InSAR data as a field guide for mapping minor earthquake surface ruptures: Ground displacements along the Paganica Fault during the 6 April 2009 L'Aquila earthquake

Abstract

, a moderate earthquake (M w = 6.3; M l = 5.8) struck the Abruzzo region in central Italy, causing more than 300 fatalities and heavy damage to L'Aquila and surrounding villages. Coseismic surface effects have been thoroughly documented by timely field surveys as well as by remote sensing analyses of satellite images. The outstanding quality of geological, seismological, geodetic, and interferometric synthetic aperture radar (InSAR) information arguably represents the best ever data set made available immediately after a moderate seismic event. Based on this data set, we aim at testing the capability of coupled geological and InSAR data to map surface faulting patterns associated with moderate earthquakes. Coseismic ground ruptures have been mapped at a scale of 1:500 in the whole epicentral area. Traces of surface ruptures have been inferred from linear phase discontinuities identified in the interferogram. A very good agreement between the two methods resulted in the characterization of the main surface rupture along the Paganica fault. The same approach applied to ground ruptures hypothesized along other capable fault segments provided more questionable results. Thus, the combined field and InSAR approach appeared useful for detecting continuous surface ruptures exceeding 1 km in length and showing displacements greater than a few centimeters. These are the typical faulting parameters for moderate earthquakes (6.0 < M w < 6.5) in central Apennines. For continuous ground cracks shorter than a few hundred meters and/or that show displacements smaller than 1-2 cm, the described approach may be less helpful, most probably due to the limited resolution of the data.Citation: Guerrieri, L., et al. (2010), InSAR data as a field guide for mapping minor earthquake surface ruptures: Ground displacements along the Paganica Fault during the 6

Present kinematics of Central and Northern Italy from continuous GPS measurements

“…All coseismic displacements are compatible with those predicted by a shallow planar SW-dipping normal fault with a ∼0.5 to 0.6 m coseismic slip, proposed by various authors (Anzidei et al, 2009;Atzori et al, 2009;Walters et al, 2009Cheloni et al, 2010Guerrieri et al, 2010;Serpelloni et al, 2012) on the basis of the dislocation theory in an elastic half-space (Okada, 1985).…”

“…13.42 • ). The focal mechanism (Pondrelli et al, 2010), aftershock distribution (Chiarabba et al, 2009) and surface deformation (e.g., Anzidei et al, 2009;Atzori et al, 2009;Cheloni et al, 2010;Falcucci et al, 2009;Guerrieri et al, 2010) indicate that this shallow event occurred on a NW-SE trending SW-dipping normal fault, probably propagating to the surface at the Paganica fault.…”

Quaternary geology of the Middle Aterno Valley, 2009 L'Aquila earthquake area (Abruzzi Apennines, Italy)

“…Cinti et al, 2011;Galli, Giaccio, Messina, Peronace, & Zuppi, 2011;Gori et al, 2012;Improta et al, 2012;Moro et al, 2013). At the same time, despite this proliferation of investigations, (Blumetti, Guerrieri, & Vittori, 2013;Civico, Pucci, De Martini, & Pantosti, 2014;Galli et al, 2010;Giaccio et al, 2012;Guerrieri et al, 2010), these are limited from a long-term geological perspective.…”

Small-displacement linear surface ruptures of the 2016 Kumamoto earthquake sequence detected by ALOS-2 SAR interferometry

“…However, Fujiwara et al (2000a, b), Fukushima et al (2013), Guerrieri et al (2010), Nishimura et al (2008) and Wei et al (2011) reported that lineaments representing small displacements appear on interferograms, and Oskin et al (2012) reported that small displacements appear in differential LiDAR images.…”