By Kimberly Mann Bruch
Junfei Huang, a graduate student in the Civil and Environmental Engineering Department at the University of Nevada, Reno, has been using a framework called EarthQuake SIMulation (EQSIM) to study seismic risk assessments for critical infrastructure. Huang, who works as a student assistant at the Lawrence Berkeley National Laboratory, said that he focuses his work on the evaluation of traditional engineering site response analysis.
“I am employing large-scale 3D ground motion simulations to inform corresponding implications for seismic risk assessments of critical infrastructures,” Huang said. “Historically, strong assumptions on the propagating seismic wavefield have been made in site response evaluations due to scarcity of recorded ground motion data and computational limitations.”
“With the unprecedented simulation capability realized by the EQSIM fault-to-structure framework, I am able to obtain high-fidelity 3D simulated ground motion data at any location in the regional-scale domain and am considering site-to-site variabilities of the 3D vs 1D site response comparison — all of which cannot be done with limited recorded data from real earthquake events,” Huang said. “My involvement with the development and utilization of the EQSIM framework has been one of my most fulfilling learning experiences of my Ph.D. experience and it has played a critical role in advancing my understanding in the 3D seismic wave propagation mechanism and seismic hazard imposed on civil infrastructures on a regional scale.”
The EQSIM team created an end-to-end capability to simulate from the initiation of fault rupture to site-specific ground motions and ultimately to infrastructure response. Rupture simulation for an M7 Hayward fault event shows strong ground motions (left) and resulting time synched evolution of building damage for a representative 12-story concrete building (right). Hotter colors indicate larger ground motion and major building damage, respectively. Note the complex distribution of building damage.
What Exactly is the EQSIM?
Over the past five years an integrated, multidisciplinary team from Lawrence Berkeley National Laboratory and Lawrence Livermore National Laboratory has worked to develop the EQSIM framework for fault-to-structure, regional-scale earthquake simulations under the U.S. Department of Energy Exascale Computing Project. The EQSIM application development project team has been focused on creating a computational tool set and workflow for earthquake hazard and risk assessment as used by Huang’s work.
“Our goal with EQSIM is to remove computational limitations as a barrier to simulation-based scientific exploration so that we can better understand earthquake phenomenology as well as conduct practical earthquake hazard and risk assessments,” said David McCallen, Critical Infrastructure Program Leader and researcher with the Lawrence Berkeley National Laboratory. “We’ve been using a code called SW4 along with the Department of Energy’s GPU-accelerated exaflop Frontier supercomputer to expand frequency resolution and speed of regional scale simulations.”
Details about the work can be found at https://geodynamics.org/highlight-november2023 and the SW4 code is currently available through Computational Infrastructure for Geodynamics.