SCEC Award Number 24026 View PDF
Proposal Category Collaborative Research Project (Multiple Investigators / Institutions)
Proposal Title Constructing a multi-parameter thermal model of California to investigate thermal influences on crustal rheology and earthquake processes
Investigator(s)
Name Organization
Andrew Zuza University of Nevada, Reno Daniel Trugman University of Nevada, Reno
SCEC Milestones A2-2, B3-1 SCEC Groups CEM, Geodesy
Report Due Date 03/15/2025 Date Report Submitted 01/29/2025
Project Abstract
 The objective of this project was to develop a new multi-disciplinary crustal thermal model for California and Nevada, which directly supports the research priority of the Statewide California Earthquake Center (SCEC) to broaden the Community Thermal Model (CTM) to a statewide scale. Our thermal model incorporates available relevant temperature proxies, including surface heat flow, relocated seismicity as it relates to seismogenic thickness, and crust-mantle boundary temperature and depth estimates derived from Pn velocity models. We fit these temperature proxies with vertical 1D conductive heat transport solutions to output a 3D array of temperature information throughout the California and Nevada crust. Our 3D temperature dataset predictably shows hot crust in regions with active volcanism and/or geothermal activity (e.g., Clear Lake volcanic field, Coso, the Salton Trough), and colder areas that are seismically stable and inferred to be strong (e.g., the Sierra Nevada-Great Valley). This dataset can be queried for 2D temperature profiles and input into viscosity models. We also test for correlations between crustal temperature, heat flow, Quaternary fault density, strain rate, earthquake productivity, crustal thickness, and other parameters. This work provides a new thermal model for the community, and we recently submitted a proposal for SCEC 2025 to support the publication of this model onto the SCEC platform and to compare our model against other thermal models.
SCEC Community Models Used Community Thermal Model (CTM)
Usage Description We compared our new thermal model results to the existing CTM. Our newly developed thermal model encompasses a larger region than the old CTM, which only includes southern California.
Intellectual Merit The generation of a new thermal model for statewide California, and adjacent Nevada, provides a framework to develop 3D rheology models and test the impact of temperature on deformation and earthquake generation. The model has been developed to be fully accessible, so that other users can examine our inputs, provide alternative inputs, or model a different geographic extent.
Broader Impacts This work contributed to the broader goals of SCEC by constructing a crustal thermal model that encompasses the entire state of California. This work was led by a PhD student, whose training and growth was directly supported by this funding. Two early-mid career faculty started a new collaboration because of this support and project.
Project Participants This project involved new collaboration between UNR faculty Andrew Zuza and Daniel Trugman. This project was led by UNR PhD student Terry Lee.
Exemplary Figure Figure 1. Oblique view on the schematic block diagram of the 3D thermal model. Surface color map illustrates relative magnitude of crustal-scale geothermal gradient, while cross-section view highlights temperature distribution laterally and vertically from the surface to the Moho.
Linked Publications

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  • Lee, T., Zuza, A. V., Trugman, D. T., Vlaha, D. R., & Cao, W. (2024, 09). Multi-parameter thermal model of California and Nevada: Insights into crustal rheology and earthquake processes along the active transtensional plate boundary. Poster Presentation at 2024 SCEC Annual Meeting. SCEC Contribution Number 13823