O. et al. Interseismic strain localization in the San Jacinto fault zone. Pure Appl. Geophys. 171, 2937–2954 (2014).

Article ADS Google Scholar

Fialko, Y. et al. Deformation on nearby faults induced by the 1999 Hector Mine earthquake. Science 297, 1858–1862 (2002).

Article ADS CAS PubMed Google Scholar

Cochran, E. S. et al. Seismic and geodetic evidence for extensive, long-lived fault damage zones. Geology 37, 315–318 (2009).

Article ADS Google Scholar

Caine, J. S., Evans, J. P. & Forster, C. B. Fault zone architecture and permeability structure. Geology 24, 1025–1028 (1996).

2.3.CO;2" data-track-action="article reference" href="https://doi.org/10.1130%2F0091-7613%281996%29024%3C1025%3AFZAAPS%3E2.3.CO%3B2" aria-label="Article reference 20" data-doi="10.1130/0091-7613(1996)0242.3.CO;2">Article ADS Google Scholar

Bense, V., Gleeson, T., Loveless, S., Bour, O. & Scibek, J. Fault zone hydrogeology. Earth Sci. Rev. 127, 171–192 (2013).

Article ADS Google Scholar

Nof, R. et al. Rising of the lowest place on Earth due to Dead Sea water-level drop: evidence from SAR interferometry and GPS. J. Geophys. Res. Solid Earth 117, B05412 (2012).

Article ADS Google Scholar

Gupta, H. K. Reservoir Induced Earthquakes (Elsevier, 1992).

Weldon, R. J., Fumal, T. E., Biasi, G. P. & Scharer, K. M. Past and future earthquakes on the San Andreas fault. Science 308, 966–967 (2005).

Article CAS PubMed Google Scholar

Field, E. H. et al. Uniform California Earthquake Rupture Forecast, version 3 (UCERF3)—the time-independent model. Bull. Seismol. Soc. Am. 104, 1122–1180 (2014).

Article Google Scholar

Fumal, T. E. Timing of large earthquakes since AD 800 on the Mission Creek strand of the San Andreas fault zone at Thousand Palms Oasis, near Palm Springs, California. Bull. Seismol. Soc. Am. 92, 2841–2860 (2002).

Article Google Scholar

Gurrola, L. D. & Rockwell, T. K. Timing and slip for prehistoric earthquakes on the Superstition Mountain fault, Imperial Valley, southern California. J. Geophys. Res. Solid Earth 101, 5977–5985 (1996).

Article Google Scholar

Thomas, A. P. & Rockwell, T. K. A 300- to 550-year history of slip on the Imperial fault near the U.S.-Mexico border: missing slip at the Imperial fault bottleneck. J. Geophys. Res. Solid Earth 101, 5987–5997 (1996).

Article Google Scholar

Luttrell, K., Sandwell, D., Smith-Konter, B., Bills, B. & Bock, Y. Modulation of the earthquake cycle at the southern San Andreas fault by lake loading. J. Geophys. Res. Solid Earth 112, B08411 (2007).

Article ADS Google Scholar

Brothers, D., Kilb, D., Luttrell, K., Driscoll, N. & Kent, G. Loading of the San Andreas fault by flood-induced rupture of faults beneath the Salton Sea. Nat. Geosci. 4, 486–492 (2011).

Article ADS CAS Google Scholar

Sieh, K. Slip rate across the San Andreas fault and prehistoric earthquakes at Indio, California. Eos Trans. AGU 67, 1200 (1986).

Google Scholar

Mueller, K. Neotectonics, Alluvial History and Soil Chronology of the Southwestern Margin of the Sierra de Los Cucapas, Baja California Norte. Master's thesis, San Diego State Univ. (1984).

Bronk Ramsey, C. Bayesian analysis of radiocarbon dates. Radiocarbon 51, 337–360 (2009).

Article Google Scholar

Reimer, P. J. et al. The IntCal20 Northern Hemisphere radiocarbon age calibration curve (0–55 cal kBP). Radiocarbon 62, 725–757 (2020).

Article CAS Google Scholar

Roeloffs, E. Fault stability changes induced beneath a reservoir with cyclic variations in water level. J. Geophys. Res. Solid Earth 93, 2107–2124 (1988).

Article Google Scholar

Segall, P. Earthquakes triggered by fluid extraction. Geology 17, 942–946 (1989).

2.3.CO;2" data-track-action="article reference" href="https://doi.org/10.1130%2F0091-7613%281989%29017%3C0942%3AETBFE%3E2.3.CO%3B2" aria-label="Article reference 36" data-doi="10.1130/0091-7613(1989)0172.3.CO;2">Article ADS Google Scholar

Gupta, H. K. A review of recent studies of triggered earthquakes by artificial water reservoirs with special emphasis on earthquakes in Koyna, India. Earth Sci. Rev. 58, 279–310 (2002).

Article ADS Google Scholar

Rajendran, K. & Talwani, P. The role of elastic, undrained, and drained responses in triggering earthquakes at Monticello Reservoir, South Carolina. Bull. Seismol. Soc. Am. 82, 1867–1888 (1992).

Article Google Scholar

Simpson, D., Leith, W. & Scholz, C. Two types of reservoir-induced seismicity. Bull. Seismol. Soc. Am. 78, 2025–2040 (1988).

Article Google Scholar

Tao, W., Masterlark, T., Shen, Z. & Ronchin, E. Impoundment of the Zipingpu reservoir and triggering of the 2008 Mw 7.9 Wenchuan earthquake, China. J. Geophys. Res. Solid Earth 120, 7033–7047 (2015).

Article ADS PubMed PubMed Central Google Scholar

Mitchell, T. & Faulkner, D. The nature and origin of off-fault damage surrounding strike-slip fault zones with a wide range of displacements: a field study from the Atacama fault system, northern Chile. J. Struct. Geol. 31, 802–816 (2009).

Article ADS Google Scholar

Dor, O., Ben-Zion, Y., Rockwell, T. & Brune, J. Pulverized rocks in the Mojave section of the San Andreas Fault Zone. Earth Planet. Sci. Lett. 245, 642–654 (2006).

Article ADS CAS Google Scholar

Rockwell, T. et al. Chemical and physical characteristics of pulverized Tejon Lookout granite adjacent to the San Andreas and Garlock faults: implications for earthquake physics. Pure Appl. Geophys. 166, 1725–1746 (2009).

Article ADS Google Scholar

Morton, N., Girty, G. H. & Rockwell, T. K. Fault zone architecture of the San Jacinto fault zone in Horse Canyon, southern California: a model for focused post-seismic fluid flow and heat transfer in the shallow crust. Earth Planet. Sci. Lett. 329, 71–83 (2012).

Article ADS Google Scholar

Rempe, M. et al. Damage and seismic velocity structure of pulverized rocks near the San Andreas Fault. J. Geophys. Res. Solid Earth 118, 2813–2831 (2013).

Article ADS Google Scholar

Morrow, C., Lockner, D., Moore, D. & Hickman, S. Deep permeability of the San Andreas fault from San Andreas fault observatory at depth (SAFOD) core samples. J. Struct. Geol. 64, 99–114 (2014).

Article ADS Google Scholar

Xue, L., Brodsky, E. E., Erskine, J., Fulton, P. M. & Carter, R. A permeability and compliance contrast measured hydrogeologically on the San Andreas Fault. Geochem. Geophys. Geosyst. 17, 858–871 (2016).

Article ADS Google Scholar

USGS and California Geological Survey. Quaternary Fault and Fold Database for the United States (accessed 10 July 2019); https://www.usgs.gov/natural-hazards/earthquake-hazards/faults/.

Schulte Pelkum, V., Ross, Z. E., Mueller, K. & Ben Zion, Y. Tectonic inheritance with dipping faults and deformation fabric in the brittle and ductile southern California crust. J. Geophys. Res. Solid Earth 125, e2020JB019525 (2020).

Article ADS Google Scholar

Goebel, T., Weingarten, M., Chen, X., Haffener, J. & Brodsky, E. The 2016 Mw5.1 Fairview, Oklahoma earthquakes: Evidence for long-range poroelastic triggering at >40 km from fluid disposal wells. Earth Planet. Sci. Lett. 472, 50–61 (2017).

Article ADS CAS Google Scholar

Verdecchia, A., Cochran, E. S. & Harrington, R. M. Fluid-earthquake and earthquake-earthquake interactions in Southern Kansas, USA. J. Geophys. Res. Solid Earth 126, e2020JB020384 (2021).

Article ADS Google Scholar

Toda, S., Stein, R. S. & Sagiya, T. Evidence from the AD 2000 Izu islands earthquake swarm that stressing rate governs seismicity. Nature 419, 58–61 (2002).

Article ADS CAS PubMed Google Scholar

Qin, Y., Chen, T., Ma, X. & Chen, X. Forecasting induced seismicity in Oklahoma using machine learning methods. Sci. Rep. 12, 9319 (2022).

Article ADS CAS PubMed PubMed Central Google Scholar

Lindsey, E. & Fialko, Y. Geodetic slip rates in the southern San Andreas Fault system: effects of elastic heterogeneity and fault geometry. J. Geophys. Res. Solid Earth 118, 689–697 (2013).

Article ADS Google Scholar

Blanton, C. M., Rockwell, T. K., Gontz, A. & Kelly, J. T. Refining the spatial and temporal signatures of creep and co-seismic slip along the southern San Andreas Fault using very high resolution UAS imagery and SfM-derived topography, Coachella Valley, California. Geomorphology 357, 107064 (2020).

Article Google Scholar

Jin, Z. & Fialko, Y. Finite slip models of the 2019 Ridgecrest earthquake sequence constrained by space geodetic data and aftershock locations. Bull. Seismol. Soc. Am. 110, 1660–1679 (2020).

Article Google Scholar

Eissa, E. & Kazi, A. Relation between static and dynamic Young's moduli of rocks. Int. J. Rock Mech. Min. Geomech. Abstr. 25, 479–482 (1988).

Article Google Scholar

Salditch, L. et al. Earthquake supercycles and long-term fault memory. Tectonophysics 774, 228289 (2020).

Article Google Scholar

Meltzner, A. J. & Wald, D. J. Aftershocks and triggered events of the great 1906 California earthquake. Bull. Seismol. Soc. Am. 93, 2160–2186 (2003).

Article Google Scholar

Byerlee, J. Friction of rock. Pure Appl. Geophys. 116, 615–626 (1978).

Article ADS Google Scholar

Sibson, R. H. An assessment of field evidence for ‘Byerlee’ friction. Pure Appl. Geophys. 142, 645–662 (1994).

Article ADS Google Scholar

Fialko, Y. & Jin, Z. Simple shear origin of the cross-faults ruptured in the 2019 Ridgecrest earthquake sequence. Nat. Geosci. 14, 513–518 (2021).

Article ADS CAS Google Scholar

Fialko, Y. Estimation of absolute stress in the hypocentral region of the 2019 Ridgecrest, California, earthquakes. J. Geophys. Res. Solid Earth 126, e2021JB022000 (2021).

Article ADS Google Scholar

Lockner, D. A., Morrow, C., Moore, D. & Hickman, S. Low strength of deep San Andreas fault gouge from SAFOD core. Nature 472, 82–85 (2011).

Article ADS CAS PubMed Google Scholar

Mitchell, E., Fialko, Y. & Brown, K. M. Temperature dependence of frictional healing of Westerly granite: experimental observations and numerical simulations. Geochem. Geophys. Geosyst. 14, 567–582 (2013).

Article ADS Google Scholar

Mitchell, E., Fialko, Y. & Brown, K. Frictional properties of gabbro at conditions corresponding to slow slip events in subduction zones. Geochem. Geophys. Geosyst. 16, 4006–4020 (2015).

Article ADS Google Scholar

Papazafeiropoulos, G., Muñiz-Calvente, M. & Martínez-Pañeda, E. Abaqus2Matlab: a suitable tool for finite element post-processing. Adv. Eng. Softw. 105, 9–16 (2017).

Article Google Scholar

Durham, W. B. Laboratory observations of the hydraulic behavior of a permeable fracture from 3800 m depth in the KTB pilot hole. J. Geophys. Res. Solid Earth 102, 18405–18416 (1997).

Article Google Scholar

Miller, S. A. The role of fluids in tectonic and earthquake processes. Adv. Geophys. 54, 1–46 (2013).

Article ADS CAS Google Scholar

Chang, K. W. & Segall, P. Injection-induced seismicity on basement faults including poroelastic stressing. J. Geophys. Res. Solid Earth 121, 2708–2726 (2016).

Article ADS Google Scholar

Ge, S. Comment on "Evidence that the 2008 Mw 7.9 Wenchuan earthquake could not have been induced by the Zipingpu Reservoir" by Kai Deng, Shiyong Zhou, Rui Wang, Russell Robinson, Cuiping Zhao, and Wanzheng Cheng. Bull. Seismol. Soc. Am. 101, 3117–3118 (2011).

Article Google Scholar

Biot, M. A. General theory of three dimensional consolidation. J. Appl. Phys. 12, 155–164 (1941).

Article ADS MATH Google Scholar

Dassault Systèmes. Abaqus 2019 (Dassault Systèmes, 2019, 2020).

Tompson, A. et al. Groundwater Availability Within the Salton Sea Basin Final Report (Lawrence Livermore National Laboratory, 2008).

Allam, A. A. & Ben-Zion, Y. Seismic velocity structures in the southern California plate-boundary environment from double-difference tomography. Geophys. J. Int. 190, 1181–1196 (2012).

Article ADS Google Scholar

Shmonov, V., Vitiovtova, V., Zharikov, A. & Grafchikov, A. Permeability of the continental crust: implications of experimental data. J. Geochem. Explor. 78-79, 697–699 (2003).

Article CAS Google Scholar

Richards-Dinger, K. B. & Shearer, P. M. Estimating crustal thickness in southern California by stacking PmP arrivals. J. Geophys. Res. Solid Earth 102, 15211–15224 (1997).

Article Google Scholar

Lundgren, P. E., Hetland, A., Liu, Z. & Fielding, E. J. Southern San Andreas-San Jacinto fault system slip rates estimated from earthquake cycle models constrained by GPS and interferometric synthetic aperture radar observations. J. Geophys. Res. Solid Earth 114, B02403 (2009).

Article ADS Google Scholar

Pearse, J. & Fialko, Y. Mechanics of active magmatic intraplating in the Rio Grande Rift near Socorro, New Mexico. J. Geophys. Res. Solid Earth 115, B07413 (2010).

Article ADS Google Scholar

Johnson, K. Slip rates and off-fault deformation in Southern California inferred from GPS data and models. J. Geophys. Res. Solid Earth 118, 5643–5664 (2013).

Article ADS Google Scholar

Hampel, A., Lüke, J., Krause, T. & Hetzel, R. Finite-element modelling of glacial isostatic adjustment (GIA): use of elastic foundations at material boundaries versus the geometrically non-linear formulation. Comput. Geosci. 122, 1–14 (2019).

Article ADS Google Scholar

Brace, W. F. Permeability of crystalline and argillaceous rocks. Int. J. Rock Mech. Min. Sci. Geomech. Abstr. 17, 241–251 (1980).

Article Google Scholar

Ross, Z. E., Cochran, E. S., Trugman, D. T. & Smith, J. D. 3D fault architecture controls the dynamism of earthquake swarms. Science 368, 1357–1361 (2020).

Article ADS MathSciNet CAS PubMed MATH Google Scholar

Jeppson, T. N., Bradbury, K. K. & Evans, J. P. Geophysical properties within the San Andreas Fault Zone at the San Andreas Fault Observatory at Depth and their relationships to rock properties and fault zone structure. J. Geophys. Res. Solid Earth 115, B12423 (2010).

Article ADS Google Scholar

Farr, T. & Kobrick, M. Shuttle Radar Topography Mission produces a wealth of data. Eos 81, 583–585 (2000).

Article ADS Google Scholar

Pollitz, F. F. & Sacks, I. S. The 1995 Kobe, Japan, earthquake: a long-delayed aftershock of the offshore 1944 Tonankai and 1946 Nankaido earthquakes. Bull. Seismol. Soc. Am. 87, 1–10 (1997).

Article Google Scholar

Savage, J. & Burford, R. Geodetic determination of relative plate motion in central California. J. Geophys. Res. 78, 832–845 (1973).

Article ADS Google Scholar

Lin, G., Shearer, P. M. & Hauksson, E. Applying a three-dimensional velocity model, waveform cross correlation, and cluster analysis to locate southern California seismicity from 1981 to 2005. J. Geophys. Res. Solid Earth 112, B12309 (2007).

Article ADS Google Scholar

Lindsey, E. O. & Fialko, Y. Geodetic constraints on frictional properties and earthquake hazard in the Imperial Valley, Southern California. J. Geophys. Res. Solid Earth 121, 1097–1113 (2016).

Article ADS Google Scholar

Takeuchi, C. & Fialko, Y. Dynamic models of interseismic deformation and stress transfer from plate motion to continental transform faults. J. Geophys. Res. Solid Earth 117, B05403 (2012).

Article ADS Google Scholar

Turcotte, D. L. & Schubert, G. Geodynamics 2nd edn (Cambridge Univ. Press, 2002).

Download references

This work was supported by the Southern California Earthquake Center (grant 21091) to M.W. and NSF (EAR-1841273), NASA (80NSSC22K0506) and USGS (G20AP00051) to Y.F. This research benefited from correspondence with R. Guyer. This project used Quaternary fault data from the USGS. We acknowledge use of the CSRC high-performance computing cluster at San Diego State University.

Department of Geological Sciences, San Diego State University, San Diego, CA, USA

Ryley G. Hill, Matthew Weingarten & Thomas K. Rockwell

Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA

Ryley G. Hill & Yuri Fialko

You can also search for this author in PubMed Google Scholar

You can also search for this author in PubMed Google Scholar

You can also search for this author in PubMed Google Scholar

You can also search for this author in PubMed Google Scholar

R.G.H. constructed the finite-element model, performed analysis of the model results and wrote the manuscript. M.W. managed the study, assisted with building the model, provided access to the modelling software, acquired funding, helped conceive the experiment and commented on the manuscript. T.K.R. carried out the palaeoseismic analysis, conceived the experiment and contributed to the manuscript. Y.F. provided advice on modelling and interpretation of the model results and contributed to the manuscript.

Correspondence to Ryley G. Hill.

The authors declare no competing interests.

Nature thanks the anonymous reviewers for their contribution to the peer review of this work. Peer reviewer reports are available.

Publisher's note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Results of Monte Carlo statistical testing (10,000 samples) based on sampling earthquake PDF distributions and lake timings. After sampling the earthquake PDFs, we determine how many fall inside the lake timings when the lake was greater than 70% full. We compare these timings to a uniform random distribution of seven times across the same lake-loading-time range. We find that the mean timings that occur within lakes is >97% of the earthquake timings of a uniform random distribution that occur within lakes.

3D finite-element method model domain. The model mesh contains about 2 million tetrahedron elements. The light blue colour represents the extent of ancient Lake Cahuilla. The prescribed vertical load is hydrostatic, to the lake maximum water head (97.2 m). The solid red line is the SSAF fault trace. The fault zone is modelled as a slab dipping to the northeast at 60° (ref. 54), with the assumed thickness of 200 m (refs. 19,46,84).

Pore pressure (MPa) on the SSAF as a function of time (year CE) at 7 km depth for location 21, a point on the fault near the centre of the lake (see Supplementary Fig. 5). Each model is based on the variable fault permeability, with model 1 as the most permeable and model 5 as the no damage zone (Extended Data Table 2).

1D analytical model of pore pressure for a variety of different depths (blue) with surface lake-level pore pressure (black). The smaller surface profile from 1905 to the present is the Salton Sea2. Finite-element method model 2 at 7.2 km depth (green line) shows the effect of 3D diffusion with a high-permeability fault damage zone embedded in a lower-permeability host rock. The finite-element method model at 7.2 km resembles pore pressure in the 1D analytical case at 1 km, demonstrating how a fault damage zone can transmit pore pressure to depth effectively. γ = 0.1685; kfault = 1e−15 (m2); khost/1Dmodel = 1e−18 (m2).

Similar to Fig. 4a but for a point farther away from the lake centre (point 24 in Supplementary Fig. 5).

The instantaneous and transient effects of the undrained and drained effects. At t = 0, the undrained effect is felt almost instantaneously throughout the poroelastic medium beneath the lake. As time progresses, this effect attempts to equilibrate at depth. At t = 0, the drained effect is not felt except for the surface poroelastic medium and the bottom of the lake. As time progresses, this effect increases pore pressure as diffusion drives fluid from the surface down. Furthermore, as the lake load is applied, areas of compression form immediately beneath the lake, whereas areas of extension are formed near the edges.

This file contains Supplementary Figs. 1–11.

Calculation of probable age ranges based on radiocarbon measurements from Rockwell et al.6.

Spatiotemporal pore-pressure evolution. This video describes the change in relative pore pressure across the SSAF for each time step in our model of the six lake-loading cycles of ancient Lake Cahuilla that also includes the load of the Salton Sea. The * point on the fault is the location of maximum pore pressure for average seismogenic depth of 7 km. The pore pressure at each step associated with * is plotted on the right. Two other curves are plotted that represent a ratio of what portion of the fault has positive pore pressure. The black line is for pore pressure at 7 km depth and the grey line is for pore pressure across the entire fault.

Spatiotemporal CFS evolution. This description is the same as for Supplementary Video 1 except for CFS instead of pore pressure.

Positive/negative CFS evolution. This video describes the binary positive CFS (red) versus negative CFS (blue) across the SSAF for each time step in our model. A black * plotted on the fault plane represents the location at each time step with the maximum CFS for the entire fault. Two lines are plotted on the right, which represent the positive (red) versus negative (blue) ratio for CFS on the SSAF.

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and Permissions

Hill, R.G., Weingarten, M., Rockwell, T.K. et al. Major southern San Andreas earthquakes modulated by lake-filling events. Nature (2023). https://doi.org/10.1038/s41586-023-06058-9

Download citation

Received: 15 July 2022

Accepted: 05 April 2023

Published: 07 June 2023

DOI: https://doi.org/10.1038/s41586-023-06058-9

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.