Hydrologically Induced Karst Deformation: Insights From GPS Measurements in the Adria‐Eurasia Plate Boundary Zone

Abstract

We apply a blind source separation algorithm to the ground displacement time series recorded at continuous Global Positioning System (GPS) stations in the European Eastern Alps and Northern Dinarides. As a result, we characterize the temporal and spatial features of several deformation signals. Seasonal displacements are well described by loading effects caused by Earth surface mass redistributions. More interestingly, we highlight a horizontal, nonseasonal, transient deformation signal, with spatially variable amplitudes and directions. The stations affected by this signal reverse the sense of movement with time, implying a sequence of dilatational and compressional deformation that is oriented normal to rock fractures in karst areas. The temporal evolution of this deformation signal is correlated with the history of cumulated precipitations at monthly time scales. This transient horizontal deformation can be explained by pressure changes associated with variable water levels within vertical fractures in the vadose zones of karst systems. The water level changes required to open or close these fractures are consistent with the fluctuations of precipitation and with the dynamics of karst systems.

New insights into active tectonics and seismogenic potential of the Italian Southern Alps from vertical geodetic velocities

“…The GPS velocities have been estimated analyzing the position time series, realized in the IGb08 reference frame, of all stations having an observation time span longer than 5 years (in the 1998.0-2017.5 time span, in order to be consistent with IGS08 products and the reference frame), in order to minimize possible biases in the linear trend estimation due to seasonal signals (Blewitt and Lavallée, 2002) and non-seasonal hydrological deformation signals (Serpelloni et al, 2018).…”

“…However, despite geological or geomorphological evidence of Quaternary deformation (Benedetti et al, 2000;Galadini et al, 2005), the identification of active faults responsible for large past earthquakes is not conclusive. The same area is interested by non-tectonic deformation transients associated with the hydrological cycle in karst regions and precipitations, which are well tracked and described by continuous GPS stations (Devoti et al, 2015;Serpelloni et al, 2018). These deformation transients, which mainly affect the horizontal components of ground displacements, make the estimate of the long-term horizontal tectonic deformation rates more challenging.…”

Poroelasticity and Fluid Flow Modeling for the 2012 Emilia-Romagna Earthquakes: Hints from GPS and InSAR Data

“…As the second IC exhibits a large time scale, one hypothesis could be that it represents a multiannual signal. Multiannual signals in the GPS displacement time series, in fact, have been recently highlighted in the Apennines and in the Alps [29,30] and associated with variations of hydrological processes acting at different spatial scales. The temporal function of the third IC shows a rapid increase in the early postseismic stage (first 10 days after the May 20 mainshock).…”

“…This method, applied to geodetic time series, performs a spatiotemporal separation of the geodetic data into a limited number of signals, subsequently interpreted as the actual physical sources that generated the observed displacements. This method has been successfully used to extract tectonic and nontectonic (e.g., mainly related with hydrology) deformation signals in the GPS time series in different settings [26][27][28][29]. In particular, each source has a specific spatial distribution (U) and follows a specific temporal evolution (V).…”

Sea Level Rise Scenario for 2100 A.D. in the Heritage Site of Pyrgi (Santa Severa, Italy)

“…Both these stations have a robust time series that span for 2004-2019 for TOLF (about 15 years) and 2012-2019 for MAR8 (about 7 years), respectively (Fig.5). The GPS data analysis has been carried out following the procedures already described in [24] and updated in [25] adopting a three-step procedure using the GAMIT/GLOBK V10.7 (Herring et al, 2015) and QOCA software. This is part of a continental-scale GPS solution, including >3000 stations [26].…”