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Schiappapietra, Erika
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Schiappapietra, Erika
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- PublicationOpen AccessFling Effects from Near‐Source Strong‐Motion Records: Insights from the 2016 M w 6.5 Norcia, Central Italy, Earthquake(2019)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; We propose a semiautomatic processing scheme (extended BASeline Correction [eBASCO]) for recovering the tectonic fling from near‐source records. The method, based on a piecewise linear detrend of the strong‐motion (SM) recordings, is applied to reconstruct the ground displacement field of the 30 October 2016 Mw 6.5 earthquake in central Italy. The robustness of the results is checked against geodetic measurements, remote sensing data, ground‐motion simulations, and existing empirical models for fling amplitude. The outcomes of eBASCO are analyzed with the goal of testing its capability to preserve long‐period content in near‐source SM recordings affected by tectonic fling, different from standard processing schemes based on bandpass filtering. Comparison of peak ground displacements, peak ground velocities, and spectral displacements shows that long‐period ground motion recorded over and in proximity of the fault can be underestimated by standard processing. Spectral displacement ordinates can diverge up to the 25% for periods longer than 5 s when an appropriate baseline correction is made.1307 78 - PublicationOpen AccessFling-Step Recovering from Near-Source Waveforms Database(2021-02-04)
; ; ; ; ; We present an upgraded processing scheme (eBASCO, extended BASeline COrrection) to remove the baseline of strong-motion records by means of a piece-wise linear detrending of the velocity time history. Differently from standard processing schemes, eBASCO does not apply any filtering to remove the low-frequency content of the signal. This approach preserves both the long-period near-source ground-motion, featured by one-side pulse in the velocity trace, and the offset at the end of the displacement trace (fling-step). The software is suitable for a rapid identification of fling-containing waveforms within large strong-motion datasets. The ground displacement of about 600 three-component near-source waveforms has been recovered with the aim of (1) extensively testing the eBASCO capability to capture the long-period content of near-source records, and (2) compiling a qualified strong-motion flat-file useful to calibrate attenuation models for peak ground displacement (PGD), 5% damped displacement response spectra (DS), and permanent displacement amplitude (PD). The results provide a more accurate estimate of ground motions that can be adopted for different engineering purposes, such as performance-based seismic design of structures.454 27 - PublicationOpen AccessFling-step recovering from near-source waveforms and ground displacement attenuation models(egu, 2020-05-07)
; ; ; ; ; ; ; ; ; We present a processing scheme (eBASCO, extended BASeline COrrection) to remove the baseline of strong-motion records by means of a piece-wise linear de-trending of the velocity time history. Differently from standard processing schemes, eBASCO does not apply any filtering to remove the low-frequency content of the signal. This approach preserves both the long-period near-source ground-motion, featured by one-side pulse in the velocity trace, and the offset at the end of the displacement trace (fling-step). Hence, the software is suitable for the identification of fling-containing strong-motion waveforms. Here, we apply eBASCO to reconstruct the ground displacement of more than 400 three-component near-source waveforms recorded worldwide (NESS1, http://ness.mi.ingv.it/; Pacor et al., 2019) with the aim of: 1) extensively testing the eBasco capability to capture the long-period content of near-source records; 2) calibrating attenuation models for peak ground displacement (PGD), 5% damped displacement response spectra (DS), permanent displacement amplitude (PD) and period (Tp). The results could provide a more accurate estimate of ground motions, to be adopted for different engineering purposes such as performance-based seismic design of structures.133 66 - PublicationOpen AccessEmpirical predictive models for fling step and displacement response spectra based on the NESS databaseThe characterization of the fling-step represents a challenging task due to the shortage of near-source records with permanent tectonic displacement and the limitation in retrieving the fling-amplitude from accelerometric waveforms. In recent years, innovative ground-motion processing techniques have been developed for a more accurate estimation of both fling-displacements and spectral displacements in contrast to traditional bandpass filtering, although their application is still unusual. In this paper, we exploit the newly released dataset of the Near-Source Strong-motion records (NESS2) uniformly processed with the extended BASeline COrrection technique (eBASCO), against which we propose: (1) a new empirically-based ground motion model (GMM) for the prediction of the fling-step, and (2) an adjustment factor of the spectral displacements predicted by a reference GMM to account for the contribution of the fling-step at long periods. Such models are in agreement with observations and existing GMMs, and thus could be advantageously employed in seismic hazard analyses.
228 4 - PublicationOpen AccessBayesian rupture imaging in a complex medium: The 29 May 2012 Emilia, Northern Italy, earthquake(2017-07-31)
; ; ; ; ; ; ;; ;; ;We develop a new approach to image earthquake rupture from strong motion data. We use a large data set of aftershock waveforms, interpolated over the seismic fault to obtain Green’s function approximations. Next we deploy a Bayesian inversion method to characterize the slip distribution, the rupture velocity, the slip duration, and their uncertainties induced by errors in the Green’s functions. The method is applied to the 29 May 2012 Mw 6 Emilia earthquake, which ruptured a fault buried below the Po Plain sediments (Northern Italy). Despite the particularly complex wave propagation, the near-field strong motion observations are well reproduced with 15 rupture parameters. The rupture and slip velocities were notably slow (~0.5 Vs and <0.5 m/s, respectively), implying that the fault was difficult to break. This method opens some perspectives for earthquake rupture studies in areas where numerical simulations suffer from imprecise knowledge of the velocity structure.214 28