Ridgecrest shows how earthquakes damage Earth's crust

In July 2019, a series of earthquakes including two major shocks of magnitude 6.4 and 7.1 a day apart struck near Ridgecrest, CA, between Los Angeles and Las Vegas. For local residents, it was a violent interruption to the Fourth of July holiday. For seismologists, it was a rare opportunity to study how earthquakes damage the Earth's crust.

The earthquake zone - which belongs to a network of faults called the Eastern California Shear Zone - is sparsely populated and arid, without much in the way of vegetation or buildings to obscure the surface. But it is also well-covered by satellite and remote imagery and accessible to geologists who could be on the scene well before evidence of crust damage disappeared.

UC Davis doctoral student Alba Rodriguez Padilla was among the scientists studying the site, along with Professor Mike Oskin, Department of Earth and Planetary Sciences, Christopher Milliner, California Institute of Technology and Andreas Plesch of Harvard University. They mapped the surface rupture from LIDAR data and aerial imagery collected by prior studies, and compared the rupture maps to other datasets to explore the distribution of rock damage from the earthquakes. Their findings are published Feb. 24 in Nature Geoscience.

"We not only have aridity helping here, improvements in imaging technique and resolution, together with collecting a large spatial data footprint, are what make the Ridgecrest coverage cutting edge," Rodriguez Padilla said.

Inelastic deformation
The rock surrounding the fault suffered from "inelastic deformation," meaning it was deformed and broken rather than returning to its original configuration. The deformation was highest within 100 meters of the fault, with widespread, low-intensity damage up to 20 kilometers (16 miles) away.

This deformation leaves the rock around the fault less rigid than before, softening the crust. This softening dissipates energy from future earthquakes, increases permeability and focuses deformation.

The study provides a better understanding of how damage from earthquakes accumulates and might affect future events, Rodriguez Padilla said.

The study was funded by the Southern California Earthquake Center, which is supported by NSF and the U.S. Geological Survey. Rodriguez Padilla was partly supported by a NASA fellowship.

Research Report: "Accrual of widespread rock damage from the 2019 Ridgecrest earthquakes"

Related Links
University of California - Davis
Tectonic Science and News

Tweet

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only

SpaceDaily Contributor
$5 Billed Once

credit card or paypal

Explosive fossil fruit found buried beneath ancient Indian lava flows
Gainesville FL (SPX) Feb 18, 2022
Just before the closing scenes of the Cretaceous Period, India was a rogue subcontinent on a collision course with Asia. Before the two landmasses merged, however, India rafted over a "hot spot" within the Earth's crust, triggering one of the largest volcanic eruptions in Earth's history, which likely contributed to the extinction of the dinosaurs. In a recent study, scientists excavating the fossilized remains of plant material wedged between layers of volcanic rock describe a new plant species b ... read more