Could California's levees fail? Engineers simulate an earthquake to find out

UCLA engineers using mobile field shakers will simulate an earthquake to test the security of the fragile system of levees in the Sacramento-San Joaquin Delta, the hub of California's water distribution system, which provides fresh water to some 23 million residents throughout the state, including Los Angeles.

Experts have projected that even a moderate earthquake in the 441,000-acre region, which lies on the eastern margin of the San Andreas fault system, could cause multiple levee failures, resulting in major flooding and an influx of saltwater from the San Francisco Bay that would halt water delivery for years, inundate farmland and sensitive wildlife habitat, and cause tens of billions of dollars in damage.

The researchers have constructed a model levee in the delta that measures 6 feet tall and 40 feet wide. (See images and video of the construction.) To conduct the full-scale earthquake testing, they will use the state-of-the-art nees@UCLA Earthquake Engineering Mobile Laboratory, which includes large shakers, actuators, instrumentation and a mobile command center. The test will measure the potential deformation of organic foundation soils that could result in a levee breach.

The resulting data on the seismic vulnerability of California's levees could help guide state and federal lawmakers in determining how to best repair and strengthen levees — both those in California, which were built in the mid-19th century, and similar levees around the world.

WHO:The following principal investigators will be available for on-site interviews:

Scott J. Brandenberg
Assistant professor of civil and environmental engineering at UCLA Engineering

Jonathan P. Stewart
Professor of civil and environmental engineering at UCLA Engineering

Robb E.S. Moss
Associate professor of civil and environmental engineering at Cal Poly College of Engineering

WHEN: 9 a.m., Monday, Aug. 29

WHERE:

The study site (represented by the green arrow on this map) is located on the interior of Sherman Island in the Sacramento-San Joaquin Delta.

Directions: Take the Sherman Island Levee Road (also called River Road) south from highway 160 and make the first right (roads are shown at the top right of the map; zoom in to see road names). A gate at the entrance is locked during off-hours but open during business hours. Follow the road until it crosses under the Antioch Bridge, and continue straight on Haul Road, on the interior of the island. The site will be on the left, about 1 mile after crossing under the Antioch Bridge.

MEDIA CONTACT:Wileen Wong Kromhout, UCLA Engineering | 310-206-0540 | wwkromhout@support.ucla.edu

Provided by UCLA