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Fault-Displacement Models for Aggregate, Principal, and Distributed Displacements

Description: 

As part of this study, we present new fault displacement models (FDMs) for aggregate, principal, and distributed displacements based on the net component of the slip vector. The FDMs are developed based on the Fault Displacement Hazard Initiative Project Dataset comprised of 75 events with magnitude ranging from 4.9 to 8.0. The model for the aggregate displacement is formulated first in the wavenumber domain to incorporate seismology-based constraints for the extrapolation of the magnitude scaling of median displacements to large-magnitude events and then transformed to the space domain to facilitate its implementation. The space domain model is then empirically adjusted to account for small-to-moderate magnitude scaling, displacement tapering near the edges, and the effect of segmentation. Segments are used in the development of the original model to capture the slip variability better. For applications in which segments cannot be determined in advance, an FDM is provided, with the number, lengths, and locations of the segments included as part of the aleatory variability. The principal-displacement FDM is developed next as an adjustment to the aggregate-displacement FDM. The total distributed displacement is determined based on the aggregate to principal difference, and probabilistic models are developed to compute the number, location, and partition of total distributed slip into individual ruptures. A key feature of the new FDMs is the use of a power-normal distribution for the aleatory variability of aggregate and principal displacements, leading to narrower distributions of displacements for large magnitudes compared to existing FDMs. Furthermore, for large-magnitude earthquakes, the expected maximum displacements implied by the proposed model are consistent with the observed maximum displacements along strike, supporting the narrower shape of the upper tail of the power-normal distribution for large-magnitude events.

Session: Assessing Seismic Hazard for Critical Facilities and Infrastructure – Insights and Challenges - II

Type: Oral

Date: 5/3/2024

Presentation Time: 05:15 PM (local time)

Presenting Author: Grigorios

Student Presenter: No

Invited Presentation: 

Authors