Review article: Extreme marine events revealed by lagoonal sedimentary records in Ghar El Melh during the last 2500 years in the northeast of Tunisia

Abstract

Abstract. The Tunisian coast has been affected in the past by many events of extreme marine submersion (storms and tsunamis). A high-resolution study along two sediment cores taken from the lagoon of Ghar El Meleh was performed to identify the different paleoextreme events and to reconstruct the paleoenvironmental changes in the northeastern part of Tunisia during the Late Holocene. A very high-resolution sedimentological analysis (granulometric and geochemical) was applied to these cores. These cores were also dated with isotopic techniques (137Cs, 210Pbex, 14C), and the outcomes reveal five phases of paleoenvironmental changes in this lagoonal complex and identify two sediment layers that are in connection with two major historical marine submersion events. The first layer is mentioned as E1 and seems to fit with the great tsunami of 365 cal CE. This event was marked by an increase in the coarse sediment, and it is correlated for the first time with the immersed city of Neapolis in the northern Gulf of Hammamet discovered in 2017 by the same tsunamis of 365 cal CE. The other sandy layer, referred to as E2, was dated from 1690 to 1760 cal CE and is marked by one specific sedimentological layer attributed to a marine submersion event. This layer could be associated with the 1693 tsunami event in southern Italy or an increase in extreme storm events.

Assessment of Run-Up Height and Arrival Time of 365 AD Tsunami at Lampedusa Island, Italy

“…Table 3 presents important information on the arrival time and maximum run-up height in the first and second run-up phases at each observation location. The simulation of the 365 AD tsunami wave propagation in Lampedusa reinforces previous research that stated the impact of the 365 AD tsunami could reach Tunisia and Libya [10,12,30,31]. Tunisia is geographically located west of Lampedusa and farther from the epicenter of the 365 AD earthquake in the Western Hellenic Arc than the distance between the western Hellenic Arc and Lampedusa.…”

“…Therefore, considering that the wave propagation of the 365 AD tsunami extended to the east coast of Tunisia and the north coast of Libya, the 365 AD tsunami simulation, which suggests that the maximum run-up height at Lampedusa exceeded 1 m, is reliable. However, a definitive forecast of the maximum run-up height at Lampedusa requires support from evidence of tsunami deposits, as conducted by Kohila et al [31] in northeastern Tunisia.…”