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

Abstract

<p>We used continuous Global Positioning System (GPS) measurements to infer the fault geometry and the amount of coseismic slip associated to the August 24, 2016 Mw 6 Amatrice earthquake. We realized a three dimensional coseismic displacement field by combining different geodetic solutions generated by three independent analyses of the raw GPS observations. The coseismic deformation field described in this work aims at representing a consensus solution that minimizes the systematic biases potentially present in the individual geodetic solutions. Because of the limited number of stations available we modeled the measured coseismic displacements using a uniform slip model, deriving the geometry and kinematics of the causative fault, finding good agreement between our geodetically derived fault plane and other seismological and geological observations. <strong></strong></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).…”

“…Because of their proximity to the epicenter, they experi-enced the largest coseismic dynamic displacements: AMAT shows larger values of peak-topeak displacements on the radial component (~16.6 cm) than on the transverse one (~8.2 cm), whereas NRCI shows generally lower peak-to-peak displacements than AMAT, but larger on the transverse component (~15.0 cm) than on the radial one (~8.2 cm). The comparisons between the GD2P and TRACK results are also shown in Figure 2B at some sites located between ~35 and ~50 km from the epicenter, where the static deformation due to the near field is expected to be negligible (as shown in Cheloni et al, 2016) or within the accuracy of the HRGPS time series. The GPSgrams shown from the top to the bottom of the Figure 2B are sorted by increasing azimuth angle and seem to point out the SH arrivals on the T component and the surface waves arrivals on the R component in the time ranges 10-15 s and 15-25 s, respectively.…”