Implementation of Distance Conversion Equations in Seismic Hazard
Description:
With an increase in settlements near seismically active faults, accurate Probabilistic Seismic Hazard Assessment (PSHA) close to the fault has become of extreme significance. PSHA incorporates different distance metrics to calculate the seismic hazard of an area. These distances have similar values at large distances from the fault. However, closer to the fault, there can be considerable variation between different distance metrics. As an example, an accelerograph used in the 7.3 MW earthquake in Tabas, Iran was located at an epicentral distance of 57 km but with a rupture distance of only 8 km. These differences can cause large variations in the calculated seismic hazard of the area. Monelli et. al. (2014) discovered a difference of up to 58% in design ground motion while conducting a PSHA sensitivity study using point-based and rupture distances. In this study, we develop empirical equations to convert RJB to other distances and calculate their associated sigma. We use these equations to conduct deterministic and probabilistic studies to present the effect of using consistent distance metrics. The deterministic study is conducted for four sites located at different azimuths from the faults. We have considered a vertical strike-slip fault, a 50 dip-slip fault, an area source of radius 100 km, and a volume source with a depth from 5 km to 10 km. We used Pezeshk et al. (2011), which is based on RRUP distance, as the GMM for all the studies. Our results show a meaningful increase in seismic hazard due to the use of consistent distance metrics. We have also compared our results with other published studies. A method to include the additional variability in PSHA due to distance conversion has also been discussed. The proposed empirical equations are developed based on the geometry of the fault and can be used for any GMMs for seismic hazard calculations.
Session: Advances in Probabilistic Seismic Hazard Analysis and Applications [Poster]
Type: Poster
Date: 4/20/2023
Presentation Time: 08:00 AM (local time)
Presenting Author: Melish Kayastha
Student Presenter: Yes
Invited Presentation:
Authors
Melish Kayastha Presenting Author Corresponding Author mkyastha@memphis.edu University of Memphis |
Shahram Pezeshk spezeshk@memphis.edu University of Memphis |
Behrooz Tavakoli btavakol@bechtel.com Bechtel Power Corporation |
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Implementation of Distance Conversion Equations in Seismic Hazard
Category
Advances in Probabilistic Seismic Hazard Analysis and Applications