SCEC Award Number 20176 View PDF
Proposal Category Individual Proposal (Data Gathering and Products)
Proposal Title Improved LAB depth estimate: A necessary step in developing the Community Thermal Model for southern California
Name Organization
A. Christian Stanciu University of Oregon Eugene Humphreys University of Oregon
Other Participants
SCEC Priorities 1c, 3b, 3a SCEC Groups Seismology, CXM, SDOT
Report Due Date 03/15/2021 Date Report Submitted 05/03/2021
Project Abstract
Our goal is to better describe the depth of the lithosphere-asthenosphere seismic boundary beneath California to improve constraints for estimating the thermal gradients and rheology of the lithosphere as part of the development of the SCEC Community Thermal Model (CTM). Thickness of the lithosphere plays a significant role on temperature variations in the lower crust, which in turn affect rheology, lithospheric strength, and horizontal and vertical deformation partitioning. Our LAB imaging resolves high variations in the lithospheric thickness across California and adjacent regions. We image thin lithosphere beneath the Salton Trough, Inner Borderland, the San Francisco Bay area, southern end of the Great Valley, and beneath the Modoc Plateau. Thicker lithosphere is found beneath western central Nevada, western Transverse Ranges, and northern segment of the Peninsular Ranges.
Intellectual Merit The lithosphere-asthenosphere boundary (LAB) depth model contributes directly to the SCEC Community Thermal Model and represents a base for better constraints on the thermal gradients across the LAB. Accurately imaging the variations across this boundary has the potential to improve our understanding of the regional lithospheric temperature, strength and buoyancy, and ultimately the crustal faulting patterns and stress assessment.
Broader Impacts This project provided career development and research advancement opportunity for early career researcher Christian Stanciu at the University of Oregon. His work on the lithosphere-asthenosphere boundary beneath California allowed him to create a framework for mapping LAB depths that can be applied to other regions around the world, particularly areas characterized by convergent tectonics.
Exemplary Figure Figure 4. California LAB depth map. Black continuous and dotted lines indicate tectonic features and state boundaries. (2020 SCEC Report, 20176, Improved LAB estimate: A necessary step in developing the Community Thermal Model for southern California)