43. Jimenez-Munt, I., P. Bird, and M. Fernandez (2001) Thin-shell modeling of neotectonics in the Azores-Gibraltar region, Geophys. Res. Lett., 28, no. 6, 1083-1086.
Abstract. We applied the thin-shell approach to study the neotectonics of the Africa/Eurasia plate boundary in the Azores-Gibraltar region. The plate boundary consists of a simple fault system running from Azores to the Gorringe Bank where it branches along the Betics and Rif-Tell thrust fronts. Major faults in west Iberia and NW Africa have been also incorporated. Results are compared with seismic strain rates, slip rates and stress orientations. The best friction coefficient is 0.1-0.15 meaning that the plate-boundary is about four times weaker than the adjacent lithosphere. The largest slip rates (>1.5 mm/yr) are obtained along the Gloria fault (strike-slip), and the Betic (transpressive) and Rif-Tell (compressive) thrust systems. Whereas the tectonic activity in the Atlas region is comparable to that obtained along the plate boundary, the slip rates in the west Iberia fault systems are one order of magnitude less.
P.S.Two parallel studies of this region were conducted with different modeling programs. This study used the SHELLS F-E program of Peter Bird. To compare to results with the UHURU F-D program by Ivone Jimenez-Munt, see paper #44. P. Bird, 2001.10.11
ÝFig. 1 - Zone of study, modeled faults, boundary conditions and mesh.
ÝFig. 2 - Mean stress azimuth error and seismic correlation for different fault frictions. Ideally, both curves would have maxima at the same value of fault friction, but they do not. The grey strip indicates the best compromise values for the fault friction.
ÝFig. 3 - Predicted scalar strain rates and fault slip rates from the best thin-shell model. White points are epicenters from the ISC catalog.
ÝFig. 4 - Most-compressive horizontal principal stress directions from the best thin-shell model, compared to data from the World Stress Map. Color indicates stress regime.