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Modeling the Spatial Correlation in Ground Motion Residuals of M 7.7 Myanmar Earthquake

Description: 

Geographically distributed infrastructure systems are affected by ground shaking during earthquakes due to the extensive impact over a large region. To enable the seismic risk assessment of spatially distributed infrastructures and systems, it is crucial to model the spatial correlation of ground motions. A major source of this correlation comes from ground motion residuals- the difference between observed and predicted ground motions. Ground motion residuals consist of two primary components: between-event residuals and within-event residuals. The between-event residual reflects systematic errors that occur from one earthquake to another, while the within-event residual accounts for the variability of ground motions across different sites during a single earthquake. Research indicates that ignoring the correlation of within-event residuals can result in unrealistic or inaccurate seismic risk estimates for the system, particularly in systems relying on redundant components. Ground motion residual correlation models have been developed for various geographic regions and tectonic regimes. This study examines the correlation of ground motion residuals, specifically focusing on within-event residuals, for twelve earthquakes that occurred in Myanmar, including the recent M 7.7 earthquake in Mandalay in 2025. We utilize USGS earthquake catalogs to obtain observed ground motions, and we refer to 2014 active crustal ground motion models for predicted ground motions, both measured in terms of Peak Ground Acceleration (PGA). We used semivariogram analysis to study the correlation structure of ground motion residuals. Three standard correlation models (exponential, Gaussian, and Spherical) are used to characterize how correlation decreases as the distance between sites increases. The findings highlight the spatial correlation in ground motion residuals, which can aid in developing shake maps and evaluating seismic risk for spatially distributed systems.

Session: Late-breaking on Recent and Future Large Earthquakes [Poster]

Type: Poster

Date: 4/15/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Amirreza

Student Presenter: Yes

Invited Presentation: 

Poster Number: 153

Authors