The Approach to Daesh in Tunisia: From Bardo to Ben Gardane, aYear of Terror

Starting from a descriptive analysis of the main attacks by Daesh in Tunisia, this article examines the nature and evolution of the terrorist organization in this North African country. Thus, it examines the characteristics and vicissitudes of the attack on the Bardo Museum in March 2015, the attack on the Susa beach in June 2015, the bombing of the Presidential Guard in November 2015 and, finally, the military offensive against the town of Ben Gardane in March 2016. In addition, it presents some previous facts that are relevant in this research, such as the important presence of Tunisian foreign fighters in Syria or Libya, and, in particular, the threat of Daesh in Libya to the Tunisian State

Strength of the Iberian intraplate lithosphere: Cenozoic deformations and seismicity

Previous studies about the strength of the lithosphere in the Iberia centre fail to resolve the depth of earthquakes because of the rheological uncertainties. Therefore, new contributions are considered (the crustal structure from a density model) and several parameters (tectonic regime, mantle rheology, strain rate) are checked in this paper to properly examine the role of lithospheric strength in the intraplate seismicity and the Cenozoic evolution. The strength distribution with depth, the integrated strength, the effective elastic thickness and the seismogenic thickness have been calculated by a finite element modelling of the lithosphere across the Central System mountain range and the bordering Duero and Madrid sedimentary basins. Only a dry mantle under strike-slip/extension and a strain rate of 10-15 s-1, or under extension and 10-16 s-1, causes a strong lithosphere. The integrated strength and the elastic thickness are lower in the mountain chain than in the basins. These anisotropies have been maintained since the Cenozoic and determine the mountain uplift and the biharmonic folding of the Iberian lithosphere during the Alpine deformations. The seismogenic thickness bounds the seismic activity in the upper–middle crust, and the decreasing crustal strength from the Duero Basin towards the Madrid Basin is related to a parallel increase in Plio–Quaternary deformations and seismicity. However, elasto–plastic modelling shows that current African–Eurasian convergence is resolved elastically or ductilely, which accounts for the low seismicity recorded in this region.