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Assessing post‑pliocene deformation in a context of slow tectonic deformation: insights from paleoseismology, remote sensing and shallow geophysics in Provence, France Franck Thomas, et al. [full author details at the end of the article] Received: 8 May 2020 / Accepted: 28 September 2020 © Springer Nature B.V. 2020

Abstract The Provence region, located in the south-east of France, has experienced a few destructive earthquakes during the last centuries, such as the 1909 Lambesc earthquake or the 1509 and 1708 Manosque earthquakes. However, faults in the area experience slow slip rates ( 1.8 located in the vicinity of the fault system, the highest being MW = 2.8 in 1963. We can, however, cite two larger seismic events in the MDFS area during the 2010s, both included in the RéNASS (Réseau NAtional de Surveillance Sismique) database: the ML = 2.9 event 3  km from Manosque in 2010 and the ML = 3.3 event 11  km to the north of Manosque in 2012. The immediate surrounding of the TF is characterized by low-magnitude earthquakes, with only one event at MW > 2.4 recorded in the SI-Hex catalogue, despite the fact that this fault generated the 1909 Lambesc earthquake. Similarly, the Salon-Cavaillon fault is surrounded by earthquakes with MW  2.5 have been registered during the last 50 years, the largest one at MW = 3.1 in 1986.

2.4 Previous tectonic and paleoseismic investigations in Provence Paleoseismologic investigations extend the window of observation of a fault system from the last millennium to the late Quaternary. Various studies using this approach have been conducted in western Europe and France, such as in the Alps (Alasset 2005; Hyppolite et al. 2006; Sanchez et al. 2010), the Jura Mountains (Baize et al. 2002; De La Taille et al. 2015), the Pyrenees (Alasset and Meghraoui, 2005) and the Upper Rhine (Lemeille et al. 1999; Meghraoui et al. 2000). These studies were carried out to identify faults producing

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Natural Hazards

paleo-earthquakes during the Late Quaternary and to estimate their maximum magnitude and averaged fault slip rates. With this aim in view, the Neopal online catalogue records neotectonic and paleoseismological indices in France (www.neopa​l.net, e.g. Baize et  al. 2013), each assigned a quality attribute. In Provence, four paleoseismological events are listed as “certain” in the Neopal catalogue, two of them located on the MDFS and two others on the TF (see Fig. 1 for location). Trench studies in Provence mainly focus on these two structures because they correspond to the areas with the highest density of historic and instrumental seismicity. The MDFS has been the centre of various structural and paleoseismological studies (Cushing et  al. 2008; Guyonnet-Benaize et  al. 2015), most notably at La Brillanne and Valveranne. Concerning La Brillanne, a reverse fault parallel to the MDFS is visible on the western side of the Durance river and is compatible with the deformation pattern deduced from regional observations and focal mechanisms (Terrier 1991; Baize et  al. 2002). In Valvéranne, Ghaf