Shallow subsurface geology and seismic microzonation in a deep continental basin. The Avezzano Town, Fucino basin (central Italy)

Abstract

Abstract. 10We present detailed geological investigations aimed at the reconstruction of the shallow subsurface geology, and associated local seismic hazard, of the Avezzano town in the Quaternary Fucino basin (central Apennines). This work showsa basic (Level 1) seismic microzonation (SM) of the Avezzano town, focusing the attention on geologic constraints. We also discuss some methodological procedures of SM.Level 1 SM involves a reconstruction of the subsurface geological model achieved by a multidisciplinary approach 15 synthesized in two main thematic maps and geologic sections. The first map, containing essential geologic information, is formed by overlapping layers (geological units, litho-technical units, and geomorphological/structural features). The second map is a summary map, easily accessible to non-geologist earthquake scientists/technicians, which synthesizes surface geology, subsurface data and resonance frequencies into homogeneous microzones. The two maps are tools for land and urban planning. 20The Avezzano area provides a case study of shallow subsurface geology and site effects in a deep continental basin environment, and is of potential interest for similar geologic contexts worldwide. Within the investigated area, almost all the possible earthquake-induced effects can occur, such as a) stratigraphic amplifications in a wide range of resonance frequencies (from 0.4 to >10 Hz); b) liquefaction; c) coseismic surface faulting; d) basin-edge effects; and e) slope instability. 25

Basement Mapping of the Fucino Basin in Central Italy by ITRESC Modeling of Gravity Data

“…In the case of the Fucino Plain, EHD map analysis demonstrated its effectiveness by considering derivatives of the gravity potential from the second up to the fifth order (Figure 3). Such an optimal EHD tuning revealed trends of maxima, confirming the presence of several structural lineaments recognized or hypothesized as faults in previous studies (e.g., [2,9,18,19]. The faults bordering the Fucino Basin and, in particular, the Luco fault (western side), the Tre Monti fault (northern side), and the Pescina-Cerchio fault (eastern side) can be clearly identified (Figure 3).…”

“…The latter of these played an important role in the early evolution of the basin [16,17]. Within the basin, well and seismic reflection data [2,5] identified the Trasacco and Luco dei Marsi faults as the synthetic and antithetic splays of the Fucino main fault system [18,19]. A recent study [10] proposed more complicated fault architecture, assigning the features of a dual polarity half-graben to the Fucino basin.…”

“…The recent activity of the San Benedetto master fault is testified by the displacement and tilting of lacustrine formations and slope deposit sequences, the progressive offset of young sediments along Holocene normal fault scarps, the observations of coseismic surface faulting of the 13 January 1915, I = XI MCS Avezzano earthquake, and by trench investigations with related paleosismological studies. These data demonstrate that the SW-dipping San Benedetto master fault and its prolongation along the Magnola SSW-dipping fault are responsible for the 1915 earthquake producing a total surface rupture length of about 38 km [19][20][21][22][23][24][25][26].…”

Testing normal fault growth models by seismic stratigraphic architecture: The case of the Pliocene‐Quaternary Fucino Basin (Central Apennines, Italy)

“…The Fucino Basin itself has been infilled by >1,000 m of Pliocene-Recent continental clastic succession, mostly buried below the present-day topographic surface (Patacca et al 2008). None of the wells drilled to date reached depths greater than 200 m (Boncio et al, 2016;Cavinato et al, 2002;Di Naccio et al, 2020;Giaccio et al, 2017 -Figure 3) and sonic or checkshot data were not collected and are unavailable at these shallow and deeper depths. Some of the Pliocene-Pleistocene Fucino units, however, are thought to have been uplifted and exposed in terraces, particularly towards the northern and north-eastern periphery of the Fucino Basin (Figures 2b and 4; Messina, 1996).…”

New deep electrical resistivity tomography in the High Agri Valley basin (Basilicata, Southern Italy)

“…Caputo et al 2003). Several recent works focus on geophysical survey for deep geological and tectonic quaternary basin characterization (Boncio et al 2016;T€ un et al 2016;Civico et al 2017;Mekkawi et al 2017;Nocentini et al 2017;Onnis et al 2017). Furthermore, most recently reflection seismic and magnetotelluric surveys provide high-resolution images of fault systems (Improta et al 2017(Improta et al 2010Balasco et al 2015;Beckers et al 2015;Beilecke et al 2016;Beka et al 2017;Karaş et al 2017;Buttinelli et al 2016) giving a relevant support to seismologists and structural geologists.…”