Key Outcomes

The workshop produced several important scientific and community outcomes that will guide future research on earthquake rupture, fault creep, and the role of shallow Earth materials in earthquake deformation and ground motions. Highlights are summarized below, with additional detail available in the workshop report.

1. A shared vision for studying shallow Earth materials across disciplines: A principal outcome of the workshop was broad community consensus on the need to build an interdisciplinary research ecosystem focused on shallow (<3 km) Earth materials. Participants recognized that understanding shallow deformation and ground motion requires closer integration of field observations, laboratory experiments, geodesy, geophysics, geochemistry, earthquake engineering, and numerical modeling. The workshop established a shared scientific framework for studying how shallow materials influence earthquake rupture, creep, and seismic site response across the earthquake cycle, while recognizing their foundational role in strengthening SCEC Community Earth Models (CEMs) and improving earthquake and seismic hazard models.
2. Priorities for future observations and monitoring: Participants identified several high-priority scientific questions requiring coordinated future observations, including the depth extent of fault creep, the role of lithology and fluids in controlling deformation, and the relationship between localized and distributed strain. Discussions highlighted the need for sustained monitoring infrastructure, improved characterization of shallow material properties, and expanded use of emerging technologies such as distributed acoustic sensing (DAS), optical image correlation, LiDAR, and other high-resolution geodetic and geophysical observations. The workshop also emphasized preserving and expanding long-term observational capabilities, including creepmeter networks, as essential community infrastructure.
3. Bridging earthquake science and engineering: The workshop identified important opportunities to strengthen collaboration between earthquake scientists and geotechnical engineers by connecting fault-zone observations with site response analyses and ground motion modeling. Participants emphasized that many complementary datasets already exist but are difficult to integrate because of differences in terminology, measurement scales, and modeling approaches. Developing a shared scientific vocabulary, interoperable datasets, and common frameworks for incorporating shallow Earth properties into earthquake simulations was identified as a critical step toward reducing uncertainties in seismic hazard assessments.
4. Building a collaborative Shallow Earth Materials community: The workshop brought together 37 participants, including 21 early-career scientists, for a field trip, invited presentations, and moderated discussions spanning the full spectrum of SCEC disciplines. The combination of field observations along the Southern San Andreas Fault and interdisciplinary scientific discussions created a common understanding of shallow deformation processes while fostering new collaborations among geologists, geodesists, laboratory scientists, engineers, and modelers. Post-workshop survey responses were overwhelmingly positive, with equal appreciation expressed for both the field trip and scientific discussions, and all respondents indicated interest in continued collaboration through future workshops, white papers, or community activities.
5. Establishing a roadmap for future community activities: The workshop concluded with concrete recommendations for sustaining collaboration beyond the meeting. Participants identified training opportunities, and integration with SCEC Community Earth Models (CEMs), including the Community Velocity Model (CVM) and Community Rheology Model (CRM), as priorities for future work. These discussions established the foundation for the subsequent SCEC Technical Activity Group (TAG) proposal on Shallow Earth Materials, which seeks to coordinate future research, observations, workforce development, and community engagement.

References

Griffith, W. A., Scharer, K. M., & Ault, A. K. (2026). Workshop Report: Earthquake Rupture and Creep in Shallow Earth Materials, Statewide California Earthquake Center. SCEC Contribution 15056