Investigating the Influence of Site-Specific Spatial Variability on Ground Motion Intensity Measures via Multidimensional Site Response Analyses at the Treasure Island Downhole Array
Description:
Multidimensional ground response analyses (GRAs) are gradually gaining more interest due to the growing evidence that demonstrates the imperfect ability of one-dimensional (1D) GRAs to match recorded ground motions at many borehole array sites. However, there is rarely a multidimensional subsurface model available for these analyses. The lack of affordable and reliable site characterization methods to quantify spatial variability in subsurface conditions, particularly regarding shear wave velocity (Vs) measurements needed for GRAs, hinders future progress in accurate seismic site response modeling. We present a framework called the ‘H/V geostatistical approach’ that can be used to develop site-specific three-dimensional (3D) Vs models and we share insights that have been gained from implementing these 3D Vs models in multidimensional GRAs at the Treasure Island Downhole Array (TIDA). Using the H/V geostatistical approach, a site-specific, large-scale, 3D Vs model has been developed to a depth of 150 m over the entirety of Treasure Island (an area approximately 1.6 km × 1.0 km). By performing multidimensional finite element analyses using the recorded ‘rock’ ground motions at the TIDA, we investigate the influence of subsurface spatial variability on different ground motion intensity measures, and we ground truth these results against recorded surface ground motions at the TIDA. We show that the site-specific 3D Vs model is capable of replicating wave scattering and more complex wave propagation phenomena observed in the recorded ground motions at the TIDA.
Session: Ground Truthing Multidimensional Site Response Analyses at Borehole Array Sites [Poster]
Type: Poster
Date: 4/20/2023
Presentation Time: 08:00 AM (local time)
Presenting Author: Mohamad M. Hallal
Student Presenter: No
Invited Presentation:
Authors
Mohamad Hallal Presenting Author Corresponding Author mhallal@berkeley.edu University of California, Berkeley |
Brady Cox brady.cox@usu.edu Utah State University |
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Investigating the Influence of Site-Specific Spatial Variability on Ground Motion Intensity Measures via Multidimensional Site Response Analyses at the Treasure Island Downhole Array
Category
Ground Truthing Multidimensional Site Response Analyses at Borehole Array Sites