Please use this identifier to cite or link to this item:
http://hdl.handle.net/2122/12361
Authors: | Marcucci, Sandro* Milana, Giuliano* Hailemikael, Salomon* Carlucci, Giorgia* Cara, Fabrizio* Di Giulio, Giuseppe* Vassallo, Maurizio* |
Title: | The Deep Bedrock in Rome, Italy: A New Constraint Based on Passive Seismic Data Analysis | Journal: | Pure and Applied Geophysics | Series/Report no.: | 6/176 (2019) | Publisher: | Springer International Publishing | Issue Date: | 19-Feb-2019 | DOI: | 10.1007/s00024-019-02130-6 | Keywords: | Ambient vibrations horizontal-to-vertical spectral ratio surface-waves dispersion curve joint inversion |
Subject Classification: | 04.06. Seismology | Abstract: | Seismic resonance inside sedimentary basins severely influences ground shaking at the free surface in case of earthquakes. Starting from few observations of a low-frequency resonance in the historical center of Rome, Italy, we performed several single-station ambient vibration measures to verify and estimate the resonance frequency in a wide area of the city by Horizontal-to-Vertical spectral ratio method. We verified a stable low-frequency peak in the range 0.3–0.4 Hz. Recordings of August 24th 2016, Mw 6.0 Amatrice earthquake, available both inside and outside the basin of Rome, confirm the presence of high-energy components at frequencies of 0.2–0.4 Hz within the basin. These observations support the hypothesis of a deep seismic impedance contrast responsible for the low frequency resonance. To infer the depth range of subsoil deposits related to this impedance contrast, we analyzed ambient vibration data recorded by 2-D seismic arrays aiming at retrieving the shear-wave velocity structure up to relevant depths. To increase the investigation depth (up to 2000 m), we jointly inverted for Rayleigh-waves dispersion and ellipticity curves and resonance frequency. The shear-wave velocity profile shows two main discontinuities at depths of about 500 m and 1800 m that can be related to the bottom of the Plio-Pleistocene filling of the Rome basin and to the top of the basal limestone formation, respectively. These results fill a gap of knowledge about the deep velocity structure in the city that may be helpful for ground-motion scenario studies. |
Appears in Collections: | Article published / in press |
Files in This Item:
File | Description | Size | Format | Existing users please Login |
---|---|---|---|---|
Marcucci2019_Article_TheDeepBedrockInRomeItalyANewC-2.pdf | 2.07 MB | Adobe PDF |
WEB OF SCIENCETM
Citations
50
3
checked on Feb 10, 2021
Page view(s)
305
checked on Mar 27, 2024
Download(s)
19
checked on Mar 27, 2024