City Research Online

Abstract

This study investigates the directionality of spectral accelerations averaged over a period range in 453 ground motions that were recorded in the Turkish strong-motion accelerograph network during the 2023 Kahramanmaraş earthquake sequence. This measure of ground motion intensity, referred to as SaAvg, is computed by using 5%-damped pseudo-acceleration spectral ordinates averaged over a period range from one-fifth to three times the period of interest. Several studies have shown that, compared to the typically used single spectral ordinate, this intensity measure is significantly better correlated with structural damage and, in particular, with structural collapse. Additionally, it is also more sufficient with respect to earthquake magnitude and distance to the source, less sensitive to record scaling, and more predictable. The variation of SaAvg with changes in orientation is carefully studied using two normalised parameters. It is found that, similarly to the directionality of individual spectral ordinates, the directionality of SaAvg also increases with increasing period of the oscillator; however, the level of directionality is smaller. Nonetheless, the dispersion on normalised parameters characterising directionality is in the order of half of that in the directionality of individual spectral ordinates, thus making the directionality of SaAvg significantly more predictable than that of Sa. Models for estimating the directionality in SaAvg are proposed. This study also evaluated for the first time the orientation of maximum SaAvg. Similarly to the orientation of maximum oscillator response in strike-slip earthquakes, it is found that the orientation of maximum SaAvg tends to occur close to the transverse direction from the source. In particular, this study shows that computing the transverse orientation with respect to the point of maximum slip in a finite rupture model leads to better results than doing it using the epicentre.

Publication Type:	Article
Additional Information:	This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s10518-024-02047-z
Publisher Keywords:	Directionality, Ground motion intensity, Averaged spectral acceleration, Orientation of maximum intensity, 2023 Turkiye sequence
Subjects:	Q Science > QE Geology T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

Export

Downloads