Empirical Evidence of Frequency-Dependent Directivity Effects From Small-To-Moderate Normal Fault Earthquakes in Central Italy
Autor
Colavitti, Leonardo
Lanzano, Giovanni
Sgobba, Sara
Datum vydání
2022Publikováno v
Journal of Geophysical Research: Solid EarthRočník / Číslo vydání
127 (6)ISBN / ISSN
ISSN: 2169-9313Metadata
Zobrazit celý záznamKolekce
Tato publikace má vydavatelskou verzi s DOI 10.1029/2021JB023498
Abstrakt
Rupture directivity and its potential frequency dependence is an open issue within the seismological community, especially for small-to-moderate events. Here, we provide a statistical overview based on empirical evidence of seismological observations, thanks to the large amount of high-quality seismic recordings (more than 30,000 waveforms) from Central Italy, which represents an excellent and almost unique natural laboratory of normal faulting earthquakes in the magnitude range between 3.4 and 6.5 within the time frame 2008-2018. In order to detect an anisotropic distribution of ground motion amplitudes due to the rupture directivity, we fit the smoothed Fourier Amplitude Spectra (FAS) cleared of source-, site- and path-effects. According to our criteria, about 36% of the analyzed events (162 out of 456) are directive and the distribution of rupture direction is aligned with the strikes of the major faults of the Central Apennines. We find that the directivity is a band-limited phenomenon whose width may extend up to five times the corner frequency. The results of this research provide useful insights to parameterize directivity, to be explicitly implemented in future ground motion modeling and scenario predictions.
Klíčová slova
source directivity effects, ground motion analysis, nonergodic approach, normal faults, directivity bandwidth, directivity parameterization for empirical shaking scenarios
Trvalý odkaz
https://hdl.handle.net/20.500.14178/1672Licence
Licence pro užití plného textu výsledku: Creative Commons Uveďte původ 4.0 International