February 2017 Western Turkey Earthquake Swarm Sentinel-1 TOPS Differential Interferogram (20170131-20170212)

<p>In february 2017 a series of earthquakes affected the Biga Peninsula in Western Turkey. Over 350 buildings sustained extensive damage. The seismic events occurred at the intersection of the Kestanbol Fault and the Edremit Fault Zone. The Sentinel-1 TOPS co-seismic interferogram was generated with the ESA SNAP toolbox (http://step.esa.int/).</p> <p>S1A data were downloaded from the Sentinel-1 Scientific Data Hub: S1A_20170131-S1A_20170212 from ASCENDING orbit 131.</p> <p> </p

4D geometrical and structural analysis of ground ruptures related to 2016 earthquakes in Sibillini mountains (Central Italy)

3D multi-temporal reconstructions (4D) of the geometries and the kinematics of a portion of the 35 km coseismic surface ruptures related to 2016 Central Italy earthquakes are presented. The analysis integrates a traditional structural field survey with the data extracted from 3D point cloud models. These models were generated using a Structure-from-Motion (SfM) algorithms applied to georeferenced low-altitude aerial digital photos, both zenithal and oblique, acquired with small Unmanned Aerial Vehicles (UAV). Several comparisons were performed between data measured in the field and the same data detected on the point cloud models. The results show errors of a few cms, where models generally overestimate the real data. The coseismic ground ruptures typically show multiple overlapping scarps that can be divided into kinematic sets that occur throughout the width of the pre-existing SW dipping normal fault zones

Detection and Monitoring of Tunneling Induced Ground Movements Using Sentinel-1 SAR Interferometry

SAR interferometry is a powerful tool to obtain millimeter accuracy measurements of surface displacements. The Sentinel-1 satellite mission nowadays provides extensive spatial coverage, regular acquisitions and open availability. In this paper, we present an MT-InSAR analysis showing the spatial and temporal evolution of ground displacements arising from the construction of a 3.71 km overflow tunnel in Genoa, Italy. Underground tunneling can often modify the hydrological regime around an excavated area and might induce generalized surface subsidence phenomena due to pore pressure variations, especially under buildings. The tunnel was excavated beneath a densely urbanized area lying on upper Cretaceous marly limestone and Pliocene clays. Significant cumulative displacements up to 30 mm in the Line of Sight (LOS) direction were detected during the tunnel excavation. No displacements were recorded before until the middle of 2016. The Persistent Scatterers Interferometry (PSI) analysis reveals in high detail the areal subsidence, especially where the subsurface is characterized by clay and alluvial deposits as well as there is the presence of large building complexes. The time-series and the displacement rate cross-sections highlight a clear relation with the tunnel face advancement, responsible for the subsidence phenomena, which proceeded northward starting from the middle of 2016 to the end of 2017. The stabilization occurred in a range of five-six months from the beginning of each displacement phase. Due to the low subsidence ratio the ground settlements did not cause severe damages to the buildings

Sentinel-1 Interferometry and UAV Aerial Survey for Mapping Coseismic Ruptures: Mts. Sibillini vs. Mt. Etna Volcano

The survey and structural analysis of surface coseismic ruptures are essential tools for characterizing seismogenic structures. In this work, a procedure to survey coseismic ruptures using satellite interferometric synthetic aperture radar (InSAR) data, directing the survey using Unmanned Aerial Vehicles (UAV), is proposed together with a field validation of the results. The Sentinel-1 A/B Interferometric Wide (IW) Swath TOPSAR mode offers the possibility of acquiring images with a short revisit time. This huge amount of open data is extremely useful for geohazards monitoring, such as for earthquakes. Interferograms show the deformation field associated with earthquakes. Phase discontinuities appearing on wrapped interferograms or loss-of-coherence areas could represent small ground displacements associated with the fault’s ruptures. Low-altitude flight platforms such as UAV permit the acquisition of high resolution images and generate 3D spatial geolocalized clouds of data with centimeter-level accuracy. The generated topography maps and orthomosaic images are the direct products of this technology, allowing the possibility of analyzing geological structures from many viewpoints. We present two case studies. The first one is relative to the 2016 central Italian earthquakes, astride which the InSAR outcomes highlighted quite accurately the field displacement of extensional faults in the Mt. Vettore–M. Bove area. Here, the geological effect of the earthquake is represented by more than 35 km of ground ruptures with a complex pattern composed by subparallel and overlapping synthetic and antithetic fault splays. The second case is relative to the Mt. Etna earthquake of 26 December 2018, following which several ground ruptures were detected. The analysis of the unwrapped phase and the application of edge detector filtering and other discontinuity enhancers allowed the identification of a complex pattern of ground ruptures. In the Pennisi and Fiandaca areas different generation of ruptures can be distinguished, while previously unknown ruptures pertaining to the Acireale and Ragalna faults can be identify and analyzed

The seismogenic source of the 2018 December 26th earthquake (Mt. Etna, Italy): A shear zone in the unstable eastern flank of the volcano

The 2018 December 26th earthquake (MW = 4.9) at the south-eastern slope of Mt. Etna provides new insights for improving the knowledge of the kinematics of the eastern flank of the volcano. The earthquake was preceded by a seismic swarm on the upper southern-western sector of the volcano and by a short eruptive event in the summit area. The associated crustal deformation triggered seismic reactivation of tectonic structures in the eastern flank of the volcano. The seismogenic source has been localized along one of the segments cutting the south-eastern slope the volcanic edifice, the NW-SE trending Fiandaca Fault, one of the most active shear zone belonging to the upslope extension of the Timpe fault system. In the last centuries, all these faults have been the source of very shallow, low magnitude, but destructive earthquakes. In order to determine the response of the unstable eastern flank of Mt. Etna to the volcano-tectonic events, we applied a multidisciplinary approach based on: i) analysis of historical and instrumental seismicity; ii) mapping of coseismic fracturing, iii) analysis of GPS and InSAR data. This study allows to better define the seismotectonic framework of the shear zone occurring in the eastern flank of Mt. Etna, framing it in the seismogenic belt extending as far as the Ionian offshore

Tn (Tidal notches) in the western Adriatic coast as markers of local coastal stability during late Holocene.

none12noneStefano Furlani, Daniela Piacentini, Francesco Troiani, Sara Biolchi, Matteo Roccheggiani, Andrea Tamburini, Emanuela Tirincanti, Valeria Vaccher, Fabrizio Antonioli, Stefano Devoto, Olivia Nesci, Marco MenichettiFurlani, Stefano; Piacentini, Daniela; Troiani, Francesco; Biolchi, Sara; Roccheggiani, Matteo; Tamburini, Andrea; Tirincanti, Emanuela; Vaccher, Valeria; Antonioli, Fabrizio; Devoto, Stefano; Nesci, Olivia; Menichetti, Marc