Les trois dernières guerres ont laissé dans le sous-sol français des millions de tonnes de munitions non explosées (en anglais, unexploded ordnance ou UXO) qui constituent un risque pour l'homme et l'environnement. La géophysique et particulièrement les méthodes magnétiques offrent des solutions pour localiser et caractériser ces objets qui sont le plus souvent aimantés. Mon travail de thèse consiste d'abord à réaliser une synthèse bibliographique des méthodes de recherche d'UXO en détaillant en particulier la méthode magnétique. Le dispositif de cartographie magnétique multi-capteur conçu par I'EOST et utilisé pour la recherche d'UXO subit un certain nombre de défauts. Ainsi (i) la fabrication d'un nouveau numériseur, (ii) l'acquisition d'un nouveau système de géolocalisation plus complet et (iii) l'utilisation d'un capteur supplémentaire afin de corriger les variations temporelles du champ permettent d'améliorer la qualité de nos cartographies. De même la mesure à différentes altitudes nous permet de gérer au mieux le temps imparti et le niveau de détail que l'on souhaite obtenir. Selon l'approximation habituellement employée en méthodes potentielles, l'anomalie du champ magnétique est négligeable par rapport au champ magnétique régional. En parallèle du travail de terrain décrit précédemment, une étude plus poussée du dipôle m'a permis d'évaluer que cette approximation entraîne une erreur non négligeable pouvant atteindre 16% de l'anomalie. Cette différence se ressent aussi sur les résultats obtenus par inversion. J'ai pu de plus développer un algorithme utilisant la méthode d'Euler et réévaluer la méthode que l'on utilisait déjà auparavant, basée sur le signal analytique. Après comparaison des différentes méthodes d'inversion, cette dernière semble le mieux contraindre la cible. / Last three wars have left millions of tons of unexploded ordnance (UXO) in French subsoil. They put the population and the environment at risk. Geophysics and particularly the magnetic methods present some solutions to characterise and locate those generally magnetised objects. The multi-sensor magnetic cartography device designed at EOST has some faults. Consequently, (i) the production of a new digitizer, (ii) the acquisition of a new geo-spatial positioning system and (iii) the use of an extra sensor to correct the time-related variations of the magnetic field allow us to improve our cartography quality. Likewise, multi-altitude measurement allow us to optimise the time in relation to the wanted cartography definition. According to the approximation generally used in magnetism theory, the anomaly is insignificant compared to the regional magnetic field. At the same time as my previously described field work, a thorough study of the dipole theory, allowed me to evaluate that this approximation results in a non-negligible mistake reaching 16% of the anomaly. The inversion results are sensible to this mistake. Moreover, l've developed an algorithm based on Euler deconvolution and l've re-evaluated the method already used which is based on analytic signal. After I compared some of the inversion methods, the one based on the analytic signal seems to ascertain the better the object characteristics.

Remediation of unexploded ordnance (UXO) and prioritization of excavation procedures for archaeological artifacts using electromagnetic (EM) induction are studied in this dissertation. Lowering of the false alarm rates that require excavation and artifact excavation prioritization can reduce the costs associated with unnecessary procedures. Data were taken over 5 areas at the San Jacinto Battleground near Houston, Texas, using an EM-63 metal detection instrument. The areas were selected using the archaeological concepts of cultural and natural formation processes applied to what is thought to be areas that were involved in the 1836 Battle of San Jacinto. Innovative use of a Statistical Point Pattern Analysis (PPA) is employed to identify clustering of EM anomalies. The K-function uses point {x,y} data to look for possible clusters in relation to other points in the data set. The clusters once identified using K-function will be further examined for classification and prioritization using the Weighted K-function. The Weighted K-function uses a third variable such as millivolt values or time decay to aid in segregation and prioritization of anomalies present. Once the anomalies of interest are identified, their locations are determined using the Gi-Statistics Technique. The Gi*-Statistic uses the individual Cartesian{x, y} points as origin locations to establish a range of distances to other cluster points in the data set. The segregation and location of anomalies supplied by this analysis will have several benefits. Prioritization of excavations will narrow down what areas should be excavated first. Anomalies of interest can be located to guide excavation procedures within the areas surveyed. Knowing what anomalies are of greater importance than others will help to lower false alarm rates for UXO remediation or for archaeological artifact selection. Knowing significant anomaly location will reduce the number of excavations which will subsequently save time and money. The procedures and analyses presented here are an interdisciplinary compilation of geophysics, archaeology and statistical analysis brought together for the first time to examine problems associated with UXO remediation as well as archaeological artifact selection at historic battlegrounds using electromagnetic data.

The dominant liberal peacebuilding critiques tends to focus on ‘states’ and the failure of interventions in rebuilding them. Consequently, a standardised critique has emerged largely because the critics apply a broad brush across a diverse range of contexts, programmes, issues and activities as illustrated by the lack of scrutiny on mine action and emerging contexts such as Somaliland. The liberal peacebuilding critics critique the standardised ‘one size fits all approach’ employed by interveners, yet they take the same approach. I therefore argue for the need to broaden the critique to include other elements and contexts of peacebuilding. I demonstrate that as an intervention mine action has intrinsic peacebuilding potential. However, the way mine action is implemented both globally and in Somaliland reflects the same dominant characteristics of the liberal peacebuilding critique i.e.; it is externally led; uses technical and standardised formulaic approaches; disregards local context thus failing to secure local ownership. Attributes that the critics argue have led to the failure and/or limited success of peacebuilding interventions. I therefore contend with the critics and demonstrate how these attributes have contributed to the challenges of implementing mine action activities thereby limiting mine actions ‘peace-ability’ potential in Somaliland. However, beyond the implementation modalities there are other factors that further contribute to limiting this potential; these include the Sector Actors; the Somaliland context i.e. the historical and political context, and the perception of Somaliland people. Thus in conclusion I argue for a nuanced critique that acknowledges the challenging realities of implementing programmes in challenging post conflict environments.

This study addresses the need for improved risk assessment (RA) during explosive ordnance disposal (EOD) at sea by highlighting the environmental and operational complexities of handling unexploded ordnance (UXO) in the marine environment. It discusses the increasing demand for offshore EOD due to the construction of offshore wind parks and initiatives proactively addressing UXO dump sites. Conducting EOD work professionally and diligently to prevent accidents and environmental contamination will, hence, continue to be of paramount importance. In an effort to understand the RA tools that are available to EOD experts, this work reviews ten RA methods and identifies a methodological gap, thereby revealing the need for a new EOD RA method. Consequently, it introduces a novel method named the Risk Assessment Model for Unexploded underwater Military Munitions (RUMMs). This model is based on a directed graph and considers properties and aspects of the UXO, the environment, and the EOD procedure. RUMMs, which can be used during early EOD planning states or immediately before UXO handling, calculates the probability of an undesired detonation, the consequence of an undesired detonation, and the complexity of the EOD operation. The model is extensively explored by means of local sensitivity analysis and Monte Carlo simulation to demonstrate its reliability. Subsequently, RUMMs is tested with twenty EOD operations, which yield plausible model outputs that are in line with expectations and real-world decisions. The model's consistent and reproducible results, unaffected by fatigue or time pressure, add a new layer of reliability to EOD decision-making.:1 Introduction 1.1 Offshore UXO in a Multi-Use and Multiple Stressor Environment 1.2 Focus, Scope, and Purpose of this Dissertation 1.3 Research Hypotheses 1.4 Structure of the Dissertation 2 The Issue of Offshore Unexploded Ordnance 2.1 Background and Context 2.2 UXO Properties 2.3 Potential Effects of the Presence of UXO 2.4 Conclusion—The Case for Explosive Ordnance Disposal 3 Offshore Explosive Ordnance Disposal 3.1 EOD frameworks 3.2 EOD procedure According to the Selected Framework 3.3 EOD in Practice 3.4 Environmental Properties Affecting EOD 3.5 Conclusion—The Case for EOD Risk Assessment 4 Review of Risk Assessment Methodologies 4.1 Risk—A Brief Overview 4.2 Preparation of the Offshore UXO and EOD Risk Assessment Review 4.3 Offshore UXO Risk Assessment Review 4.4 Conclusion—The Case for a Novel Method for EOD RA 5 Development and Description of the EOD RA Model 5.1 Background of the EOD RA Model 5.2 Development Process of RUMMs 5.3 Undesired Events 5.4 Exceptions, Inherent Risk and Residual Risk 5.5 Risk Receptors 5.6 The Two Model Layouts 5.7 RUMMs Factors 5.8 Omitted Factors 5.9 Model Outputs 5.10 Other RUMMs Functionalities 5.11 Model Limitations 5.12 Conclusion—The Case for Model Exploration and Testing 6 Methodological Exploration and Application 6.1 Local Sensitivity Analysis 6.2 Monte Carlo Simulation 6.3 Application of RUMMs 6.4 Revision of the Gap Analysis 6.5 The Future of RUMMs 6.6 Conclusion—The Case for Real World Application 7 Conclusion 7.1 Recap of the Research Hypotheses 7.2 Outlook on RUMMs 7.3 Recommendations for UXO and EOD Research 7.4 RUMMs’ Response to Other Demands 7.5 RUMMs and the Way Forward in Offshore EOD

L’objectif de ce travail est d’améliorer la caractérisation des sources à l’origine d’anomalies magnétiques, par le biais de développements théoriques et expérimentaux. Pour des structures invariantes dans une direction horizontale (structures à 2D), l’idée de Nabighian (1972) a été généralisée, ce qui implique une nouvelle façon d’étudier les méthodes potentielles à 2D. Ces développements ont permis de proposer une nouvelle approche théorique et de nouvelles représentations dans le plan complexe des fonctions magnétiques. La deuxième approche de ce travail est expérimentale. Une étude y est faite par le biais de données et de cas synthétiques, afin d’estimer l’apport d’acquisitions magnétiques à différentes altitudes pour caractériser une source. Dans un troisième temps, les développements théoriques et expérimentaux sont mis en œuvre pour deux exemples : des anomalies magnétiques en domaine océanique de type Vine et Mathews et une cartographie pour l’archéologie. / Magnetic anomalies recorded outside bodies provide high quality information relative to buried structures. By using theoretical and experimental developments, this thesis aims to improve the characterization of the source inducing the magnetic anomaly. Firstly, some properties of three dimensional magnetic functions are presented, for example the presence of several maxima of the analytic signal operator (3D) is demonstrated. The Nabighian (1972) equation is generalized, which imply a new process to study potential method in two dimensions. These developments enable a new visualization of the anomaly in the complex field. The second approach is experimental. Synthetic cases are used to estimate the contribution of different configurations of magnetic data acquisitions at different altitudes to characterize the magnetic source. Theoretical and experimental developments are finally applied to two field examples: oceanic magnetic anomalies and archaeological magnetic prospection

The dominant liberal peacebuilding critiques tends to focus on ‘states’ and the failure of interventions in rebuilding them. Consequently, a standardised critique has emerged largely because the critics apply a broad brush across a diverse range of contexts, programmes, issues and activities as illustrated by the lack of scrutiny on mine action and emerging contexts such as Somaliland. The liberal peacebuilding critics critique the standardised ‘one size fits all approach’ employed by interveners, yet they take the same approach. I therefore argue for the need to broaden the critique to include other elements and contexts of peacebuilding. I demonstrate that as an intervention mine action has intrinsic peacebuilding potential. However, the way mine action is implemented both globally and in Somaliland reflects the same dominant characteristics of the liberal peacebuilding critique i.e.; it is externally led; uses technical and standardised formulaic approaches; disregards local context thus failing to secure local ownership. Attributes that the critics argue have led to the failure and/or limited success of peacebuilding interventions. I therefore contend with the critics and demonstrate how these attributes have contributed to the challenges of implementing mine action activities thereby limiting mine actions ‘peace-ability’ potential in Somaliland. However, beyond the implementation modalities there are other factors that further contribute to limiting this potential; these include the Sector Actors; the Somaliland context i.e. the historical and political context, and the perception of Somaliland people. Thus in conclusion I argue for a nuanced critique that acknowledges the challenging realities of implementing programmes in challenging post conflict environments.