[SAFOD] SAFOD - San Andreas Fault Zone Observatory at Depth

Climate & Ecosystems
Plate Margins
Natural Hazards

Year of Application: 2007

Expedition ID: 5025

Current Status: completed

active faulting
directional drilling
downhole monitoring
san andreas fault
Master Data

Dr. Thomas Wiersberg (PI)
Prof. Dr. Joerg Erzinger (PI)
Dr. Ute Weckmann (PI)
Dr. Guillaume Desbois (PI)

Dr. Martin Karrenbach (Scientific Participant)
Dr. Christian Haberland (Scientific Participant)
Dr. Susann Berthold (Scientific Participant)
Prof. Dr. Georg Dresen (Scientific Participant)
Dr. Trond Ryberg (Scientific Participant)
Dr. Anton Alexander Popov (Scientific Participant)
Dr. Claus Prodehl (Scientific Participant)
Dr. Kristina Tietze (Scientific Participant)
Dr. Stine Gutjahr (Scientific Participant)
Prof. Dr. Stefan Buske (Scientific Participant)
Dr. Christoph Janssen (Scientific Participant)
Bernhard Prevedel (Scientific Participant)

Projektstart: 6 January, 2004
Geologisches Alter: cretaceous, tertiary

Latitude: 35°58'26''N

North America

Regionen & Städte:

San Andreas Fault

Longitude: 120°33'8''W

United States


hard rock

Drilling Data

Drilling Depth: 7345.0
Core Yield: 62.92
Core Length: 72.05
Amount of Drill Holes: 2
Amount of Drill Locations: 1

Core Length-Drill Depth-Ratio: 0.86
Core Yield-Core Length-Ratio: 87.33

Related DFG-Projects

[Bleibinhaus] High resolution P- and S-wave velocity and attenuation models for the SAFOD site from visco-elastic full seismic waveform inversion of the SAFOD-2003 data (2014 - 2017)

[Janssen] Fault zone damage and chemical reactions at depth in the San Andreas Fault Zone: A study of SAFOD drill core samples (2009 - 2014)

[Buske] Multiscale seismic imaging of the San-Andreas-Fault system (2008 - 2013)

[Erzinger] Geochemistry of gases in seismogenic depths of the San Andreas Fault Zone (2007 - 2010)

[Ritter] The electrical conductivity structure between the transitional (near SAFOD) and locked (SE of Cholame) segments of the San Andreas Fault, including the source region of the non-volcanic tremors (2008 - 2013)

[Buske] Active and Passive Seismic Imaging of the San-Andreas-Fault System (2006 - 2009)

[Ritter] Imaging the deep root of the San Andreas Fault zone at Parkfield, CA, with magnetotelluric measurements (2004 - 2011)

[Schleicher] The importance of clay mineral reactions on the seismic behavior of the San Andreas Fault: Part 2-Hydration states and timing of mineralization (2006 - 2009)

[Ryberg] Voruntersuchungen an der globalen Lokation "San Andreas Fault System" (1997 - 2001)

[Ryberg] Controlled source P- and S-wave tomography at the SAFOD site - direct imaging of petrological and fluid properties (2002 - 2005)

[Erzinger] On the geochemistry of crustal fluids and gases of the San Andreas Fault Zone - Real-time mud gas monitoring during ICDP-SAFOD drilling - (2004 - 2008)

[Sobolev] Evolution of the San Andreas Fault System from the lithospheric-scale 3-D thermo-mechanical modelling constrained by geophysical observations (2004 - 2009)

[Janssen] Fault zone damage and chemical reactions at depth in the San Andreas Fault Zone: A study of SAFOD drill core samples (2011 - 2014)

[Ryberg] Erkundung der Krustenstruktur der San-Andreas-Verwerfungszone im Gebiet der San-Gabriel-Mountains und bei Parkfield, CA, USA (1998 - 2000)

[Prodehl] Erkundung der Krustenstruktur der San-Andreas-Verwerfungszone im Gebiet der San-Gabriel-Mountains und bei Parkfield, California (1998 - 2000)

[Karrenbach] Voruntersuchung an der globalen Lokation "San Andreas Fault System" (1997 - 2002)

[Erzinger] Zur Geochemie der Krustenfluide und -gase in Rift- und Fault-Zonen (ICDP-Bohrungen: Golf von Korinth und San Andreas Fault Zone) (2001 - 2003)

[Janssen] Faulting processes in active faults - Microstructural, mineralogical and geochemical characterization of drill core samples from international drilling projects (2017 - ongoing)

[Janssen] Faulting processes in active faults - Microstructural, mineralogical and geochemical characterization of drill core samples from international drilling projects (2015 - 2019)

[Ikari] The role of cohesion in fault slip style (2021 - ongoing)


Building on more than 15 years of experience from the Parkfield Earthquake Experiment, the National Science Foundation (NSF) and the USGS started in June 2004 to drill a deep hole in order to install instruments directly within the San Andreas Fault Zone near the initiation point of previous magnitude 6 Parkfield earthquakes (drill hole location in relation to slip rate). These instruments, set 2 to 3 km beneath the Earth's surface, will form a San Andreas Fault Observatory at Depth (SAFOD). This project will directly reveal, for the first time, the physical and chemical processes controlling earthquake generation within a seismically active fault.

Drilling the hole for SAFOD starts west of the San Andreas Fault and then use advanced directional-drilling technology developed by the petroleum industry to angle the hole through the entire fault zone until relatively undisturbed rock is reached on the east side. Fault-zone rocks and fluids will be retrieved for laboratory analyses, and geophysical measurments will be made within the active fault zone. SAFOD's long-term monitoring activities will include detailed seismological observations of small to moderate earthquakes and continuous measurements of rock deformation and other parameters during the earthquake cycle.

SAFOD will provide direct information on the composition and mechanical properties of rocks in the fault zone, the nature of stresses responsible for earthquakes, the role of fluids in controlling faulting and earthquake recurrence, and the physics of earthquake initiation and rupture. By observing quakes "up close," SAFOD will mark a major advance in the pursuit of a rigorous scientific basis for assessing earthquake hazards and predicting earthquakes.

SAFOD is funded by NSF as part of an ambitious scientific initiative called EarthScope. The other elements of EarthScope include USArray, and the Plate Boundary Observatory (PBO). USArray consists of a large transportable broadband seismic array, augmented by smaller seismic arrays and coordinated with the USGS Advanced National Seismic System (ANSS). The PBO is a network of deformation sensors (GPS and strainmeters) for the western United States similar to that deployed at Parkfield. Support for scientific studies using SAFOD and the other EarthScope facilities will come through programs within NSF, USGS, NASA, and several foreign countries.

A 2.2-km-deep vertical pilot hole was drilled adjacent to the San Andreas Fault at Parkfield in the summer of 2002. This pilot project was funded by International Continental Drilling Program ICDP, with considerable logistical and scientific help from the  NSF, and USGS. The pilot project  has provided both engineering and scientific data to guide the current SAFOD project to its goal of precisely drilling into the fault-zone where small, M2, earthquakes repeat on a regular schedule.

The cooperative efforts of USGS and other scientists in the Parkfield Earthquake Experiment and SAFOD will help achieve a better understanding of what happens on and near a fault during the earthquake cycle and will aid in predicting the time and severity of future quakes. This work is part of the National Earthquake Hazard Reduction Program's ongoing efforts to protect people's lives and property from the earthquakes that are inevitable in California and elsewhere in the United States.

Related Publications

Sutherland, Rupert, Townend, John, Toy, Virginia, Upton, Phaedra, Coussens, Jamie, Allen, Michael, Baratin, Laura-May, Barth, Nicolas, Becroft, Leeza, Boese, Carolin, Boles, Austin, Boulton, Carolyn, Broderick, Neil G. R., Janku-Capova, Lucie, Carpenter, Brett M., Célérier, Bernard, Chamberlain, Calum, Cooper, Alan, Coutts, Ashley, Cox, Simon, Craw, Lisa, Doan, Mai-Linh, Eccles, Jennifer, Faulkner, Dan, Grieve, Jason, Grochowski, Julia, Gulley, Anton, Hartog, Arthur, Howarth, Jamie, Jacobs, Katrina, Jeppson, Tamara, Kato, Naoki, Keys, Steven, Kirilova, Martina, Kometani, Yusuke, Langridge, Rob, Lin, Weiren, Little, Timothy, Lukacs, Adrienn, Mallyon, Deirdre, Mariani, Elisabetta, Massiot, Cécile, Mathewson, Loren, Melosh, Ben, Menzies, Catriona, Moore, Jo, Morales, Luiz, Morgan, Chance, Mori, Hiroshi, Niemeijer, Andre, Nishikawa, Osamu, Prior, David, Sauer, Katrina, Savage, Martha, Schleicher, Anja, Schmitt, Douglas R., Shigematsu, Norio, Taylor-Offord, Sam, Teagle, Damon, Tobin, Harold, Valdez, Robert, Weaver, Konrad, Wiersberg, Thomas, Williams, Jack, Woodman, Nick, Zimmer, Martin (2017). "Extreme hydrothermal conditions at an active plate-bounding fault" Nature 546 p137

Zeiß, J, Peters-Poethke, KP, Paschke, MP, Bleibinhaus, FB (2017). "Preprocessing for fully elastic 2D waveform inversion of body waves in active seismic data from the San Andreas Fault" 79th EAGE Conference and Exhibition 2017

Ikari, Matt J., Carpenter, Brett M., Vogt, Christoph, Kopf, Achim J. (2016). "Elevated time-dependent strengthening rates observed in San Andreas Fault drilling samples" Earth and Planetary Science Letters 450 p164-172

Janssen, C., Wirth, R., Wenk, H. R., Morales, L., Naumann, R., Kienast, M., Song, S. R., Dresen, G. (2014). "Faulting processes in active faults – Evidences from TCDP and SAFOD drill core samples" Journal of Structural Geology p100-116

Tietze, Kristina, Ritter, Oliver (2013). "Three-dimensional magnetotelluric inversion in practice—the electrical conductivity structure of the San Andreas Fault in Central California" Geophysical Journal International 195 p130-147

Janssen, C., Kanitpanyacharoen, W., Wenk, H. R., Wirth, R., Morales, L., Rybacki, E., Kienast, M., Dresen, G. (2012). "Clay fabrics in SAFOD core samples" Journal of Structural Geology p118-127

Sutherland, R., Toy, V.G., Townend, J., Cox, S.C., Eccles, J.D., Faulkner, D.R., Prior, D.J., Norris, R.J., Mariani, E., Boulton, C., Carpenter, B.M., Menzies, C.D., Little, T.A., Hasting, M., De Pascale, G.P., Langridge, R.M., Scott, H.R., Lindroos, Z. Reid, Fleming, B., Kopf, A.J. (2012). "Drilling reveals fluid control on architecture and rupture of the Alpine fault, New Zealand" Geology 40 p1143-1146

Tietze, Kristina (2012). "Investigating the electrical conductivity structure of the San Andreas fault system in the Parkfield-Cholame region, central California, with 3D magnetotelluric inversion" Dissertation p182

Becken, Michael, Ritter, Oliver (2012). "Magnetotelluric Studies at the San Andreas Fault Zone: Implications for the Role of Fluids" Surveys in Geophysics p65-105

Popov, Anton A., Sobolev, Stephan V., Zoback, Mark D. (2012). "Modeling evolution of the San Andreas Fault system in northern and central California" Geochemistry, Geophysics, Geosystems p1-21

Ryberg, T., Hole, J. A., Fuis, G. S., Rymer, M. J., Bleibinhaus, F., Stromeyer, D., Bauer, K. (2012). "Tomographic Vp and Vs structure of the California Central Coast Ranges, in the vicinity of SAFOD, from controlled-source seismic data" Geophysical Journal International 190 p1341-1360

Wiersberg, Thomas, Erzinger, Jörg (2011). "Chemical and isotope compositions of drilling mud gas from the San Andreas Fault Observatory at Depth (SAFOD) boreholes: Implications on gas migration and the permeability structure of the San Andreas Fault" Chemical Geology 284 p148-159

Ikari, Matt J., Kopf, Achim J. (2011). "Cohesive strength of clay-rich sediment" Geophysical Research Letters 38 p1-5

Becken, Michael, Ritter, Oliver, Bedrosian, Paul A., Weckmann, Ute (2011). "Correlation between deep fluids, tremor and creep along the central San Andreas fault" Nature 480 p87-90

Rybacki, E., Janssen, C., Wirth, R., Chen, K., Wenk, H. R., Stromeyer, D., Dresen, G. (2011). "Low-temperature deformation in calcite veins of SAFOD core samples (San Andreas Fault) — Microstructural analysis and implications for fault rheology" Tectonophysics 509 p107-119

Wenk, Hans-Rudolf, Janssen, Christoph, Kenkmann, Thomas, Dresen, Georg (2011). "Mechanical twinning in quartz: Shock experiments, impact, pseudotachylites and fault breccias" Tectonophysics 510 p69-79

Janssen, Christoph, Wirth, Richard, Reinicke, Andreas, Rybacki, Erik, Naumann, Rudolf, Wenk, Hans-Rudolf, Dresen, Georg (2011). "Nanoscale porosity in SAFOD core samples (San Andreas Fault)" Earth and Planetary Science Letters 301 p179-189

Janssen, C., Wirth, R., Rybacki, E., Naumann, R., Kemnitz, H., Wenk, H. R., Dresen, G. (2010). "Amorphous material in SAFOD core samples (San Andreas Fault): Evidence for crush-origin pseudotachylytes?" Geophysical Research Letters 37 pL01303

Rentsch, S., Buske, S., Gutjahr, S., Kummerow, J., Shapiro, S. A. (2010). "Migration-based location of seismicity recorded with an array installed in the main hole of the San Andreas Fault Observatory at Depth (SAFOD)" Geophysical Journal International p477-492

Schleicher, A.M., van der Pluijm, B.A., Warr, L.N. (2010). "Nanocoatings of clay and creep of the San Andreas fault at Parkfield, California" Geology 38 p667-670

Reshetnikov, A., Buske, S., Shapiro, S. A. (2010). "Seismic imaging using microseismic events: Results from the San Andreas Fault System at SAFOD" Journal of Geophysical Research: Solid Earth 115 pB12324

Schleicher, Anja M., Tourscher, Sara N., van der Pluijm, Ben A., Warr, Laurence N. (2009). "Constraints on mineralization, fluid-rock interaction, and mass transfer during faulting at 2–3 km depth from the SAFOD drill hole" Journal of Geophysical Research: Solid Earth 114 pB04202

Bohnhoff, Marco, Dresen, Georg, Ellsworth, William L, Ito, Hisao (2009). "Passive seismic monitoring of natural and induced earthquakes: case studies, future directions and socio-economic relevance" New Frontiers in Integrated Solid Earth Sciences p261-285

Popov, Anton (2009). "Three-dimensional thermo-mechanical modeling of deformation at plate boundaries: case study San Andreas Fault system" Dissertation

Becken, M., Ritter, O., Park, S. K., Bedrosian, P. A., Weckmann, U., Weber, M. (2008). "A deep crustal fluid channel into the San Andreas Fault system near Parkfield, California" Geophysical Journal International 173 p718-732

Schleicher, A. M., Warr, L. N., van der Pluijm, B. A. (2008). "On the origin of mixed-layered clay minerals from the San Andreas Fault at 2.5–3 km vertical depth (SAFOD drillhole at Parkfield, California)" Contributions to Mineralogy and Petrology 157 p173

Wiersberg, Thomas, Erzinger, Jörg (2008). "Origin and spatial distribution of gas at seismogenic depths of the San Andreas Fault from drill-mud gas analysis" Applied Geochemistry 23 p1675-1690

Parés, Josep M., Schleicher, Anja M., van der Pluijm, Ben A., Hickman, Stephen (2008). "Paleomagnetic reorientation of San Andreas Fault Observatory at Depth (SAFOD) core" Geophysical Research Letters 35 pL02306

Popov, A. A., Sobolev, S. V. (2008). "SLIM3D: A tool for three-dimensional thermomechanical modeling of lithospheric deformation with elasto-visco-plastic rheology" Physics of the Earth and Planetary Interiors p55-75

Wiersberg, Thomas, Erzinger, Jörg (2007). "A helium isotope cross-section study through the San Andreas Fault at seismogenic depths" Geochemistry, Geophysics, Geosystems 8 (1) p1-12

Wiersberg, T., Erzinger, J. (2007). "Hydrogen anomalies at seismogenic depths of the San Andreas Fault" Geochimica Et Cosmochimica Acta 71 pA1110-A1110

Tobin, Harold, Ito, Hisao, Behrmann, Jan Hinrich, Hickman, Stephen, Kimura, Gaku (2007). "IODP-ICDP Workshop examines challenges of fault zone drilling" Scientific Drilling 1 p5-16

Bleibinhaus, Florian, Hole, John A., Ryberg, Trond, Fuis, Gary S. (2007). "Structure of the California Coast Ranges and San Andreas Fault at SAFOD from seismic waveform inversion and reflection imaging" Journal of Geophysical Research: Solid Earth 112 pB06315

Chavarria, J. Andres, Goertz, Alex, Karrenbach, Martin, Paulsson, Bjorn, Milligan, Paul, Soutyrine, Vlad, Hardin, Alan, Dushman, David, LaFlame, Lisa (2007). "The use of VSP techniques for fault zone characterization: An example from the San Andreas Fault. " The Leading Egde 26 p770-776

Solum, John G., Hickman, Stephen H., Lockner, David A., Moore, Diane E., van der Pluijm, Ben A., Schleicher, Anja M., Evans, James P. (2006). "Mineralogical characterization of protolith and fault rocks from the SAFOD Main Hole" Geophysical Research Letters 33 pL21314

Prevedel, B., Kück, J. (2006). "New Developments in Long-Term Downhole Monitoring Arrays" Sci. Dril. 2 p34-36

Schleicher, Anja M., van der Pluijm, Ben A., Solum, John G., Warr, Laurence N. (2006). "Origin and significance of clay-coated fractures in mudrock fragments of the SAFOD borehole (Parkfield, California)" Geophysical Research Letters 33 pn/a-n/a

Erzinger, J., Wiersberg, T., Zimmer, M. (2006). "Real-time mud gas logging and sampling during drilling" Geofluids 6 p225-233

Hole, J. A., Ryberg, T., Fuis, G. S., Bleibinhaus, F., Sharma, A. K. (2006). "Structure of the San Andreas fault zone at SAFOD from a seismic refraction survey" Geophysical Research Letters 33 pL07312

Erzinger, Jörg, Wiersberg, Thomas, Dahms, Eckhard (2004). "Real-time mud gas logging during drilling of the SAFOD Pilot Hole in Parkfield, CA" Geophysical Research Letters 31

Fuis, GS, Ryberg, T, Godfrey, NJ, Okaya, DA, Murphy, JM (2001). "Crustal structure and tectonics from the Los Angeles basin to the Mojave Desert, southern California" Geology 29 (1) p15-18

Fuis, G. S., Ryberg, T., Lutter, W. J., Ehlig, P. L. (2001). "Seismic mapping of shallow fault zones in the San Gabriel Mountains from the Los Angeles Region Seismic Experiment, southern California" Journal of Geophysical Research: Solid Earth 106 p6549-6568

Ryberg, Trond, Fuis, Gary S. (1998). "The San Gabriel Mountains bright reflective zone: possible evidence of young mid-crustal thrust faulting in southern California" Tectonophysics 286 p31-46