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Estimating Hazard From Crustal Sources: An Empirical Observation Approach

Description: 

This study aims to estimate ground motion near the source. This estimation depends, at the very least, on factors such as the rupture type, the specific path of propagation, and site parameters. We employ an empirical approach based on the analysis of the Near Source Strong Motion database (NESS 2.0) (Sgobba et al., 2021). The empirical approach involves interpreting and plausibly estimating the main characteristics influencing rupture, which significantly modifies ground motions across various spectral periods in the near source. We estimate and compare Ground Motion Models (GMM) with intensity real data obtained from various tectonic regions and earthquake sources, assessing their residuals. Our analysis is structured into two parts. The first part focuses on individual parameters in each GMM for events with similar slip-rupture conditions. The second part involves a nested-residuals analysis, which can be initially divided into terms capturing effects not parametrized by GMMs.

The directivity effect causes shear-wave energy from all points on the fault to arrive at nearly the same time at the station in the direction of the rupture's propagation. Similarly, rupture velocity increases ground motion as the radiation for each point into the fault occurs faster, arriving at the station in a shorter time interval (Aagard et al., 2001). The significance of hypocentral depth lies in its control over the radiation pattern (Dujardin et al., 2021). Additionally, the depth of the top of the rupture influences slip behavior; as it deepens, fewer slips (shaking) occur in the softer surface material of the media (Aagard et al., 2001). Conversely, seismogenic depth determines the potential area involved in the rupture, as significant earthquakes (greater than ~6) typically nucleate at the base of the seismogenic layer, rupturing the entire seismogenic crust in depth (Scholz, 2019). This influence extends to the earthquake size.

Session: From Earthquake Recordings to Empirical Ground-Motion Modelling [Poster Session]

Type: Poster

Date: 5/2/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Daniel

Student Presenter: Yes

Invited Presentation: 

Authors