Circular Sedimentary Figures of Anthropic Origin in a Sediment Stability Context
- Others:
- Établissement principal du Service hydrographique et océanographique de la Marine (EPSHOM) ; EPSHOM
- Service Hydrographique et Océanographique de la Marine (SHOM) ; Ministère de la Défense
- Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA ) ; Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)
- Géoazur (GEOAZUR 6526) ; Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS) ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
- Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG) ; Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST) ; Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Description
The French POSA project studies the seismic energy released by bomb and mine blasting. This project is based on seismological and acoustical measurements recording during blasting actions in order to study seismic wave propagation nucleated by controlled sources (location and explosive energy). These measurements are compared to numerical modeling of the acoustic and seismic wave propagation based on the most faithful 3D representation of the seabed sediments and underlying rocks. This project first focused on the 3D environment representation based on specific surveys and on two blasting experiments which consist in exploding bombs of different loads at two distinct environmental places. The in-situ measurements reveal several hundred circular figures with very specific characteristics which clearly differentiate them from other sedimentary, biological and geological figures encountered on the seabed. They are found within the whole studied area and their diameter is from 10 to 130 m. About 30 circles by kilometer square are observed without correlation with the depth which varies from 10 to 150m. These sedimentary structures indicate that they have been generated by the explosion of bombs, but at different periods. The oldest ones most probably result from bombs dropped in 1940 and 1944 during the landing of the Allied forces in the region of Toulon. These original anthropic sedimentary figures and their differences compared with other circular structures observed on the seabed are described.
Abstract
International audience
Additional details
- URL
- https://hal.archives-ouvertes.fr/hal-01983416
- URN
- urn:oai:HAL:hal-01983416v1
- Origin repository
- UNICA