2026 SCEC Parkfield 2.0 Workshop

Date: June 10-11, 2026
Location: NASA Silicon Valley Event Center, Moffett Field, CA
Workshop Organizers: Bill Ellsworth (Stanford), Roland Burgmann (UC Berkeley), Cliff Thurber (UW Madison), Yihe Huang (UM Ann Arbor), Andy Barbour (USGS), Nathan Toke (Utah Valley)
SCEC Award: 26052

Summary

The Parkfield region along the San Andreas Fault remains one of the world’s premier natural laboratories for earthquake science. With its long history of repeating magnitude 6 earthquakes, decades of extensive geophysical and geological observations, and the San Andreas Fault Observatory at Depth (SAFOD), Parkfield provides unique opportunities to investigate fault behavior, fault-zone structure, earthquake nucleation, rupture propagation, and the underlying physics of the earthquake cycle. The region also exhibits the full spectrum of fault slip behavior—including earthquakes, creep, tremor, slow slip, and repeating earthquakes—making it an exceptional location for developing and testing new observational, experimental, and computational approaches.

Building on this scientific foundation, the goal of the 2026 SCEC Parkfield 2.0 Workshop was to develop a shared vision for the next generation of Parkfield research. The workshop brought together observational geoscientists, geodesists, seismologists, laboratory researchers, and numerical modelers to review decades of scientific discoveries, assess emerging observational and computational capabilities, and identify the critical scientific questions, infrastructure investments, and coordinated community activities needed to advance Parkfield as a next-generation earthquake observatory.

Invited presentations reviewed the history of the Parkfield Earthquake Prediction Experiment, advances in fault-zone imaging, geology, geodesy, laboratory studies, earthquake-cycle modeling, and the evolving role of SAFOD. Panel discussions and six interdisciplinary breakout groups then identified priorities for Parkfield 2.0, emphasizing modernization of the Parkfield Observatory, improved operational readiness, integrated observations and physics-based models, and strengthened interdisciplinary collaboration. Together, these discussions established a community roadmap for future Parkfield research aligned with the SCEC Science Plan.

The 2026 SCEC Parkfield 2.0 Workshop convened 110 participants to define a shared vision for the future of Parkfield research. Over two days, invited presentations, panel discussions, poster sessions, and interdisciplinary breakout groups identified scientific priorities, infrastructure investments, and coordinated community activities needed to advance Parkfield as a next-generation earthquake observatory. SEE PHOTOS

Key Outcomes

The workshop presentations, panel discussion, and breakout sessions established a shared vision for Parkfield 2.0 and identified scientific priorities, infrastructure needs, and coordinated community activities to guide the next generation of Parkfield research. Highlights are summarized below, with additional detail available in the workshop report and the breakout session summaries.

Developed a shared vision for Parkfield 2.0: Participants concluded that Parkfield remains uniquely positioned to address fundamental questions about earthquake nucleation, rupture propagation, fault-zone processes, and earthquake cycles. The workshop articulated a vision for evolving Parkfield from the original earthquake prediction experiment into a next-generation community observatory integrating long-term observations, physics-based modeling, laboratory experiments, and emerging computational methods. Participants also emphasized using Parkfield to develop and test approaches applicable to more complex fault systems worldwide.
Identified priorities for modernizing the Parkfield Observatory: The workshop identified modernization of the Parkfield Observatory as a critical step toward addressing future scientific objectives. Breakout discussions recommended leveraging existing infrastructure while expanding observational capabilities through next-generation seismic, geodetic, and fiber-optic sensing technologies, improved telemetry, and complementary instrument networks designed around specific scientific hypotheses. Participants emphasized integrating multiple observational techniques to better characterize fault-zone processes across spatial and temporal scales while providing a flexible testbed for evaluating emerging monitoring technologies.
Established a coordinated framework for operational readiness: Recognizing that the next Parkfield earthquake represents a rare scientific opportunity, participants developed priorities for improving operational readiness before the next significant event occurs. Recommendations included coordinated response plans, clearly defined organizational roles, instrumentation deployment strategies, mechanisms for real-time data coordination, engagement with local landowners and agencies, and expanded community outreach. Participants emphasized that advance planning would maximize the scientific value of future earthquake observations while improving collaboration among government, academic, and industry partners.
Identified priority scientific questions for Parkfield 2.0: Workshop discussions identified several priority scientific challenges that should guide future research at Parkfield. These include understanding earthquake nucleation and rupture processes, interactions between creeping and locked sections of the San Andreas Fault, the role of fault-zone heterogeneity in rupture propagation and arrest, the relationship between repeating earthquakes, tremor, creep, and earthquake cycles, and the connections between Parkfield earthquakes and future 1857-type ruptures. Participants emphasized that resolving these questions will require integrating geology, geodesy, seismology, laboratory studies, and physics-based earthquake simulations within a coordinated research framework.
Strengthened community coordination for future Parkfield research: The workshop concluded with six interdisciplinary breakout groups that synthesized presentations and discussions into community recommendations for observatory modernization, operational readiness, fault-zone monitoring, earthquake-cycle investigations, and the long-term Parkfield 2.0 vision. The report-back discussions reinforced the importance of sustained collaboration among observational scientists, modelers, laboratory researchers, engineers, and students to coordinate future Parkfield research.

References

Ellsworth, W. L., Bürgmann, R., Thurber, C. H., Huang, Y., Barbour, A. J., & Toke, N. A. (2026). 2026 SCEC Parkfield 2.0 Workshop Report: Statewide California Earthquake Center. SCEC Contribution 15246
William H. Bakun; Memories of the Parkfield Earthquake Prediction Experiment. Seismological Research Letters 2026; doi: https://doi.org/10.1785/0220260131

All times below Pacific Standard Time (UTC -7)

Presentation materials may be viewed by clicking the links below. PLEASE NOTE: Files are the author’s property. They may contain unpublished or preliminary information and should only be used for reviewing the talk. Only the presentations for which SCEC has received permission to post publicly are included below.

Wednesday, June 10, 2026

Time	Agenda Item	Presenter
10:00 - 12:00	Session 1: Introduction to Parkfield and State of Knowledge The opening session set the stage for the workshop by reviewing the history of Parkfield earthquake research, its role as a natural laboratory on the San Andreas Fault, and the current state of scientific understanding. The session featured four invited talks followed by an interactive panel discussion that framed key questions and opportunities for the workshop. Session Chair: Bill Ellsworth
10:00 - 10:15	Introduction	Bill Ellsworth
10:15 - 10:30	Parkfield V1.0: 1985-2004	John Langbein
10:30 - 10:45	Geodetic imaging of earthquake cycles at Parkfield (PDF)	Jessica Murray
10:45 - 11:00	Geophysical Insights into the 3D Structure of the Parkfield Region (PDF)	Cliff Thurber
11:00 - 11:15	USGS Instrumentation and Observation Activity at Parkfield: Current Status (PDF)	Liz Hearn
11:15 - 12:00	Discussion
12:00 - 13:00	Lunch & Poster Session 1 An informal poster session provided an opportunity for participants to share and explore a broad range of past, ongoing, and future Parkfield‑related research.
13:00 - 14:30	Session 2: Geology and SAFOD Legacy This session focused on San Andreas Fault geology and structure, spanning the creeping central fault, Parkfield segment and the 1857 rupture. This session also explored insights gained from the San Andreas Fault Observatory at Depth (SAFOD). Five short talks were followed by a moderated discussion on unresolved questions and future directions. Session Chair: Andy Barbour
13:00 - 13:15	Attempts to discriminate between paleoseismic evidence of creep and paleoseismic ruptures along the central San Andreas fault (PDF)	Nathan Toke
13:15 - 13:30	Do earthquakes rupture through the creeping section of the San Andreas Fault? Evidence from geology	Belle Philibosian
13:30 - 13:45	SAFOD: Lessons Learned, Current Status and Future Possibilities (PDF)	Steve Hickman
13:45 - 14:00	"Parkfield in the lab" what has/can rock mechanics do to address Parkfield’s driving questions	Sara Beth Cebry
14:00 - 14:30	Discussion
14:30 - 15:00	Break & Poster Session 2 A poster session highlighted additional contributions and continued discussion in an informal setting.
15:00 - 16:30	Session 3: Parkfield Earthquakes and Fault Behavior This session examined the full spectrum of fault behavior on display near Parkfield where the central creeping section of the San Andreas fault meets the locked sections of the fault to the south. Since the dawn and sunrise foreshocks leading up to the Great 1857 earthquake there have been five ~M6 events, creep increases from zero to more than 25 mm/a in just over 30 km, and geophysical monitoring has enabled the observation of fascinating patterns of microseismicity and slow slip events. Talks covered observational, theoretical, and modeling perspectives with discussion centered on what the diverse patterns of slip behavior teach us about how faults work over various timescales. Session Chair: Yihe Huang
15:00 - 15:15	Tremor and Low-Frequency Earthquakes at Parkfield: A window into the lower-crustal San Andreas Fault	David Shelly
15:15 - 15:30	Fault creep, surface rupture, and aftership near Parkfield California: past and current phenomena and future possibilities	Steve DeLong
15:30 - 15:45	Revisiting Parkfield Mainshocks: A characteristic Snowflake Model	Sue Hough
15:45 - 16:00	Strong Ground Motion Observations from the CSMIP Parkfield Array: 2004 Data, Comparisons, and Network Evolution	Hamid Haddadi
16:00 - 16:30	Discussion
16:30 - 17:00	Lightning Talks A fast‑paced session highlighted emerging ideas, new datasets, and novel approaches from across the community. Lightning talks were designed to spark discussion, seed collaborations, and showcase perspectives from both established and newer Parkfield researchers. (PDF) Session Chair: Cliff Thurber
17:00 - 18:30	Dinner & Breakout Session 1: Identifying Grand Challenges Small‑group discussions focused on synthesizing ideas from Day 1 and identifying major scientific challenges and opportunities for Parkfield research. Breakouts emphasize interdisciplinary perspectives and community‑driven prioritization.

Thursday, June 11, 2026

Time	Agenda Item	Presenter
07:00 - 08:30	Breakfast & Poster Session 2 A second poster session highlighted additional contributions and continued discussion in an informal setting.
08:30 - 10:00	Session 4: Geodesy and Earthquake Cycles This session explored geodetic observations and models of the earthquake cycle at Parkfield, from interseismic deformation to coseismic and postseismic processes. Presentations and discussion focused on linking surface observations to fault‑zone processes at depth. Session Chair: Nathan Toke
08:30 - 08:45	Numerical Modeling of Parkfield Repeating Earthquakes: Stress Drops, Synchronization, and Aseismic Slip (PDF)	Semechah Lui
08:45 - 09:00	Parkfield earthquakes: lessons from geodesy (PDF)	Yuri Fialko
09:00 - 09:15	Simulating and observing earthquake cycles through off-fault deformation	Yihe Huang
09:15 - 09:30	How are interseismic, co-seismic, and post-seismic observations of Mw 6 Parkfield related to each other? Insights from physics-based modeling and questions to the future event(s)	Nadia Lapusta
09:30 - 10:00	Discussion
10:00 - 10:30	Poster Session 3 (and coffee/tea hosted by SCEC) Final opportunity to view posters and engage in informal scientific discussions.
10:30 - 12:00	Session 5: Critical Research Needs and Opportunities A forward‑looking session focused on identifying critical research gaps, emerging tools, and opportunities for coordinated community efforts. Talks and discussion emphasized alignment with national priorities and pathways for future collaborative activities centered on Parkfield. (PDF) Moderator: Roland Bürgmann Invited Panelists: Tim Dawson, Kim Blisniuk, Elizabeth Cochran, Ahmed Elbanna, Allison Faris
12:00 - 13:00	Lunch
13:00 - 14:30	Breakout Session 2: Developing Community Reports Participants worked in breakout groups to synthesize discussions into concise reports outlining key scientific questions, priorities, and recommended community actions.
14:30 - 15:00	Break
15:00 - 16:30	Session 6: Report‑Back and Wrap‑Up Discussion Breakout groups presented their findings, followed by a group discussion to integrate results into a shared vision for the future of Parkfield science.
16:30	Workshop adjourns
16:30 - 17:00	Meeting of the Workshop Organizing Committee

Poster Presentations

The workshop featured 18 poster presentations spanning geology, geodesy, seismology, earthquake-cycle modeling, SAFOD investigations, and next-generation monitoring technologies. Complementing the invited presentations, the poster sessions highlighted both established and emerging Parkfield research while fostering discussion and collaboration across the communities shaping the Parkfield 2.0 vision.

#	Last Name	First Name	Poster Title
3	Aguilar Suarez	Leonardo	Enhanced Earthquake Catalog for Parkfield
5	Blanpied	Michael	The NEHRP Post-Earthquake Investigations Program
8	Clements	Tim	The need for (more) continuous acceleration data in Parkfield, CA
14	Fang	Lihua	Trade space for time for inspecting an earthquake cycle by modern seismological observation: The central-southern part of the Sichuan-Yunnan rhombic block
13	Gong	Jianhua	A Tale of Two Faults: Comparing Long-Term Seismicity Patterns Along the Parkfield and Gofar Transform Faults
1	Harris	Ruth	Four decades of Parkfield Science Discoveries
10	Li	Linxuan	Ubiquitous Interactions and Subcritical Patches Explain the Irregularity of Repeating Earthquakes
15	Lin	Li-Chieh	The Full Kinematics of the Central San Andreas Fault using UAVSAR and Sentinel-1 data
4	Margolis	Adam	An Updated San Andreas Fault Geometry in Parkfield, California
18	Arrowsmith	Ramon	Middle Mountain Geologic Structure and 2004 Earthquake Surface Fracturing
17	Peng	Zhigang	Re-estimating the early aftershock decay rate and the aftershock duration of the 2004 M6.0 Parkfield earthquake
16	Moore	Diane	Deformation history of cataclasite recovered in SAFOD core adjacent to the SDZ
9	Shrestha	Rajani	Linear Streaks of Seismicity Along the San Andreas
12	Sun	Yudong	Experimental and Numerical Modeling of Earthquake Rupture Interactions Across Multiple Asperities and Barriers
6	Yoon	Clara	Preparing a rapid enhanced aftershock catalog workflow for the next Parkfield earthquake
7	Zhang	Hao	Imaging the rupture of next Parkfield earthquakes with Distributed Acoustic Sensing
11	Zhang	Wenqiang	Adjoint-based inversion for stress and frictional parameters in 3D dynamic earthquake rupture models
2	Alongi	Travis	Fault zone complexity and roughness measured with seismicity at Parkfield

Participants

The workshop brought together 110 participants from universities, government agencies, and national laboratories in the United States and abroad, representing expertise in geology, geodesy, seismology, geophysics, rock mechanics, numerical modeling, and earthquake engineering. This broad interdisciplinary participation supported the development of a shared vision for Parkfield 2.0, fostered collaboration across observational and modeling communities, and helped identify coordinated priorities for future Parkfield research.

Last Name	First Name	Organization
Aguilar Suarez	Leonardo	Stanford University
Alongi	Travis	U.S. Geological Survey
Ampuero	Jean-Paul	Université Côte d'Azur
Arrowsmith	Ramon	Arizona State University
Atterholt	James	U.S. Geological Survey
Baden	Curtis	U.S. Geological Survey
Bakun	William	U.S. Geological Survey (Retired)
Baltay	Annemarie	U.S. Geological Survey
Barall	Michael	U.S. Geological Survey
Barbour	Andy	U.S. Geological Survey
Belyalova	Alina	Stanford University
Bilham	Roger	University of Colorado
Biondi	Ettore	Stanford University
Blanpied	Michael	U.S. Geological Survey
Blisniuk	Kim	San Jose State University
Bolton	Chas	University of Texas at Austin
Branum	David	California Geological Survey
Burgmann	Roland	University of California, Berkeley
Can	Birsen
Carpenter	Brett	University of Oklahoma
Castillo	Emmanuel
Catchings	Rufus	U.S. Geological Survey
Cebry	Sara	U.S. Geological Survey
Clements	Timothy	U.S. Geological Survey
Cochran	Elizabeth	U.S. Geological Survey
Croker	Dave	U.S. Geological Survey
D'Agostino	Nicola	Istituto Nazionale di Geofisica e Vulcanologia
Danré	Philippe	Ecole Normale Supérieure
Davis	Karen	U.S. Geological Survey
Dawson	Tim	California Geological Survey
DeLong	Stephen	U.S. Geological Survey
Delorey	Andrew	Los Alamos National Laboratory
Elbanna	Ahmed	USC/SCEC
Ellsworth	Bill	Stanford University
Fang	Lihua	China Earthquake Administration
Faris	Allison	U.S. Geological Survey
Fialko	Yuri	University of California, San Diego
Funning	Gareth	University of California, Riverside
Gallovic	Frantisek	Charles University, Prague
Gong	Jianhua	Indiana University
Guns	Katherine	U.S. Geological Survey
Guo	Hao	University of Wisconsin-Madison
Guoxu	Chen	University of Wisconsin-Madison
Haddadi	Hamid	California Geological Survey
Hagos	Lijam	California Geological Survey
Hanagan	Catherine (Cassie)	U.S. Geological Survey
Hardebeck	Jeanne	U.S. Geological Survey
Harris	Ruth	U.S. Geological Survey
Hearn	Elizabeth	U.S. Geological Survey
Hellweg	Peggy	University of California, Berkeley
Hill	Ryley	U.S. Geological Survey
Hough	Susan	U.S. Geological Survey
Hu	Yanlan	Stanford University
Huang	Yihe	University of Michigan
Igonin	Nadine	University of Texas at Dallas
Jeppson	Tamara	U.S. Geological Survey
Kuo	Li-Wei	National Central University
Langbein	John	U.S. Geological Survey
Lapusta	Nadia	California Institute of Technology
Li	Linxuan	California Institute of Technology
Li	Jack	California Institute of Technology
Lin	Li-Chieh	University of California, Riverside
Liu	Yajing	McGill University
Louage	Rémi	École Normale Supérieure
Lu	Weifan	Columbia University
Lui	Semechah	University of Toronto
Madden	Elizabeth	San Jose State University
Margolis	Adam	University of California, Riverside
Martínez-Garzón	Patricia	GFZ Helmholtz Centre for Geosciences
McGuire	Jeff	U.S. Geological Survey
Mei	Cheng	Columbia University
Meng	Xiaofeng	USC/SCEC
Minson	Sarah	U.S. Geological Survey
Miranda	Raul	University of California, Berkeley
Moore	Diane	U.S. Geological Survey (Retired)
Murray	Jessica	U.S. Geological Survey
Nevitt	Josie	U.S. Geological Survey
Parker	Grace	U.S. Geological Survey
Pauk	Edric	USC/SCEC
Peng	Zhigang	Georgia Tech
Perez Silva	Andrea Carolina	University of California, Berkeley
Philibosian	Belle	U.S. Geological Survey
Rademacher	Horst	Independent
Roecker	Steven	Rensselaer Polytechnic Institute (Emeritus)
Rong	Bo	University of California, Berkeley
Rubinstein	Justin	U.S. Geological Survey
Schultz	Adam	Oregon State University
Segall	Paul	Stanford University
Shelly	David	U.S. Geological Survey
Shrestha	Rajani	California Institute of Technology
Si	Xu	University of California, Berkeley
Sone	Hiroki	University of Wisconsin-Madison
Song	Junhao	University of California, Berkeley
Sun	Yudong	Stanford University
Swinscoe	Rebecca	University of California, Berkeley
Taira	Taka'aki	University of California, Berkeley
Thatcher	Wayne	U.S. Geological Survey
Thurber	Clifford	University of Wisconsin-Madison
Toke	Nathan	Utah Valley University
van der Elst	Nicholas	U.S. Geological Survey
van der Heiden	Vincent	GFZ Helmholtz Centre for Geosciences
Vargas	Javier Ojeda	Universidad Nacional Autónoma de México
Vermeer	Jessie	U.S. Geological Survey
Wang	Lei	University of Wisconsin-Madison
Wesson	Rob	U.S. Geological Survey (Retired)
Yoon	Clara	U.S. Geological Survey
Zhang	Hao	California Institute of Technology
Zhang	Wenqiang	Stanford University
Zhu	Weiqiang	University of California, Berkeley

Registration and Travel Support

The workshop was initially planned for approximately 75 participants, selected through an application process based on their statements of interest and potential contributions to the workshop objectives. Strong interest in the workshop prompted organizers to expand participation beyond the original target while maintaining a balanced representation of expertise across career stages and preserving the collaborative format of the meeting.

The workshop registration fee was $115, which covered meals and breaks listed on the June 10–11 agenda. Travel support was available to help offset travel, lodging, and/or meal expenses associated with attending the workshop. Students, early-career researchers, and participants without institutional funding were especially encouraged to request support as part of the application process.

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The Statewide California Earthquake Center (SCEC) fosters a diverse and inclusive community where everyone feels safe, productive, and welcome. We expect all participants in SCEC-supported events to uphold this commitment by adhering to the SCEC Activities Code of Conduct.

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