Sea Tech Week : Underwater explosions (ENSTA session)
As part of Sea Tech Week 2026, an international event dedicated to marine science and technology, ENSTA will host an oral session on underwater explosions on Wednesday, October 7, from 9:30 a.m. to 12:00 p.m. The session will feature five presentations by international experts on this topic.
Session Schedule
The session "Underwater Explosions: Technical, Operational and Environmental Requirements", that will be held the 7th of october from 9h30 to 12h00 will address underwater explosions conducted in the marine environment for technical or operational purposes, such as maritime works or the neutralization of historical munitions. These activities raise significant technical, operational, and environmental challenges, including safety considerations, regulatory constraints, environmental impact assessment, and mitigation strategies.
Participants
Dr KICINSKI Radoslaw (Poland) : Nord Stream – How an Underwater Explosion Destroys Subsea Infrastructure
The presentation will discuss the Nord Stream explosions as a real-world case study, illustrating how an underwater explosion affects subsea structures. Based on publicly available data and engineering analysis, it will examine how the shock wave, seabed interaction, and local environmental conditions may have contributed to pipeline failure. The talk will also highlight that the consequences of such an event extend beyond the structure itself, affecting the surrounding marine environment and living organisms within the impact zone.
Dr Sole Marta Carbonell (Spain) : Article Motion and Pressure comparative effects on Marine Invertebrates using Aquavib
Scientific awareness is rising towards sea invertebrates' sensitivity to the particle motion component of the sound field. Under the SATURN EU-funded interdisciplinary research project, an experimental laboratory setup was developed: the AquaVib, a transparent acoustic chamber equipped with sound pressure, particle acceleration, dissolved oxygen, and temperature sensors, enclosed at both ends by a pair of 1 kN-electrody-namic (ED) shakers, capable to reproduce low-frequency sounds.
We use the AquaVib on three separate projects. In the Saturn project, we conducted ship URN exposure ex-periments on three groups of marine invertebrate species across a range of K-to-P energy ratios. In the Dia-phonia project, we carried out similar experiments using pile-driving sound. Currently, within the Seasounds project, we are studying the same effects caused by UXO sounds.
Prof. Sam Clarke (England) : Fragmentation Analysis for Underwater Ordnance Disposal
Explosive weapons may cause damage through both blast loading and fragmentation of their casings. Although air-detonated ordnance has been extensively studied, fragmentation hazards from underwater munitions remain underexplored, and therefore no standardised procedure exists to calculate safe standoff distances as a function of depth and charge mass in naval environments. This significantly hampers the safety planning process for underwater explosives ordnance disposal activities. Building on prior laboratory investigations of underwater fragmentation, this study extends the analysis toward full-scale applicability by estimating maximum fragmentation ranges and applying injury-criteria models to assess associated hazard limits. A series of well-controlled small-scale experiments compared cased explosive charges detonated in air and at varying submersion depths. Three casing configurations were tested to quantify the influence of depth and casing configuration type on fragment generation, in-flight behaviour, and size–velocity distributions. High-speed videography and in-situ witness panels were utilised to track fragmentation post-detonation and estimate velocities during flight and after impact. An in-house analysis code with optical and panel data was developed to compute fragment trajectories, maximum ranges, and soft-tissue penetration probabilities using established injury thresholds. Results indicate a pronounced reduction in fragment count, velocity and launch angle with increasing submersion depth, producing substantially shorter predicted penetration distances for all tested submerged charges.
Dr Samuel ETIENNE (France) : Propagation des ondes sismo-acoustiques associées au déminage en eaux peu profondes de munitions historiques
The French Navy routinely secures the French coastline and seabed through the controlled countermining of submerged or buried historical munitions (UXOs). Recent studies, such as the ANR ASTRID POSA project (2016–2019), have shown that the propagation of seismo-acoustic waves generated by shallow-water underwater explosions is highly complex and depends on seabed properties, bathymetry, and detonation conditions. Building on these findings, the ongoing RAPID MAESTRIA project (2025–2029) aims to improve our understanding of the environmental impacts of countermining operations on both terrestrial and marine environments by combining numerical modeling with in situ data collected in representative settings. Its objective is to develop advanced predictive tools and decision-support capabilities to better assess and mitigate the environmental impacts of countermining activities.
Dr Jérémie TARTIERE (France) : Défis et perspectives de la simulation des explosions sous-marines et de leurs effets
Predicting the effects of an underwater explosion on a structure remains a major challenge in numerical simulation, particularly due to the high computational costs involved and the difficulties associated with experimental validation of models. Current approaches will be reviewed in order to identify their main strengths, limitations, and fields of application. Recent developments and future perspectives will also be discussed, with a particular focus on approaches aimed at reducing computational costs, facilitating parametric studies, and expanding the exploration of complex scenarios involving hydrodynamic phenomena and structural response.