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Source, Path, and Site Effects on the Peak Velocity From the 2023 Pazarcik, Turkey Mainshock

Description: 

The peak ground velocities (PGV) from the Feb 2023 Pazarcik, Turkey earthquake mainshock were above average with a mean residual of 0.5 natural log units (factor of 1.65) for sites within 30 km of the rupture compared to the Abrahamson et al. (2014) ground motion model (GMM). Large PGV can be caused by several factors: forward directivity, fling, close distance to an asperity, path effects due to the 3-D crustal structure, and site effects. To determine the relative contribution of these effects to the large PGV values, we first baseline corrected the mainshock recording to recover the static displacement and remove the fling effects from the velocity time series. We then used the ground motions from M4-M5 aftershocks to estimate the site terms and non-ergodic path terms for a preliminary non-ergodic GMM using the iterative variable coefficient model (VCM) approach method of Sung et al. (2023). Morving the site and path terms removes some of the complexity from the distribution of the PGV. Finally, we compared the mainshock PGV residuals relative to the non-ergodic GMM to determine the correlation with the directivity model parameters of Bayless et al. (2021) and with the distance to the nearest asperity.

Session: February 2023 Mw 7.8 Earthquake Sequence in Turkey [Poster]

Type: Poster

Date: 4/19/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Chih-Hsuan Sung

Student Presenter: No

Invited Presentation: 

Authors