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http://hdl.handle.net/2122/13078
Authors: | Soldati, Gaia* Zaccarelli, Lucia* Faenza, Licia* |
Title: | Spatio-temporal seismic velocity variations associated to the 2016–2017 central Italy seismic sequence from noise cross-correlation | Journal: | Geophysical Journal International | Series/Report no.: | /219 (2019) | Issue Date: | 2019 | DOI: | 10.1093/gji/ggz429 | Keywords: | seismic noise cross-correlations noise-based monitoring seismic velocity variations |
Subject Classification: | 04. Solid Earth 04.06. Seismology 05.01. Computational geophysics |
Abstract: | We investigate the temporal changes of crustal velocity associated to the seismic sequence of 2016–2017, which struck central Italy with a series of moderate to large earthquakes. We cross- correlate continuous recordings of 2 yr of ambient seismic noise from a network of 28 stations within a radius of 90 km around Amatrice town. We then map the spatio-temporal evolution of the velocity perturbations under the effect of subsequent earthquakes. Coinciding with each of the three main shocks of the sequence we observe a sudden drop of seismic velocity which tends to quickly recover in the short term. After the end of the strongest activity of the sequence, the coseismic velocity changes display gradual healing towards pre-earthquake conditions following a quasi-linear trend, such that by the end of 2017 about 75 per cent of the perturbation is recovered. The spatial distribution of the velocity drop fluctuates with time, and the area that shows the most intense variations beyond the ruptured fault system elongates in the NE direction. This zone roughly corresponds to a region of foredeep sedimentary deposits consisting of highly hydrated and porous sandstones, which respond to the passage of seismic waves with increased pore pressure and crack number, leading to a reduction of the effective relative velocity. | Description: | This article has been accepted for publication in Geophysical Journal International ©: The Authors 2019. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Uploaded in accordance with the publisher's self-archiving policy. |
Appears in Collections: | Article published / in press |
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File | Description | Size | Format | |
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2019GJI_Soldati-etal.pdf | main article | 10.84 MB | Adobe PDF | View/Open |
2019GJI_Soldati-etal.supp.pdf | supplementary material | 1.41 MB | Adobe PDF | View/Open |
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