Do Earthquake-Induced Rotational Ground Motions Matter? A Case Study from the Mw 7.8 Pazarcık Earthquake

Abstract This article investigates the influence of the rotational components of ground motion on the seismic response of structures. Two independent seismic stations, located 30 m apart and within 1 km of the fault rupture, recorded the near-field motions of the 6 February 2023 Mw 7.8 Kahramanmaraş–Pazarcık earthquake. A third, synthetic station was generated using a stochastic frequency-domain approach to estimate the complete set of rotational components. The synthetic records assume that spatial variations in motion depend solely on the interstation separation distance. The resulting rotational response spectra indicate limited sensitivity to the random variability introduced by the synthetic station. For the first time, near-fault rotational ground-motion components—pitch, roll, and yaw—derived from a major earthquake are estimated and used as an input in nonlinear response-history analyses of 3D reinforced concrete building models. The case studies show that including rotational components increases peak core-wall shear forces by 5.3% and peak interstory drift by 13.3%. These findings underscore the importance of measuring and incorporating rotational ground-motion effects in seismic design codes and guidelines to better mitigate the vulnerability of structures near active faults.