188宝金博页面版

Vol.:(0123456789)Acta Geophysica (2025) 73:5207–5220 https://doi.org/10.1007/s11600-025-01670-xRESEARCH ARTICLE - SOLID EARTH SCIENCESInf l uence of the rotational and translational component rotation on the H/V spectra despite of the applied spectrum estimation methodDariusz Nawrocki 1 Received: 2 March 2025 / Accepted: 8 July 2025 / Published online: 2 August 2025 © The Author(s) 2025AbstractThe article presents horizontal-to-vertical (H/V) spectral ratios estimated for the rotated horizontal components of the reg-istered signals. Estimations were performed for rotational and translational signals using waveforms from mining-induced seismic events. The amplif i cation curves were estimated for each case of the axis rotation using the Fourier Spectrum Ampli-tude (FSA) and the Response Spectrum Analysis (RSA). Estimating the amplif i cation spectrum for the rotated horizontal components is a method that allows determining the directional amplif i cation ef f ect, connected with the local anisotropy and fault occurrence. The Quaternary fault presence characterises the closest proximity of the station. Therefore, the surveys assumed analysis of the possibility and limitations of the directional amplif i cation ef f ect estimation by using records of rota-tional and translational motion as well as both approaches of the H/V estimation. The comparisons presented the limitation of the RSA approach in the estimation rotational H/V curve, which was an ef f ect of the sensor settings on the pedestal. The directional amplif i cation ef f ect presented a perpendicular orientation to the close-distance fault, similar to rotational and translational motion analysis assuming the FSA approach.Keywords HVSR · Induced seismicity · Rotational ground motion · Time history rotation · Response spectrum · Directional amplif i cation ef f ectIntroductionThe directional amplif i cation ef f ect refers to amplifying the signal along site-specif i c azimuth in the horizontal plane, whose origin is connected with the anisotropy of local sub-soil geological structures (Rupakhety and Sigbjörnsson 2013; Pinzón et al. 2019; Nawrocki et al. 2024a, b). The mentioned ef f ects are mainly observed on both earthquake wavef i eld and ambient noise, which suggests that local sub-soil geological structure plays an important role in its gen-eration. Considering research presented by Pischiutta et al. (2014, 2018) and Burjànek et al. (2014b), the directional amplif i cation ef f ect may involve a signif i cant areal extent, up to several kilometres of distance. So far, the ef f ect of the directional amplif i cation was noticed in various geological conditions, in which can be distinguished: fractured rock slopes and landslides (Del Gaudio and Wasowski 2007; Moore et al. 2011; Burjánek et al. 2012; Häusler et al. 2019); the volcanic zones (e.g. Di Giulio et al. 2009; Falsaperla et al. 2010; Petrosino et al. 2012; Panzera et al. 2020;) and also fault zones (Pischiutta et al. 2014; Hailemikael et al. 2016; Di Giulio et al. 2019). Despite the geological frame-work, the directional amplif i cation tended to be in the trans-versal direction to the primary orientation of the predomi-nant fractured fi eld in the fault damage zones (e.g. Rigano et al., 2008; Di Giulio et al. 2009; Pischiutta et al. 2014; Vignaroli et al. 2019; Panzera et al. 2020) and also on frac-tured rock slopes (e.g. Burjánek et al. 2010). The potential mechanism of the directional amplif i cation generation is related to the generation of the polarised ground motion by the fractures, in which the maximum amplif i cation is in the transversal direction to their strike (Burjanek and Kleinbrod 2019). The ef f ect is signif i cantly dependent on the stif f ness, depth, amount of fractures, and inertial mass of the fractured rocks.Edited By Prof. Maciej Mendecki. * Dariusz Nawrocki dariusz.nawrocki@igf.edu.pl1 Institute of Geophysics, Polish Academy of Sciences, Ksi?cia Janusza 64, Warszawa, Poland