GNGTS 2018 - 37° Convegno Nazionale

GNGTS 2018 S essione 1.1 139 with the weight coefficients S (mm). Both temporal function and spatial distribution of the first independent component, IC1, agree with what we would expect from afterslip occurring on the two faults involved in the seismic sequence. The IC2 exhibits a large time scale, and it is probably related to a multiannual signal (e.g., Serpelloni et al. , 2018; Silverii et al. , 2016). The temporal function of IC3 shows a rapid increase in the early postseismic stage (first 10 days after the May 20 mainshock). Its spatial response is maximum at MO05, the closest station to the epicentral area and we interpret IC3 as the poroelastic response at the surface. The locations of the InSAR (SBAS) time series at points 1 and 2 [from Albano et al. (2017) and Cheloni et al. (2016)] are shown in Fig. 1a. Poroelastic model. We use the software written by Wang and Kümpel (2003), which allows us to represent a horizontal-layered half-space with different elastic and hydraulic parameters. Fig. 1 - (A) Map of the investigated area. Blue squares: GPS stations. Black rectangles: projection of the two faults at the surface. Orange points: seismic events during the Emilia-Romagna seismic sequence in the first 30 days after the May 20 mainshock (Govoni et al. , 2014). Yellow stars: May 20 (Easternmost) and May 29 (Westernmost) mainshocks epicenters. Red and purple crosses: locations of the InSAR (SBAS) time series at points 1 and 2, respectively. (B) Blue: temporal evolution (V, non-dimensional) of the three independent components (ICs) necessary to reproduce the horizontal GPS position time series. Red: low-pass filtered temporal functions V. (C) Horizontal spatial distribution (U) of the three ICs, where S is a weight coefficient (in mm) necessary to rescale each IC contribution in explaining the original data.