TY  - JOUR
A1  - Soumaya, Abdelkader
A1  - Ben Ayed, Noureddine
A1  - Rajabi, Mojtaba
A1  - Meghraoui, Mustapha
A1  - Delvaux, Damien
A1  - Kadri, Ali
A1  - Ziegler, Moritz
A1  - Maouche, Said
A1  - Braham, Ahmed
T1  - Active Faulting Geometry and Stress Pattern Near Complex Strike-Slip Systems Along the Maghreb Region
BT  - Constraints on Active Convergence in the Western Mediterranean
JF  - Tectonics
N2  - The Maghreb region (from Tunisia to Gibraltar) is a key area in the western Mediterranean to study the active tectonics and stress pattern across the Africa-Eurasia convergent plate boundary. In the present study, we compile comprehensive data set of well-constrained crustal stress indicators (from single focal mechanism solutions, formal inversion of focal mechanism solutions, and young geologic fault slip data) based on our and published data analyses. Stress inversion of focal mechanisms reveals a first-order transpression-compatible stress field and a second-order spatial variation of tectonic regime across the Maghreb region, with a relatively stable S-Hmax orientation from east to west. Therefore, the present-day active contraction of the western Africa-Eurasia plate boundary is accommodated by (1) E-W strike-slip faulting with reverse component along the Eastern Tell and Saharan-Tunisian Atlas, (2) a predominantly NE trending thrust faulting with strike-slip component in the Western Tell part, and (3) a conjugate strike-slip faulting regime with normal component in the Alboran/Rif domain. This spatial variation of the present-day stress field and faulting regime is relatively in agreement with the inferred stress information from neotectonic features. According to existing and newly proposed structural models, we highlight the role of main geometrically complex shear zones in the present-day stress pattern of the Maghreb region. Then, different geometries of these major inherited strike-slip faults and its related fractures (V-shaped conjugate fractures, horsetail splays faults, and Riedel fractures) impose their component on the second- and third-order stress regimes. Neotectonic and smoothed present-day stress map (mean S-Hmax orientation) reveal that plate boundary forces acting on the Africa-Eurasia collisional plates control the long wavelength of the stress field pattern in the Maghreb. The current tectonic deformations and the upper crustal stress field in the study area are governed by the interplay of the oblique plate convergence (i.e., Africa-Eurasia), lithosphere-mantle interaction, and preexisting tectonic weakness zones.
KW  - Maghreb
KW  - strike-slip system
KW  - conjugate fractures
KW  - horsetail splays
KW  - active stress
KW  - tectonic regime
Y1  - 2018
U6  - https://doi.org/10.1029/2018TC004983
SN  - 0278-7407
SN  - 1944-9194
VL  - 37
IS  - 9
SP  - 3148
EP  - 3173
PB  - American Geophysical Union
CY  - Washington
ER  -