The interseismic velocity field of the central Apennines from a dense GPS network

Abstract

<p>Since 1999, we have repeatedly surveyed the central Apennines through a dense survey-style geodetic network, the Central Apennines Geodetic Network (CAGeoNet). CAGeoNet consists of 123 benchmarks distributed over an area of ca. 180 km × 130 km, from the Tyrrhenian coast to the Adriatic coast, with an average inter-site distance of 3 km to 5 km. The network is positioned across the main seismogenic structures of the region that are capable of generating destructive earthquakes. Here, we show the horizontal GPS velocity field of both CAGeoNet and continuous GPS stations in this region, as estimated from the position–time series in the time span from 1999 to 2007. We analyzed the data using both the Bernese and GAMIT software, rigorously combining the two solutions to obtain a validated result. Then, we analyzed the strain-rate field, which shows a region of extension along the axis of the Apennine chain, with values from 2 × 10<span><sup>–9</sup></span> yr<span><sup>–1</sup></span> to 66·× 10<span><sup>–9</sup></span> yr<span><sup>–1</sup></span>, and a relative minimum of ca. 20 × 10<span><sup>–9</sup></span> yr<span><sup>–1</sup></span> located in the L'Aquila basin area. Our velocity field represents an improved estimation of the ongoing elastic interseismic deformation of the central Apennines, and in particular relating to the area of the L'Aquila earthquake of April 6, 2009.</p>

Coseismic displacement waveforms for the 2016 August 24 Mw 6.0 Amatrice earthquake (central Italy) carried out from High-Rate GPS data

“…The main shock triggered an aftershock sequence that involved a crustal volume extending SE-NW for ~30 km and down to ~15 km of depth. The main shock and the largest part of aftershock events show focal solutions (http://cnt.rm.ingv.it/tdmt.html, Scognamiglio et al, 2016; http://www.bo.ingv.it/RCMT) characterized by almost pure extension on NW-SE fault planes, in agreement with geodetic measurements of the main event (INGV CNT GPS Working Group, 2016;Cheloni et al, 2016) and with the interseismic SW-NE extension characterizing this sector of the Apennines (e.g., Galvani et al, 2012;D'Agostino, 2014).…”

GPS observations of coseismic deformation following the 2016, August 24, Mw 6 Amatrice earthquake (central Italy): data, analysis and preliminary fault model

“…The first data for NRCI after the mainshock is relative to August 26. In the following hours and days, several GPS instruments have been installed at geodetic markers belonging to the CaGeoNet network (Anzidei et al, 2008;Galvani et al, 2012) and the first rapid solution has been integrated (see Figure 2) with data from continuous GPS networks managed by the Italian Civil Protection Department (DPC) and the Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA). In particular, 7 sites of the CaGeoNet network have been re-occupied following the indications from a forward coseismic model implemented from the mainshock focal solution and selecting sites for which relatively longer time-series where available, in order to allow a rather robust estimate of the pre-(i.e., interseismic) seismic velocities.…”

“…The black squares show the position of the INGV-RING stations (http://ring.gm.ingv.it). The grey squares show the position of the CaGeoNet network (Anzidei et al 2008;Galvani et al, 2012)…”

Post‐Seismic Deformation Related to the 2016 Central Italy Seismic Sequence From GPS Displacement Time‐Series

“…We use in total 85 GPS stations in this work (Fig. 2) with almost continuous data in the time-interval 2012-2019 integrated by a few campaign-mode stations, belonging to the CaGeoNet network (Galvani et al, 2013), that have been occupied almost continuously after the Amatrice mainshock (see Cheloni et al, 2016 for details). The dataset also includes few stations in the Adriatic on-shore and off-shore (Palano et al, 2020), managed by the private company ENI S.p.A.…”