Simulations still can’t predict exactly when an earthquake will happen, but with the incredible processing power of modern exascale supercomputers, they can now predict how they will happen and how much damage they will likely cause.
Simulations still can’t predict exactly when an earthquake will happen, but with the incredible processing power of modern exascale supercomputers, they can now predict how they will happen and how much damage they will likely cause.
Imagine a colossal earthquake striking the California coast along the San Andreas Fault, one of the world’s most active areas of seismic activity. Scientists have long been predicting this so-called « Big One. » But instead of chaos, there’s calm, thanks in part to an advanced early warning system that gave plenty of notice for people to take cover inside specially engineered, quake-resistant structures.
It’s a potential future that David McCallen, a senior research scientist at Lawrence Berkeley National Laboratory, is working to make a reality—one in which earthquakes are met with preparedness, not panic.
McCallen is leading a team of researchers from Berkeley and Oak Ridge national laboratories in a project to develop the most innovative and advanced simulations to date for studying earthquake dynamics.
The simulations reveal in stunning new detail how geological conditions influence earthquake intensity, and in turn, how those complex ground motions directly impact buildings and infrastructure. The data is already being shared with the broader earthquake science and engineering communities to deepen the understanding of seismic behavior and to guide the designs of earthquake-resistant infrastructure and improve emergency response.
« Our goal is to model earthquakes from beginning to end and track the seismic waves as they propagate through Earth », said McCallen, who also leads the Critical Infrastructure Initiative at Berkeley Lab. « We want to understand how those waves interact with buildings and critical energy infrastructure to assess their vulnerability so they can be as prepared as possible before the next earthquake strikes. »
The research began in 2017 as part of the Exascale Computing Project (ECP), DOE’s largest-ever software research, development and deployment initiative. The project charged experts with designing applications and solutions for complex scientific problems that were impossible to solve with the computing capabilities that existed prior to ECP.
Traditional earthquake simulations have relied on rough estimates based on data from past events to study earthquake ground motions. However, until now, scientists have lacked the computational power to model earthquakes in specific locations with sufficient fidelity.
From the ECP, McCallen and his team developed EQSIM, the Earthquake Simulation code. EQSIM allows researchers to see how seismic waves interact with different soil compositions and surface topologies such as mountains and valleys that can either amplify or dampen an earthquake’s energy and momentum. The ground motion simulations can then be applied to buildings and critical infrastructure, such as water and electric utilities providers, to see how those structures will respond to seismic activity and where they are likely to fail.
« We’ve advanced the ability to do these computations tremendously », McCallen said. « Instead of using empirical data from past events like we’ve had to do up to this point, the exascale simulations are allowing us to develop a much better picture of what these regional distributions of ground motions look like.
« This is something we’ve not been able to see before, and what we’re seeing is that ground motion behavior is far more complex and dynamic than we thought. »
What most people might find surprising is that in some cases, smaller earthquakes can actually cause more damage than larger ones—it all depends on the underlying geological conditions, McCallen says.
The intense shaking during an earthquake, known as ground motion, is shaped by three key geological factors: 1) fault type—how tectonic plates shift against each other and the manner in which an earthquake fault ruptures; 2) rock and soil composition—whether the ground is solid or fractured, hard or soft; and 3) surface topography—including mountains, valleys and even buildings. All these factors influence the strength and behavior of seismic waves.
