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Site-Specific, Extended Shakemaps for Earthquake Engineering Applications

The U.S. Geological Survey product that gives the estimated shaking intensity for earthquakes globally is called ShakeMap. It provides maps of estimated ground motion intensity metrics (IMs) in the minutes and hours following an earthquake. Providing this information as quickly as possible is critical for emergency responders and the public. In contrast, the response timeline for specialized use cases such as code compliance, damage analyses, fragility curve development, and examining triggering thresholds for ground failure is less compressed than for emergency responders, and more detailed information would be useful. Here, we describe recently developed tools to provide ShakeMap estimates of spectral acceleration in 22 periods (matching the current U.S. National Seismic Hazard Model periods) as well as orientation-independent components. We refer to ShakeMap products that include these extensions as “extended ShakeMaps.” The added level of complexity motivated us to also develop a user-friendly tool in Python called the “ShakeMap Sampling Tool” (SST) that gives all the estimated shaking metrics for a specific location (or list of locations). Additionally, we developed a web application where users can input locations of interest and view/download the SST results. Through this system, we can also provide composite ShakeMaps—maps of the maximum value of each IM across a sequence—which is especially useful for overall loss estimates. Composite ShakeMaps can also be used to provide a site-specific shaking history for analyzing repeated shaking to structures. The composite ShakeMap, combined with the extended IM products, facilitates forensics at building and infrastructure sites for which damage may be of concern, as described in the Disproportionate Damage Earthquake trigger specified in the International Existing Building Code and in developing ATC-145 “Guidelines for Post-Earthquake Assessment, Repair, and Retrofit of Buildings”.

Session: Creating Actionable Earthquake Information Products - I

Type: Oral

Room: Tikahtnu Ballroom C

Date: 5/1/2024

Presentation Time: 08:15 AM (local time)

Presenting Author: Eric Thompson

Student Presenter: No

Additional Authors