Projekt

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A multibeam-bathymetric device to acquire high-resolution lake floor morphologic data

Titel Englisch A multibeam-bathymetric device to acquire high-resolution lake floor morphologic data
Gesuchsteller/in Anselmetti Flavio S.
Nummer 133790
Förderungsinstrument R'EQUIP
Forschungseinrichtung
Eawag
Institut für Geologie Universität Bern
Hochschule Universität Bern - BE
Hauptdisziplin Geologie
Beginn/Ende 01.08.2011 - 31.12.2012
Bewilligter Betrag 230'000.00
Alle Daten anzeigen

Alle Disziplinen (2)

Disziplin
Geologie
Geomorphologie

Keywords (6)

bathymetry; lakes; delta; natural hazards; sediment processes; mass movements

Lay Summary (Deutsch)

Lead
Lay summary

Die verborgene Topographie auf dem Grund von Seen und Meeren (Bathymetrie) ist für viele Gebiete nicht im Detail bekannt. Da sie nicht direkt beobachtet werden kann, wird sie üblicherweise mittels Geländemodellen dokumentiert, die auf einer grossen Anzahl von Tiefenmessungen beruhen. Früher wurden für diese Messungen Einzellotungen oder Echolotprofile verwendet, welche sich allerdings nur für eine vergleichsweise grobe Aufnahme der Bathymetrie eignen. In den letzten Jahren hat sich für diese Aufgabe eine neue Klasse von akustischen Geräten durchgesetzt: So genannte Fächerlotsysteme erfassen Tausende von Tiefenpunkten pro Sekunde und ermöglichen eine effiziente Vermessung von grossen Gebieten mit einer bisher unerreichten räumlichen Auflösung in der Grössenordnung von 1 m.

Dieses Projekt beabsichtigt die Beschaffung eines modernen Fächerlotsystems für Forschungszwecke. Dieses Gerät wird es verschiedenen Forschungsgruppen ermöglichen, Geländemodelle zu erfassen, welche sich für detaillierte geomorphologische Studien unter Wasser eignen. Einsatzgebiete sind unter anderem die grossen Seen der Schweiz mit ihren Flussdeltas, wo Sedimentationsprozesse, zeitliche Veränderungen der Seebodenmorphologie oder auch Spuren grosser Massenbewegungen untersucht werden können. Daraus gewonnene Erkenntnisse ermöglichen es, Risiken abzuschätzen, welche solche Prozesse für Seeanrainer darstellen.

Viele weitere Forschungsbereiche profitieren von genauen bathymetrischen Daten. Die hohe räumliche Auflösung erlaubt beispielsweise die Kartierung von Wasser- und Gasaustritten an der Sedimentoberfläche, so dass Beprobungen gezielt erfolgen können. Zudem können Gasblasen in der Wassersäule detektiert und daraus Stoffflüsse abgeschätzt werden. Neotektonische Verschiebungen an aktiven Bruchzonen in der Erdkruste können Verschiebungen an der Sedimentoberfläche verursachen, welche mit Hilfe von präzisen Geländemodellen erfasst werden können. Da einige dieser Anwendungen eine sehr hohe Genauigkeit erfordern, ist zusätzlich geplant, methodische Verbesserungen für hydrographische Vermessungen zu entwickeln, insbesondere im Bereich der Qualitätskontrolle und der Integration von modernen Satellitennavigationssystemen.


Direktlink auf Lay Summary Letzte Aktualisierung: 21.02.2013

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Publikationen

Publikation
Sediment mobilization deposits from episodic subsurface fluid flow—A new tool to reveal long-term earthquake records?
Reusch A., Moernaut J., Anselmetti F.S., Strasser M. (2016), Sediment mobilization deposits from episodic subsurface fluid flow—A new tool to reveal long-term earthquake records?, in Geology, 44(4), 243-246.
Giant lacustrine pockmarks with subaqueous groundwater discharge and subsurface sediment mobilizationGIANT LACUSTRINE POCKMARKS
Reusch Anna, Loher Markus, Bouffard Damien, Moernaut Jasper, Hellmich Franziska, Anselmetti Flavio S., Bernasconi Stefano M., Hilbe Michael, Kopf Achim, Lilley Marvin D., Meinecke Gerrit, Strasser Michael (2015), Giant lacustrine pockmarks with subaqueous groundwater discharge and subsurface sediment mobilizationGIANT LACUSTRINE POCKMARKS, in Geophysical Research Letters, 42(9), 3465-3473.
Mass Movement-Induced Tsunami Hazard on Perialpine Lake Lucerne (Switzerland): Scenarios and Numerical Experiments
Hilbe Michael, Anselmetti Flavio S. (2015), Mass Movement-Induced Tsunami Hazard on Perialpine Lake Lucerne (Switzerland): Scenarios and Numerical Experiments, in Pure and Applied Geophysics, 172(2), 545-568.
Into the abyss of Lake Geneva: the elemo interdisciplinary field investigation using the MIR submersibles
Wüest Alfred, Anselmetti Flavio S., Arey J. Samuel, Ibelings Bastiaan W., Loizeau Jean-Luc, Vennemann Torsten, Lemmin Ulrich (2014), Into the abyss of Lake Geneva: the elemo interdisciplinary field investigation using the MIR submersibles, in Aquatic Sciences, 76(S1), 1-6.
Lake dwellers occupation gap in Lake Geneva (France–Switzerland) possibly explained by an earthquake–mass movement–tsunami event during Early Bronze Age
Kremer K., Marillier François, Hilbe Michael, Simpson Guy, Dupuy David, Ble J.F. Yrro, Rachoud-Schneider Anne-Marie, Corboud Pierre, Bellwald Benjamin, Wildi Walter, Girardclos Stéphanie (2014), Lake dwellers occupation gap in Lake Geneva (France–Switzerland) possibly explained by an earthquake–mass movement–tsunami event during Early Bronze Age, in Earth and Planetary Science Letters, 385, 28-39.
Signatures of slope failures and river-delta collapses in a perialpine lake (Lake Lucerne, Switzerland)
Hilbe Michael, Anselmetti Flavio S. (2014), Signatures of slope failures and river-delta collapses in a perialpine lake (Lake Lucerne, Switzerland), in Sedimentology, 61(7), 1883-1907.
Sediment dynamics in the subaquatic channel of the Rhone delta (Lake Geneva, France/Switzerland)
Corella J. P., Arantegui A., Loizeau J. L., DelSontro T., le Dantec N., Stark N., Anselmetti F. S., Girardclos S. (2013), Sediment dynamics in the subaquatic channel of the Rhone delta (Lake Geneva, France/Switzerland), in Aquatic Sciences, 76, 73-87.
Searching the Rhone delta channel in Lake Geneva since François-Alphonse Forel
Girardclos Stephanie et al (2012), Searching the Rhone delta channel in Lake Geneva since François-Alphonse Forel, in Archives des Sciences, 65, 103-118.
Subaqueous morphology of Lake Lucerne (Central Switzerland): implications for mass movements and glacial history
Hilbe Michael, Anselmetti Flavio S., Eilertsen Raymond S., Hansen Louise, Wildi Walter (2011), Subaqueous morphology of Lake Lucerne (Central Switzerland): implications for mass movements and glacial history, in Swiss Journal of Geosciences, 104(3), 425-443.
Reconstructing 4000 years of mass movement and tsunami history in a deep peri-Alpine lake (Lake Geneva, France-Switzerland)
Kremer Katrina, Hilbe Michael, Simpson Guy, Decrouy Laurent, Wildi Walter, Girardclos Stéphanie, Reconstructing 4000 years of mass movement and tsunami history in a deep peri-Alpine lake (Lake Geneva, France-Switzerland), in Sedimentology, in press.

Zusammenarbeit

Gruppe / Person Land
Formen der Zusammenarbeit
Geology, University Berne Schweiz (Europa)
- vertiefter/weiterführender Austausch von Ansätzen, Methoden oder Resultaten
- Publikation

Kommunikation mit der Öffentlichkeit

Kommunikation Titel Medien Ort Jahr
Medienarbeit: Printmedien, Online-Medien Le lac Léman a perdu 86 cm de profondeur Tribune de Genève Westschweiz 2012
Medienarbeit: Radio, Fernsehen Le lac Léman a perdu 86 cm de profondeur en 125 ans Radio Cité, Grand Format Westschweiz 2012
Medienarbeit: Radio, Fernsehen Le Léman sous la loupe RTS la 1ère Westschweiz 2012
Medienarbeit: Printmedien, Online-Medien L'explorateur des lacs Tribune de Genève Westschweiz 2012

Verbundene Projekte

Nummer Titel Start Förderungsinstrument
121666 Quantifying human impact and recent climate change using clastic sediments from lacustrine records in western Switzerland 01.02.2010 Projektförderung (Abt. I-III)
123923 Lake Kivu: Learning from the past for managing its future 01.06.2009 Forschungspartnerschaft Nord/Süd: Joint Research Projects
147689 SEDFATE:Sediment fate in a changing watershed during the Anthropocene 01.02.2014 Sinergia
120988 International Continental Scientific Drilling Program (ICDP) 01.01.2008 Forschungsinfrastrukturen
124981 The Swiss contribution to the Lake Van Drilling Project: 500000 years of environmental and climate change in Eastern Anatolia (Science Part) 01.01.2010 Projektförderung (Abt. I-III)
121909 FloodAlp! Frequency and intensity of extreme floods in the Alps through the Holocene and implications for natural hazards in future climate scenarios 01.12.2008 Projektförderung (Abt. I-III)
133481 DYNAMITE: Dynamic Nankai Trough (Japan) and Swiss Molasse Basin: Investigating NeoTectonics, Paleo-Earthquakes and associated Geohazards 01.10.2011 SNF-Förderungsprofessuren
132155 Noble-gas and fluid transport processes in lake sediments 01.09.2011 Projektförderung (Abt. I-III)
146889 Quantifying human impact and recent climate change using clastic sediments from lacustrine records in Western Switzerland (Phase 2) 01.06.2013 Projektförderung (Abt. I-III)

Abstract

This proposal seeks funds for the purchase of a multibeam sonar bathymetric device that is capable of acquiring high-resolution digital elevation models from lake or river floors with typical grid cells of few dm to 1 meter (similar or better than Lidar data on land). Such a device is currently not available in Switzerland and would provide a quantum leap in quality of subaquatic lake floor maps, as currently available data is usually several decades old and based on single-soundings with grid cells of 10s to 100s of meters.Numerous scientific questions and projects can only be addressed with such high-resolution lake floor data being available. The advantage of the ability to perform repeated measurements ('4D') allows determining time series of lake floor topographies, for instance in delta areas, so that sediment budgets influenced by large flood events can be quantified. Knowledge of erosional and depositional areas is crucial in predicting the future evolution of delta areas and to quantify how human land use in the catchment may affect the sediment budgets and delta morphologies. Furthermore, the device allows to extend the natural hazard maps made onshore to the subaquatic domain. Subaquatic slopes within lakes are frequently affected by mass movements and impacting rockfalls, both of which may be tsunamigenic. Multibeam bathymetric maps allow a basin-wide evaluation of areas prone to such mass movements, which, when combined with subsurface data from seismic surveying and sediment cores, allows to single out potential areas of future events. In addition, surface features of incipient slides, only detectable by high-resolution lake floor imagery, provide further evidence of current sublacustrine hazards. In a similar fashion, and as often shown in the marine environment (but barely in lakes), the device will allow location and investigations of subaquatic fluid seeps, such as mud volcanoes, pockmarks and subaquatic springs, which will allow precise sampling of composition and amounts of these fluids. Methane or CO2 released from such vents are not only crucial for the lake floor biological community but also for slope stability issues and, if the bubbles reach the lake's surface, for contribution of greenhouse gases to the atmosphere. Multibeam bathymetric data will further be a crucial prerequisite to locate neotectonic surface structures in lakes. Several areas will be investigated (e.g. Lake Neuchâtel) that are suspected to host seismically active faults. While it is difficult to locate such structures onshore, the calm lake floor environment offers an ideal area to search for these faults, eventually contributing to the currently heated debate on the neotectonic state of the Swiss perialpine region. Next to addressing these questions in lakes, such high-resolution data can also be acquired in rivers in order to show the temporal evolution of morphologies in river channels, i.e. during major flood event, a process critical in river restoration projects.Next to using the multibeam system in these applied research projects, we intend to push this fairly new technology forward by developing advanced data analysis and error estimation methodologies by a rigorous error modeling and quality assessment of the results. Moreover, establishing an active subaquatic beacon network will further increase the potential of the multibeam system by increasing the accuracy of 4D-surveys that will potentially allow determination of lake- and seafloor deformations as expected for instance in tectonically active areas.We propose SNF to cover 50 % of the acquisition costs for such a system and already have the remaining 50 % allocated from various institutions, i.e. Eawag, University of Geneva, ETHZ-Geodesy and Geodynamics Lab (GGL), and Landesanstalt für Umwelt, Messungen und Naturschutz Baden-Württemberg (representing their lake research institute on Lake Constance). The device will be available within the instrument pool for geophysical lake research equipment for the entire Swiss science community.
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