NUMERICAL SIMULATION OF TSUNAMI HAZARDS IN SOUTH ATLANTIC COAST: CASE OF THE CITY OF AGADIR – MOROCCO: PRELIMINARY RESULT

The coastal zone is a highly complex area because of its location at the interface between land and sea and as a preferred location for many forms of development. A mega tsunami from the Canary Islands will hit not only the Atlantic coasts of Morocco, but also Spain, Portugal, Great Britain and even reach US shores.A slight earthquake or possible volcanic eruption can trigger one of the most violent natural disasters in history. Indeed, according to Steven Ward and Simon Day (2001) the west flank of the Cumbre Vieja volcano, located on the island of Palma is unstable and could, as a result of a future eruption, collapse into the ocean. It would be in the worst scenario of a huge piece of 25 km long, 15 wide and 1,400 meters thick that would come off, a total of 500 cubic kilometers of land and rocks. This wave could reach 50 meters of height, once arrived on the Moroccan coasts. In this study, a numerical inundation and vulnerability models are used to identify the location and nature of current and future hazards and risk on the Moroccan coast to better understand the tsunami hazard and vulnerability along the Moroccan coast. We have worked on the correction of coastlines from satellite imagery on Google Earth and the digitization of bathymetric and topographic maps, in order to create digital elevation models (DEM). We have also studied the vulnerability assessment of the buildings by using the BTV model (Building Tsunami Vulnerability) such as a combination of tsunami inundation numerical modelling, field survey data and geographic information system.

Taxonomy of the North Moroccan and Iberian species of the subgenus Amblypteraca (Coleoptera: Tenebrionidae: Pimeliinae: Pimelia)

The subgenus Amblypteraca Mas-Peinado, Buckley, Ruiz & García-París, 2018 of Pimelia Fabricius, 1775, is restricted to the southern Iberian Peninsula and western Maghreb (northern and western Morocco). The distribution of Amblypteraca throughout the African-European edges overlaps largely with the geographic range of the subgenus Amblyptera, which is sister to the clade grouping subgenera Amblypteraca and Ecphoroma Solier, 1836. Delimiting species boundaries in the speciose genus Pimelia is often challenging, and the taxonomic status of some groups within the aforementioned subgenera is still a matter of debate. Here, we aim to stabilize some of the available names in Amblypteraca, and to correct some previous misidentifications. For that purpose, we discuss the composition and taxonomic structure within Amblypteraca by (i) assessing the phylogenetic congruence between mitochondrial and nuclear markers, and (ii) examining external morphological traits in 568 Amblypteraca specimens under the light of the phylogenetic hypotheses proposed here. Based on our results, Amblypteraca consists of three species: P. rotundipennis Kraatz, 1865, P. fairmairii Kraatz, 1865 and P. chrysomeloides Pallas, 1781. Both molecular and morphological data revealed four lineages within P. chrysomeloides: P. chrysomeloides chrysomeloides, distributed on both sides of the Strait of Gibraltar; P. chrysomeloides fornicata Herbst, 1799 from Portugal (Troia region); P. chrysomeloides bathyglypta Antoine, 1949, restricted to a narrow strip between Larache and Arbaoua (northern atlantic Moroccan coast), and P. chrysomeloides subris Koch, 1941 from Kenitra-La Mamora forest (Morocco). We designate a neotype of Tenebrio chrysomeloides Pallas, 1781 and propose the synonymy of P. chrysomeloides (Pallas, 1781) = P. obesa Solier, 1836 syn. n. Pimelia tristis Haag-Rutenberg, 1875, previously misidentified and included in Amblypteraca, is now transferred back to Amblyptera. Further studies with ad hoc sampling designs and analytical tools would be in need to delimit the exact geographic ranges of these taxa, and to analyse the patterns of diversity within and among species and subspecies.

Age, Growth and Ovarian Histology of Sardinella aurita (Valenciennes, 1847) in the South of Atlantic Moroccan Coast

Otoliths reading and length frequency distribution were used for age determination and growth estimation of Sardinella aurita (round sardinella) stock of Southern Atlantic coast of Morocco. Both otoliths' method for age determination and Bhattacharya’s method for length frequency analysis showed five age groups. The growth performance index revealed that there is significant accordance among method of length frequency distribution and otoliths reading for stock assessment studies of Sardinella aurita stock in the south of Morocco. The microscopic observation of female gonads using histology method was investigated for the first time in our study area and confirms the presence of five principal stages of ovary of sardinella aurita: immature, maturing virgin and recovering spent, mature (or pre-spawning phase), spawning, post-spawning or spent. In addition, our results of the fecundity showed that the mean relative fecundity obtained is estimated at 193 ± 98 oocytes/g which is lower compared to those obtained in other areas in the Atlantic coast.

The Western Alboran Gyre: An Analysis of Its Properties and Its Exchange with Surrounding Water

One of the largest and most persistent features in the Alboran Sea is the Western Alboran Gyre (WAG), an anticyclonic recirculation bounded by the Atlantic Jet (AJ) to the north and the Moroccan coast to the south. Eulerian budgets from several months of a high-resolution model run are used to examine the exchange of water across the Eulerian WAG’s boundary and the processes affecting the salinity, temperature, and vorticity of the WAG. The volume transport across the sides of the WAG is found to be related to vertical isopycnal movement at the base of the gyre. Advection is found to drive a decay in the salinity minimum and anticyclonic vorticity of the Eulerian WAG. Given the large contributions of advection, a Lagrangian analysis is performed, revealing geometric aspects of the exchange that are hidden in an Eulerian view. In particular, stable and unstable manifolds identify a stirring region around the outer reaches of the gyre where water is exchanged with the WAG on a time scale of weeks. Its complement is an inner core that expands with depth and exchanges water with its surroundings on much longer time scales. The 3D evolution of one parcel, or lobe, of water as it enters the WAG is also described, identifying a general Lagrangian subduction pathway.