SCEC Award Number 19104 View PDF
Proposal Category Collaborative Proposal (Data Gathering and Products)
Proposal Title Developing a Geologic Framework Model and Enhancements to the CVM in the Unified Structural Representation Framework
Name Organization
John Shaw Harvard University Thomas Jordan University of Southern California
Other Participants Andreas Plesch
SCEC Priorities 3b, 4a, 4c SCEC Groups Seismology, CXM
Report Due Date 04/30/2020 Date Report Submitted 06/15/2020
Project Abstract
We developed an initial version of the SCEC Geologic Framework Model (GFM) that describes crust and upper mantle structure in Southern California. The model consists of crust, upper mantle and asthenosphere layers with the crustal layer being subdivided into 23 lithotectonic units. The model grid houses cells parametrized with a region number linked to a name and lithology type, as well as temperature with placeholders for a variety of other geophysical properties. The GFM is intended to support SCEC efforts to develop a Community Rheology Model (CRM) and support a range of other science activities.

We also applied a k-means algorithm to the SCEC Community Velocity Models (CVMs) to define various regionalizations that we compared with geologic and other geophysical constraints on structure of the crust. This analysis suggests robust, low-order regionalizations are geologically valid for both versions of the SCEC CVM’s (CVM-S 4.26 and CVM-H 15.1), while higher order regionalizations for the CVM-S show greater consistency with more detailed aspects of inferred crustal composition (see Eymold & Jordan, 2019). The analysis highlighted deficiencies in the models, as well as identified ways that the method may be used to improve future iterations of the Geologic Framework Model (GFM).
Intellectual Merit This project is the primary effort to develop a Geologic Framework Model (GFM), which is central to develop the Community Rheologic Model (CRM) and a range of other models that support SCEC science objectives.
Broader Impacts The project promotes training of graduate students, and ultimately will improve SCEC's ability to assess seismic hazard in Southern California, with the goal of helping to mitigate risk. We also develop and apply new methods for generating structural models to support earthquake science that can be applied to other areas in the United States and throughout the world.
Exemplary Figure Figure 1: Left: Perspective view of Southern California with GFM unit boundaries (yellow) and horizons (color contoured Moho and reflective LAB). Black outlines show CFM faults corresponding to unit boundaries. Right: Identical perspective view of GFM grid showing crustal, lithotectonic units (regions of color scale), the upper mantle layer (dotted), and the asthenosphere layer (solid green). Three crustal units are dotted to provide a sense of the volumetric nature of the grid. 3x vertical exaggeration.