February 8, 2024 — Scientists at the Statewide California Earthquake Center, also known as SCEC, are uncovering the enigmas of earthquakes by utilizing physics-based computational models operating on high-performance computing systems at the Department of Energy’s Oak Ridge National Laboratory. The team’s discoveries will offer a superior comprehension of seismic risks in the Golden State.
Expanding on more than a decade of expertise, CyberShake Study 22.12 is the largest collection of earthquake simulations ever executed by the SCEC. The study was performed on the Oak Ridge Leadership Computing Facility’s Summit supercomputer. The OLCF is a DOE Office of Science user facility located at ORNL.
CyberShake 22.12 exploited updated models of Earth’s structure and novel computational approaches to refine broadband (0-20+ Hz) ground motion simulations for earthquakes. The team’s aim is to decrease uncertainties in current earthquake-hazard evaluations for California. Large earthquakes cause the most destruction but also occur less frequently, making their evolution more challenging to analyze.
“Precise appraisals of the intensity and duration of future earthquake ground movements are crucial for comprehending seismic dangers,” stated Philip Maechling, CyberShake software developer and the associate director for information technology at the SCEC. “We’ve relied on historical observational data to aid us in approximating feasible shaking levels; however, there isn’t adequate observation of near-fault ground motion for current or future requirements.”
CyberShake formulates seismic hazard models by integrating an extensive assortment of existing seismic data. Utilizing the method of probabilistic seismic hazard analysis, CyberShake predicts the powerful ground movements that a particular site is prone to encounter in the future. These predictions are incorporated into regional hazard maps and employed to educate scientists, civil engineers, and the general public about earthquake hazards.
To compute the CyberShake 22.12 hazard model, Maechling’s team employed Pegasus, a workflow management system devised by Ewa Deelman, the research director, and her team at the University of Southern California, or USC, Information Sciences Institute. Maechling’s team continuously executed a diverse array of tasks on Summit over a duration of 10 weeks. Pegasus automatically handled 2.5 petabytes of data, which is the equivalent of about 500 billion pages of standard printed text, including the automated transfer of 70 terabytes to USC’s archival storage.
CyberShake utilizes an updated inventory of all active faults in California and a 3D seismic velocity model to illustrate the Earth’s structure in Southern California. The combination of mountainous terrain and sediment-filled valleys in the region leads to wide variations in the spatial distribution of potent ground movements triggered by large-magnitude earthquakes.
Maechling’s team revamped the algorithms for CyberShake 22.12 to model earthquake ruptures more accurately and to encompass higher-frequency ground motions. The team simulated broadband ground movements for 620,000 earthquakes at 335 locations in Southern California.
CyberShake harnesses comprehensive information about Earth’s structure from fault models and seismic velocity models, in conjunction with physics-based computational modeling, to generate insights about where strong shaking is most probable to occur. This technique has proven to be more precise than previous methods that were based on observation, which were less intricate, less computationally expensive, and less precise.
Ever since the project commenced, Maechling’s team has recognized the value of synergy across multiple scientific disciplines, including geophysics, civil engineering, and computer science. CyberShake harmonizes science and technology from these fields by adapting the most reliable data into physics-based models of the Earth’s active crust. CyberShake data is publicly available and supplied to other researchers and end-users in various formats tailored to their requirements.
The team unveiled CyberShake 22.12 results at the 2023 SCEC Annual Meeting in Palm Springs, California.
CyberShake’s prior outcomes have proven to be valuable for the general public. For instance, the U.S. Geological Survey utilized data from 2020 simulations to inform the National Earthquake Hazards Reduction Program in 2023. Furthermore, the results of CyberShake were employed by the Building Seismic Safety Council and the American Society of Civil Engineers in their revised building code recommendations for Southern California in 2020.
It is too premature to gauge the influence of CyberShake 22.12, but Maechling foresees comparable advancements from this latest study. The CyberShake collaboration is actively engaged in developing a new seismic hazard model that employs a consistent methodology for the state of California.
“We can accomplish a great deal in producing valuable information about seismic hazards without having to wait for the next major earthquake,” Maechling expressed. “Our foremost objective is to leverage high-performance computing to generate precise seismic hazard data that promotes public safety.”
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Source: Quinn Burkhart, ORNL