A geology and geodesy based model of dynamic earthquake rupture on the Rodgers Creek‐Hayward‐Calaveras Fault System, California

Ruth A. Harris; Michael Barall; David A. Lockner; Diane E. Moore; David A. Ponce; Russell W. Graymer; Gareth J. Funning; Carolyn A. Morrow; Christodoulos Kyriakopoulos; Donna Eberhart-Phillips

doi:10.1029/2020jb020577

USGS · 70218838

A geology and geodesy based model of dynamic earthquake rupture on the Rodgers Creek‐Hayward‐Calaveras Fault System, California

Ruth A. Harris·Michael Barall·David A. Lockner·Diane E. Moore·David A. Ponce·Russell W. Graymer·Gareth J. Funning·Carolyn A. Morrow·Christodoulos Kyriakopoulos·Donna Eberhart-Phillips

View original source ↗Export metadata ↓

Abstract

The Hayward fault in California's San Francisco Bay area produces large earthquakes, with the last occurring in 1868. We examine how physics‐based dynamic rupture modeling can be used to numerically simulate large earthquakes on not only the Hayward fault, but also its connected companions to the north and south, the Rodgers Creek and Calaveras faults. Equipped with a wealth of images of this fault system, including those of its 3D geology and 3D geometry, in addition to inferences about its interseismic creep‐rate pattern and rock‐friction behavior, we use a finite‐element computer code to perform 3D dynamic earthquake rupture simulations. We find that the rock properties affect the locations and amount of slip produced in our simulated large earthquakes. Crucial factors that control rupture behavior in our modeling are the earthquake nucleation locations, the fault geometry, and the data that reveal where the fault system is creeping or locked. Our findings suggest that large Rodgers Creek‐Hayward‐Calaveras‐Northern Calaveras (RC‐H‐C‐NC) fault‐system earthquakes may result from dynamic rupture that starts in a locked part of the fault system, but is then stopped by the creeping parts, leading to high‐magnitude‐6 earthquakes; or, from dynamic rupture that starts in a locked part of the fault system, then cascades through some of the creeping parts, leading to magnitude‐7 earthquakes.

Explore related subjects

JGR Solid Earth Article

Source-reported bounding extent: 37.18657859524883° to 38.38472766885085° latitude; -122.98095703125° to -121.77246093750001° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Ruth A. Harris, Michael Barall, David A. Lockner, Diane E. Moore, David A. Ponce, Russell W. Graymer, Gareth J. Funning, Carolyn A. Morrow, Christodoulos Kyriakopoulos, Donna Eberhart-Phillips. 2021-03-16. A geology and geodesy based model of dynamic earthquake rupture on the Rodgers Creek‐Hayward‐Calaveras Fault System, California. https://doi.org/10.1029/2020jb020577

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

3D displacement from shaded relief feature offsets: Multi-decadal deceleration and secondary mini-sliding at the Slumgullion Landslide, Colorado, USA

The Slumgullion landslide in Colorado, USA, is a well-known natural laboratory for studying mass-wasting processes, owing to its ∼4 km length and sustained movement averaging a couple of centimeters per day over the past ∼300 years. However, key questions remain about how its margins and internal boundaries evolve, whether the headscarp still supplies material, and whether motion is accelerating or slowing over decadal timescales. Here we conducted offset tracking on light detection and ranging (LiDAR)-derived shaded relief images to resolve three-dimensional landslide displacements, revealing previously unrecognized secondary mini-slides close to Slumgullion's margins. Comparing our results to those from previous displacement studies revealed the landslide's long-term deceleration of motion since 1939. The secondary failures near the landslide margins and at the headscarp confirm continued material supply to the active slide. The Slumgullion landslide remains structurally dynamic with the maximum shear strain rates at ~1 yr −1 . Despite this activity, toe advance has decelerated by ∼36% since the 1990s. The approach provides a transferable framework for mapping three-dimensional deformation using high-resolution shaded relief images for landslides and other geohazards.

Colorado↗

USGS2026

Fully contained laboratory earthquakes: The effect of asperity aspect ratio and free surfaces

Corner frequency ( f c ) and seismic moment ( M 0 ) are key parameters derived from seismic signals that are used to characterize earthquake stress drop, rupture area, and slip. These parameters are also affected by fault geometry and boundary conditions. However, the systematic study of these effects in laboratory settings has been challenging. This study presents laboratory earthquake experiments that examine how rupture dynamics are influenced by (a) the aspect ratio of rectangular PMMA velocity-weakening (VW) asperities surrounded by the Teflon velocity-strengthening (VS) patches, and (b) whether the sides of a VW asperity are confined with VS patches or are free surfaces. We found that increasing confinement by reducing free surfaces or increasing the VW asperity aspect ratio stabilizes fault slip, so that higher normal stress is required to transition from aseismic to seismic slip. Increased confinement and high aspect ratios also reduced M 0 and increased f c , both of which were determined from the radiated seismic waves. M 0 and f c were primarily controlled by the shorter dimension of the VW asperity. Analysis of high-frequency acoustic emission signals revealed that ruptures on high-aspect-ratio VW asperities propagated more unidirectionally, whereas ruptures on square VW asperities were more complex. Further, the high-aspect-ratio asperities were more likely to be eroded by surrounding VS regions while low-aspect-ratio asperities were more likely to rupture into the VS surroundings. These results demonstrate that both the confinement from surrounding stable areas and the geometry of the seismogenic patch can affect rupture nucleation, propagation, and seismic source characteristics.

JGR Solid Earth↗

USGS2026

Tectonic controls on volcanism and associated hydrothermal activity in a sediment-dominated mid-ocean ridge; Escanaba Trough

Mid-ocean ridges, the Earth's most extensive volcanic system, exhibit unique characteristics in sediment-dominant environments. Thick sediment cover insulates the crust and channels fluid along pathways that can lead to the formation of distinct crustal alteration patterns, exceptionally large mineral deposits, and specialized chemosynthetic ecosystems. This study presents an interdisciplinary investigation into the tectonics of the Escanaba Trough, a heavily sedimented axial valley at the southern Gorda Ridge in the Northeast Pacific Ocean. A primary challenge in such environments is overcoming the masking effect of thick sediments on basement structures that control magmatic and hydrothermal activity. We address this by employing three-dimensional (3D) magnetic modeling of high-resolution near-seafloor magnetic data collected by an autonomous underwater vehicle (AUV). The 2022 surveys with AUV Sentry provided data for 3D magnetic susceptibility models, refining our understanding of the geometry of sub-sediment laccoliths/saucer-shaped sills and hydrothermal alteration. In conjunction with a new 1:100,000 scale lithostratigraphic map, we outline the tectonic controls on the emplacement of Escanaba Trough's three main volcanic centers, characterize the geometry of its spreading segments, and provide volumetric data on the distribution of sub-sediment volcanism in the southern Gorda Ridge.

Escanaba Trough, Pacific Ocean↗