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Influence of Site Effects’ Spatial Variability on Spatially Variable Ground Motion Intensity Measures

Description: 

Spatially variable ground motions (GMs) challenge the assessment and design of largely distributed infrastructure in earthquake-prone areas. The spatial variability of GMs is a complex function of source heterogeneities, varying ray propagation paths, and varying local soil conditions. Because soil properties can be spatially correlated at nearby locations, the expected site response affecting civil infrastructure systems will also be spatially correlated. Therefore, the spatial correlation structure of soil properties can inform the spatial correlation of GM intensity measures (IMs). Current spatial correlation models treat site effects either as a fixed amplification factor or as randomized amplifications, but site effects are neither. In this work, we evaluate the significance of the spatial correlation for different site parameters corresponding to Kiban-Kyoshin Network (KiK-net) stations with respect to the observed spatial correlation of GM IMs residuals from collocated events including the 2011 Tohoku earthquake sequence. This earthquake sequence caused significant damage, such as pipeline ruptures due to the strong shaking in the Tohoku and Kanto regions. These co-located events provide an opportunity to capture site-specific correlations while isolating the influence of both source and path effects on correlation structures. Particularly, the residual analysis of GM IMs (e.g., spectral acceleration; SA) was performed using a ground motion model (GMM) to remove the effects of attenuation with distance and further examine the correlation of the IMs at different periods of interest. Preliminary findings show that the spatial distribution of GM IMs is affected by the variation of geology and topographic conditions captured by site parameters.

Session: Regional-Scale Hazard, Risk and Loss Assessments [Poster Session]

Type: Poster

Date: 5/3/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Cristina

Student Presenter: Yes

Invited Presentation: 

Authors