Witt, Christoph

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ORCID: 0000-0003-4727-9187

Introduction

Nice (France) and the Côte d’Azur in general is a highly populated and touristy region where shoreline protection and safety are of the utmost importance. Sadly, the Nice area is not only famous for its pristine beaches but also for the catastrophic tsunamigenic submarine landslide that took place in October 1979, causing several casualties as well as damages to on- and offshore infrastructure. A combination of several triggers such as high precipitation prior the failure and the resulting pore pressure increase in the Nice Slope as well as the anthropogenic influence due to overloaded sediments as a function of marine constructions were made responsible for the collapse of the narrow shelf south of the airport. Ever since, many national and European studies have been conducted in order to better understand trigger mechanisms for slope failure and the likelihood of reoccurrence of such an event in the near future. Nevertheless, the processes prevailing and causing the initial failure are still poorly understood.

Project description

During my 3-year PhD position at MARUM I will be working in the “MODAL” project in close collaboration with the French Research Institute for Exploitation of the Sea (IFREMER) and the Géoazur. The main scientific objective of this ongoing project is to monitor seafloor deformation and assessing landslide hazards associated with fluid pressures at the Nice Slope (France).

The topic of my study circles around the key-objectives of this project. In the beginning of my study the link between precipitation and groundwater charging on one hand, and fluid pressure build-up and strain in the sub-seafloor on the other hand will be unraveled. Here, pore pressure data recorded over the last 13 years by 14 piezometers installed off the coast of the Nice airport will be analyzed. A specific and unique behavior characterized by sudden variations associated with fluid fluxes (and potentially other drivers) will be the main scientific objective in the first manuscript. In parallel, geotechnical testing on core samples will be carried out to simulate some of the effects measured in situ, e.g. earthquake tremor or aching owing to freshened fluids. Further creep tests will be performed using an oedometer. As a final task, some of the in situ and laboratory results will be taken into numerical simulations to predict failure conditions and shed light on future hazard potential in the Nice area.

Curriculum Vitae

Expeditions

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