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Seitenpfad:

Christoph Witt

Doktorand_innen

Gruppe: 

Marine Geotechnik

Telefon: 

+49 421 218-65669

E-Mail:

Raum: 

MARUM I, 2370

Christoph Witt

Homepage: LinkedIn

 

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

since 12/18

PhD stu­dent at MARUM, Uni­ver­si­ty of Bre­men, Germany

Working group: Marine Geotechnics

10/16 - 11/18

MSc Marine Geosciences, University of Bremen, Germany

Thesis: Stability and hydrogeology of the submarine slope off Nice, France

10/17 - 03/18

European Scientific Diver Course

10/13 - 09/16

BSc Geowissenschaften, University of Bremen, Germany

Thesis: Sediments of the Clarion-Clipperton Fracture Zone - primary and diagenetic signals

 


Expeditions

Year Vessel Cruise
2021 R/V L'EUROPE

FLUID3D-part3

Recovering and redeploying instruments at the Nice landslide airport scar [France]

2019 R/V L'EUROPE

FLUID3D-part1

Operations on the EMSO-LIGURE-NICE observatory network [France]

 2015  R/V SONNE (SO240)

FLUM - FLUid fluxes and Mn nodules 

Low-temperature fluid circulation at seamounts and hydrothermal pits: heat flow regime, impact on biogeochemical processes, and its potential influence on the occurrence and composition of manganese nodules in the equatorial eastern Pacific [Mexico]

 

 

Publications & Conference Posters

2021

Garziglia, S., Sultan, N., Thomas, Y., Ker, S., Marsset, B., Bompais, X., Woerther, P., Witt, C., Kopf, A. & Apparioul R. (2021). Assessing spatiotemporal variability of free gas in surficial cohesive sediments using tidal pressure fluctuations. Journal of Geophysical Research: Earth Surface, 126, e2021JF006131. https://doi. org/10.1029/2021JF006131

2020

Sultan, N., Garziglia, S., Bompais, X., Woerther, P., Witt, C., Kopf, A., & Migeon, S. (2020). Transient Groundwater Flow Through a Coastal Confined Aquifer and Its Impact on Nearshore Submarine Slope Instability. Journal of Geophysical Research: Earth Surface, 125(9), e2020JF005654. doi:10.1029/2020JF005654

2019

Witt, C., Garziglia, S., Migeon, S., Sultan, N., Wenau, S., & Kopf, A. (2019). Hydrogeology of the submarine slope off Nice, France. Poster Abstract, ICYMARE Bremen 2019, 24-27 September 2019

2017

Kasten, S., Versteegh, G., Koschinsky, A., Villinger, H., Dohrmann, I., Filsmair, C., Fronzek, J., Hartmann, J., Kleint, C., Preuss, I., Ritter, S., & Kuhn, T. (2017). Widespread diffusion of oxygen from oceanic crust into overlying sediments in the NE Pacific Ocean – early diagenetic consequences and significance for biogeochemical cycles (RV SONNE SO240). Poster Abstract, Goldschmidt Conference Paris 2017, 13-18 August 2017