Application of Automated Throw Backstripping Method to Characterize Recent Faulting Activity Migration in the Al Hoceima Bay (Northeast Morocco): Geodynamic Implications

Abstract

Automation of the throw backstripping method has proven to be an effective tool for the determination of the evolution of tectonic activity in wide fault zones. This method has been applied to the Al Hoceima Bay (southwesternmost Mediterranean, Alboran Sea) for a time period covering the last 280 kyr on 672 faults imaged on 265 high-resolution seismic reflection profiles. This area was affected by major earthquakes and corresponds to a transtensional basin deformed by growth faults. The automated application of throw backstripping allowed for a faster deciphering of the migration of tectonic activity. Results show a westward migration of the deformation with quickly increasing deformation rates in the most recent time frames near Al Hoceima, one of the most populated cities. This migration is in agreement with the current seismicity, the GPS data, and recent brittle deformation data. Vertical throw rates of up to 0.47 mm/year have been calculated, for the most recent time periods, in segments of the Bokkoya fault zone. The westward migration of the deformation fits with the reconstruction suggested by the westernmost Mediterranean geodynamic models during the Pleistocene epoch, and it might be the consequence of the interaction between the northwest (NW) movement of the South Alboran indenter and the back Rif south-westward displacement. The highly accurate constraints of the evolution of the tectonic activity offered by this automation will substantially improve the seismic hazard assessment.

Lithostratigraphic analysis and characterization of the upper miocene deformation of the Beni Bou Ifroure massif (Jbel Harcha Unit) eastern Rif Morocco

“…These fault structures are also described on a smaller scale in the Lias carbonate masses where they are accompanied by lateral displacement of the massive compartments. Moreover, the operation of these dextral faults N120 is combined with other less important senestial sliding faults N25 and N45 that are part of the same family of faults affecting the Albran Sea such as the Yusuf fault [17,18], and the Idrissi fault [19,20].…”

The Neotectonic Deformation of the Eastern Rif Foreland (Morocco): New Insights from Morphostructural Analysis

“…The late N120 • E dextral and N025 • E sinistral structures characterising the Messinian episode may be correlated with the Yusuf Fault (N120 • E dextral) of the Alboran Sea [73,74] and that of Al Idrissi (N025 • E sinistral) [75][76][77][78].…”

Urban planning characterization based on earthquake parameters for development: Case of the city of Al Hoceima, Morocco

“…Geologically, the area of Al Hoceima is the most unstable and risky in Morocco because of the complex situation in the borders between the two plates, Eurasia and Africa, blocked between two major faults, the fault of El Jebha N70 [12] and the fault of Nekor N50 [14]. The geological context of the Al Hoceima region is further influenced by the presence of several fault systems, including the Al Hoceima and Kebdana faults, which have been identified as potential sources of seismic activity [21]. These faults exhibit various degrees of activity and have been associated with historical seismic events in the region [18].…”