GNGTS 2013 - Atti del 32° Convegno Nazionale

soil condition at each site, studying their distributions (Sirovich and Pettenati, 2001, 2004; Pettenati and Sirovich, 2003, 2004). To this end different lithological and geophysical large- scale classifications were used, but none worked (Pettenati and Sirovich, 2007). No objective criteria for all the used sites were available in the present case, however. In this context, some Israeli colleagues, who read our studies on two Italian earthquakes in 1570 and 1694 (Sirovich et al. , 2013a, b), suggested us to attempt the intensity-based source inversion also of the event of 1927 using our KF technique. Tab. 1 – Epicentres of the 1927 earthquake proposed by various authors (and one secondary macroseismic effect supposedly connected to the epicentre). Reference Latitude [°] Longitude [°] Ben-Menahem et al. (1976) 32.2 35.5 Shapira et al. (1993) 31.6 35.4 many references a 32.0 35.5 Zohar and Marco (2012) b 31.8 35.5 Avni et al. (2002) 31.6 35.4 Doubtful Jordan damming c (Garstang, 1931) 32.0 d 35.5 d a ) 30 km north of Jericho, interpreted -on a qualitative basis- as a strike-slip rupture along the Dead Sea transform DST; according to Avni et al. (2002), most of these references relied on the recording of one only station (Ksara, Lebanon) and on the unreliable Jordan damming ‘evidence’ by Garstang (1931); b ) using only intensities; c ) unreliable, according to Avni et al. (2002); d ) approximate values. Tectonic context. The area of study is on the contact between the African and the Arabian plates, north of the Sinai sub-plate, along the Dead Sea Transform Fault extending Nward to the Amanos-Zagros section of the Eurasia-Africa-Arabia convergence zone. The tectonic interpretation of the area is not easy, also for political reasons, because the two sides of the Jordan Valley are for long not freely accessible. The pull-apart nature of the Dead Sea depression still is an unresolved questions. In short, as noticed by Devès et al. (2011), although most agree that the Dead Sea valleys are tectonic in origin, no one agrees on the processes that have led to its formation. The same authors notice a striking feature of the Red Sea-Galilee Lake allignement: there is an ~11.5° change of direction between the Jordan Valley (south of the Dead Sea) and the Araba Valley (north of it). This: i) precludes a uniform stress distribution in the region (as if the principal transform structure would be rectilinear); ii) causes still unknown stress distribution and, consequently, rupture mechanisms in the region. However, Devès et al. (2011) find that 65% of the deformation in the Dead Sea region can localise on kinematically stable through-going strike-slip faults (the DST; our comment) while the remaining ~35% has to remain distributed. If this holds, our preliminary source (Model 1 in Tab. 2) would belong to the remaining 35%. On the one hand, these authors specify that there are no clear normal faults along the valley flanks (unlike Carmel fault), such as in true rifts like Corinth or East Africa, but, on the other one, they comment on that there are no normal faults along the valleys flanks that could account for the 600 m depression of the Dead Sea. The work by Shamir (2006) is more encouraging for us, because it lets hope that our source be more compatible with the tectonics of the region from the Dead Sea to the area north of Jericho. He thinks that the late-phase (late Pliocene-early Pleistocene) asymmetrical shear zone of the DST is characterized also by a penetrative, bimodal (NW and NE) structural orientation pattern, reflected in earthquake focal mechanisms. Regarding the NE-oriented 125 GNGTS 2013 S essione 1.1