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

Balkis Samah Kohila,Soumaya Boussetta,Nejib Kallel,Laurent Dezileau,Tarek Melki

doi:10.5194/nhess-21-3645-2021

Balkis Samah Kohila, Soumaya Boussetta + Show 3 more

Open Access

https://doi.org/10.5194/nhess-21-3645-2021

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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.

Highlights

During the last century, coastal communities have become very vulnerable to many extreme events such as tsunamis, tropical storms, hurricanes, and floods (Chaumillon et al, 2017)
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 was applied to these cores. These cores were 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

Summary

Introduction

Coastal communities have become very vulnerable to many extreme events such as tsunamis, tropical storms, hurricanes, and floods (Chaumillon et al, 2017). One of the most destructive recorded meteorological events was Hurricane Katrina in Florida, in the United States, in 2005 It engenders more than USD 100 billion of damages, killed around 2000 people, and touched 90 000 square miles (233 098 km2) of the United States (Phadke, 2005). The 2004 Sumatra tsunami was associated with a megaearthquake with Mw 9.2 This tsunami has generated high waves up to 30 m and caused 250 000 deaths (Paris et al, 2010). This tsunami was considered the most hazardous event compared to other past catastrophic events that occurred in 1797 and 1833 on the coast of Sumatra island (Ahmadun et al, 2020)

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