UC San Diego leads in the field of earthquake studies
UC San Diego's Shake Table Revolutionizing Earthquake Safety Research
UC San Diego's Englekirk Structural Engineering Center is home to a remarkable piece of technology: the world's largest outdoor earthquake simulator, known as a shake table. This advanced facility has been instrumental in pushing the boundaries of earthquake safety research and structural engineering.
The shake table, following a significant $17 million NSF-funded upgrade in April 2022, can now simulate near-real-world earthquake conditions with unprecedented accuracy. It moves in six degrees of freedom, including vertical, lateral, and rotational motions, capturing complex motions such as twisting and multi-directional shaking that were previously impossible to reproduce.
This upgrade has enabled comprehensive testing of full-scale buildings and structural components under realistic seismic loads. For instance, UC San Diego researchers have tested the tallest cold-formed steel-framed building ever examined—reaching 115 feet tall—subjecting it to simulated earthquakes of various dimensions to assess structural resilience and explore lifting regulatory height limits for cold-formed steel buildings.
The shake table's contributions extend beyond innovative building designs. It supports collaborative research with agencies like Cal Fire to investigate secondary hazards like fire following earthquakes, enhancing understanding of the compounded risks faced by occupants and first responders.
The shake table's outdoor location and its status as one of the world's largest and only outdoor seismic testing platforms further contribute to its unique role in advancing earthquake engineering.
Elsewhere, research teams from Scripps made trips to Ridgecrest, Calif., in the aftermath of the magnitude 6.4 and 7.1 earthquakes to deploy sensors and look for surface ruptures. Meanwhile, Project IDA, a network of broadband seismometers spread across every continent on Earth, provided data that determined a September 2017 event in North Korea was an explosion rather than an earthquake.
Postdoctoral Scholar Xiaohua Xu and geophysics professor David Sandwell, using GPS receivers, found dramatic vertical offsets, or major shifts in the ground, in the Ridgecrest area, potentially advancing the clock for the next earthquake. The California Real Time Network (CRTN), a network of 584 GPS stations, provided accurate geospatial information throughout California, including instant data on where the most movement, or displacement of ground, occurred in the immediate aftermath of an earthquake.
In addition, the CRTN data is vital for earthquake early warning systems, with the goal being to detect large earthquakes within 1-2 minutes before the severe shaking is felt. The technique called seismogeodesy, which relies on a combination of the GPS and seismic sensors, is used to very rapidly pinpoint the location and magnitude of strong earthquakes.
At the Geisel Library on campus, researchers are using drones, LIDAR, and GPS to create high-resolution baseline data of the structure for quick analysis of damage after an earthquake or other extreme event.
In conclusion, UC San Diego's shake table is a cutting-edge research tool that has significantly advanced earthquake safety science by enabling realistic, multidirectional seismic testing of innovative building designs and materials. Its contributions include pushing forward building code knowledge, improving post-earthquake hazard understanding, and supporting safer structural engineering practices for earthquake-prone regions.
Science and technology are integral to UC San Diego's efforts in earthquake safety research, as the school's Englekirk Structural Engineering Center houses the world's largest outdoor earthquake simulator, or shake table, which uses advanced technology to simulate near-real-world earthquake conditions. This technology has facilitated research in various fields, such as structural engineering and seismogeodesy, a technique that combines GPS and seismic sensors to rapidly pinpoint the location and magnitude of strong earthquakes.
