Using Seismic Attributes in seismotectonic research: an application to the Norcia's Mw = 6.5 earthquake (30th October 2016) in Central Italy

Abstract

In seismotectonic studies, seismic reflection data are a powerful tool to unravel the complex deep architecture of 12 active faults. Such tectonic structures are usually mapped at surface through traditional geological surveying whilst seismic 13 reflection data may help to trace their continuation from the near-surface down to hypocentral depth. In this study, we 14 propose the application of the seismic attributes technique, commonly used in seismic reflection exploration by oil industry, 15 to seismotectonic research for the first time. The study area is a geologically complex region of Central Italy, recently struck 16 by a long-lasting seismic sequence including a Mw 6.5 main-shock. A seismic reflection data-set consisting of three vintage 17 seismic profiles, currently the only available across the epicentral zone, constitutes a singular opportunity to attempt a 18 seismic attribute analysis. This analysis resulted in peculiar seismic signatures which generally correlate with the exposed 19 surface geologic features, and also confirming the presence of other debated structures. These results are critical, because 20 provide information also on the relatively deep structural setting, mapping a prominent, high amplitude regional reflector 21 that marks the top basement, interpreted as important rheological boundary. Complex patterns of high-angle discontinuities 22 crossing the reflectors have been also identified. These dipping fabrics are interpreted as the expression of fault zones, 23 belonging to the active normal fault systems responsible for the seismicity of the region. This work demonstrates that 24 seismic attribute analysis, even if used on low-quality vintage 2D data, may contribute to improve the subsurface geological 25 interpretation of areas characterized by high seismic potential. 26 Introduction 27Studying the connections between the earthquakes and the faults to which they are associated is a primary assignment of 28 seismotectonics (Allen et al., 1965; Schwartz and Coppersmith, 1984). Clearly, this is not an easy task: it is in fact generally 29 complex to fill the gap between the exposed geology including the active "geological faults" mapped by the geologists and 30 https://doi.

Workflow of Digital Field Mapping and Drone-Aided Survey for the Identification and Characterization of Capable Faults: The Case of a Normal Fault System in the Monte Nerone Area (Northern Apennines, Italy)

“…Surface and deep reflection seismic data (CROP 03; [18,75]) crossing the mountain belt very close to the study area and the distribution of the epicenters [61] provide indications similar to those reported by various authors [3,[27][28][29][76][77][78][79] for the southernmost areas shaken by recent earthquakes. In our case, the evidence of normal faulting on the surface could be related to deep stretching, with negative inversion of thrusts, as demonstrated in areas further south [80][81][82][83].…”

High‐Resolution Seismic Imaging of Fault‐Controlled Basins: A Case Study From the 2009 Mw 6.1 Central Italy Earthquake

“…With the purpose of assisting the structural interpretation we computed the "energy" and "similarity" attributes on the post-stack data (Figures 4-6) using dGB Earth Sciences' OpendTect Pro ® . Seismic attributes, which are a common tool in hydrocarbon exploration, have been also used in recent years to improve detection of seismogenic faults in complex onshore crustal settings (see Bruno et al, 2017Bruno et al, , 2019Ercoli et al, 2020). "Similarity" is a typical discontinuity attribute that returns trace-to-trace similarity properties in post-stack data (Marfurt et al, 1998).…”

“…We used up‐to‐date processing and interpretation techniques that are standard for hydrocarbon exploration but not very often seen in shallow onshore exploration. For instance, to improve the seismic interpretation, we merged classic interpretation methods with seismic attributes and seismic impedance inversion, which are not yet a typical approach in high‐resolution shallow imaging of faults, especially in intramontane settings (e.g., Ercoli et al., 2020). These seismic reflection profiles, here presented for the first time, provide subsurface structural constraints to improve our knowledge about the long‐term basin evolution.…”

Ground-penetrating radar signature of Quaternary faulting: a study from the Mt. Pollino region, southern Apennines, Italy

“…Vettore area (central Apennines) during the 2016-2017 seismic sequence (Chiaraluce et al, 2017;Barchi et al, 2021 and references therein). Following the extensive coseismic ruptures mainly generated by the M w = 6.5 "Norcia" mainshock (Villani et al, 2018;Brozzetti et al, 2019;Testa et al, 2019), this area is currently an ideal laboratory for many conventional and innovative geoscience disciplines and applications (e.g., Xu et al, 2017;Porreca et al, 2018;Brozzetti et al, 2020;Cirillo, 2020;Ferrario et al, 2018;Ercoli et al, 2020;Michele et al, 2020;Porreca et al, 2020;Ferrarini et al, 2021;Pucci et al, 2021;Sapia et al, 2021;Villani et al, 2021). In fact, although the area is characterized by a complex alignment of normal faults, no important earthquakes were reported over the past ∼ 1500 years before this seismic crisis (Cinti et al, 2019;Galli et al, 2019Galli et al, , 2020.…”