Cord Papenberg

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Nima Nezafati

Deutsches Bergbau-Museum, Bochum

Ernst Pernicka

Universität Heidelberg

Nicolas Flament

University of Wollongong

Nick Roberts

British Geological Survey

David Seamon

Kansas State University

Karen Ruebens

University of Reading

Peter D Clift

University College London

Giampaolo Salice

Università degli Studi di Cagliari

Manuel Will

Eberhard Karls Universität Tübingen

Anil M Pophare

RTM Nagpur University

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Papers by Cord Papenberg

Schall und Schwingungen Wellen und Turbulenz in sensibler Umgebung

by Ivor Nissen, Cord Papenberg, Jens Schneider von Deimling, Dirk Klaeschen, Dietrich Wittekind, Hans-elias Bree, Moustafa Abdel-maksoud, Andreas Galka, Nikolai Kornev, and Susanne Lehner

Der Fachausschuss (FA) Akustik der Deutschen Gesellschaft für Wehrtechnik e. V. (DWT) hat vom 17.... more Der Fachausschuss (FA) Akustik der Deutschen Gesellschaft für Wehrtechnik e. V. (DWT) hat vom 17. bis 20. September 2012 am GEOMAR – Helmholtz-Zentrum für Ozeanforschung, Kiel eine wissenschaftliche Tagung mit dem Thema Schall und Schwingungen, Wellen und Turbulenz in sensibler Umgebung mit maritimem Schwerpunkt durchgeführt. Traditionell tagte der FA im Emsland an der Wehrtechnischen Dienststelle für Waffen und Munition (WTD 91) im jährlichen Wechsel mit dem FA Optik und Optronik von Prof. Rothe, Helmut-Schmidt-Universität (HSU). Diese zwei FA sind die zwei wissenschaftlichen Gremien der DWT. Vier Tage lang beschäftigten sich 160 Wissenschaftler aus Industrie, Universitäten, Forschungseinrichtungen und Amtsbereich mit einem breiten Themenspektrum in Form eines offenen zivil–militärischen Gedankenaustausches mittels wissenschaftlicher Fachvorträge, Postersession sowie Firmenausstellungen am GEOMAR. Damit stellte dies die bisher größte Veranstaltung dieser Tagungsreihe dar. Nach der Begrüßung der Tagungsteilnehmer durch den Leiter des FA begrüßte Herr Prof. Dr. Peter Herzig, Direktor des GEOMAR, als Gastgeber im Rahmen der Eröffnungsveranstaltung die Gäste. Für die Wehrtechnische Dienststelle für Schiffe und Marinewaffen, Maritime Technologie und Forschung (WTD 71) sprach Herr Dr. Kretschmer in Vertretung des Direktors Herrn Schlichting. Beide Institutionen, GEOMAR und WTD 71 mit ihrem Forschungsbereich, als auch die HSU waren Kooperationspartner der DWT und gestalteten die Tagung mit. Die zur klärende Frage des Tagungskonzeptes lautete: Welches sind im Über- aber insbesondere Unterwasserbereich vertretende Kernthemen auch benachbarter Institutionen, mit denen sich eine maritime Tagung mit zivilen und militärischen Nutzen gestalten lässt? Als Resultat kristallisierten sich sieben Themenbereiche mit insgesamt 44 Vorträgen heraus:
- Geophysik/Turbulenz (Prof. Berndt/Dr. Fiekas)
- Maritime Messtechnik (Dr. Schmidtke)
- Unterwasserkommunikation (Dr. Nissen)
- Akustische Überwachung mit Sensornetzwerken (Dr. Ehlers, Dr. Schulz)
- Schiffbau (Dr. Stuntz)
- Hydroakustik/Grenzschichtturbulenz (Dr. Abshagen)
- Numerische Methoden (Dr. Schäfer, Ehrlich)
Am ersten Tag lag der Schwerpunkt der Veranstaltung auf Geophysik/Turbulenz. Dieses
Fachgebiet wird im benachbarten Forschungsbereich für Wasserschall und Geophysik (FWG) der WTD 71 von Dr. Heinz-Volker Fiekas geleitet, der zusammen mit Prof. Dr. Christian Berndt des GEOMAR den ersten Tag gestaltete. Hier zeigt sich die Verbundenheit beider Institute bezüglich dieses Themas. Im weiteren Verlauf der Tagung spielten neben Fragen der Ortung und Vermessung von Objekten am Meeresboden und in der Wassersäule mittels moderner Satellitentechnik auch die Beobachtung der Meeresoberfläche durch Synthetisches-Apertur-Radar (SAR) für Aufklärungszwecke eine bedeutende Rolle. Identifizierte, durch ein Schiff generierte Oberflächenwellen können die Position des Schiffes verraten. Dr. Susanne Lehner vom Deutschen Zentrum für Luft- und Raumfahrttechnik stellte modernste Möglichkeiten vor. Prof. Tuncay Akal aus der Türkei von SUASIS UNDERWATER SYSTEMS berichtete nicht nur von seiner langjährigen internationalen Erfahrung, sondern stellte ein gemeinsames Forschungsprojekt mit der Firma MICROFLOWN Avisa aus den Niederlanden zur experimentellen Bestimmung der akustischen Schnelle im Wasser vor. Ziel ist es, in die Lage versetzt zu werden, auch unter Wasser dominierende Schallquellen, sogenannte akustische „Hot Spots“, schnell und mobil zu identifizieren. Zivile und militärische Anwendungen haben bekanntlich oftmals dieselben Herausforderungen. Ob man sich zur Aufgabe gemacht hat ein Feldlager im Einsatzgebiet, eine Hafenanlage, ein Schiff auf Reede oder ein ozeanographisches Observatorium zur Erdsystembeobachtung zu schützen, zu sichern, zu überwachen oder zu betreiben, in jedem Fall ist hierzu die Beobachtung von systemrelevanten Daten notwendig. Die technischen oder wissenschaftlichen Herausforderungen sind hierbei in vielen Fällen ähnlich und koinzidieren auch. Es geht um kontinuierliche Datenerfassung und -fusion, moderne Sensornetzwerke, Zeit- und Kosteneffizienz, Satellitenverbindungen, Datenboten und -sammlern wie AUVs und Glider, hydrographische, akustische sowie seismische Messstationen und -verfahren. Bei all dem ist die Akustik gerade im Unterwasserbereich eine dominierende Technologieeinflußgröße. Zur Halbzeit der Tagung ging es nach Laboe, am Ehrenmal vorbei ins Restaurant Baltic Bay
zum Konferenzdinner. In angenehmer, maritimer und stilvoller Atmosphäre direkt am Segelhafen wurden die fachlichen Gespräche fortgesetzt und persönliche Kontakte aufgenommen respektive intensiviert. Dr. Lüder Hogrefe, Geschäftsführer von Raytheon Anschütz GmbH, begrüßte vor Ort die Wissenschaftler und hielt die Dinner Speech. Dr. Hogrefe betonte den zivil-militärischen Ansatz der Tagung, welcher „noch vor 15 Jahren nicht möglich erschien“. Die Veranstaltung hat bewiesen, dass der eingeschlagene Weg diese duale Betrachtung zulässt. Der vorliegende Tagungsband möge dieses bestätigen. Er spiegelt den aktuellen maritimen Forschungsstand bezüglich der oben angegebenen Themenschwerpunkte wieder. Wir bedanken uns bei allen Autoren und Vortragenden für ihre eingestellten Beiträge. Besonderer Dank geht an Frau Angela Günther für die Leitung des Tagungsbüros sowie für die lange Zeit der intensiven Vor- und Nachbereitung. Dank geht ebenfalls an Herrn Michael Krüger für die großartige technische Unterstützung. Es kann nicht unerwähnt bleiben, dass so manche weitere Hilfe im Hintergrund durchaus wahrgenommen wurde, doch sei aus Platzgründen hierfür nur insgesamt, doch keineswegs weniger nachdrücklich, gedankt.

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Zonation of North Alex Mud Volcano highlighted by 3-D active and passive seismic data

ABSTRACT The West Nile Delta forms part of the source of the large turbiditic Nile Deep Sea Fan. ... more ABSTRACT The West Nile Delta forms part of the source of the large turbiditic Nile Deep Sea Fan. Since the late Miocene sediments have formed an up to 10 km thick pile, which includes about 1 - 3 km of Messinian evaporates. The sediment load of the overburden implies strong overpressures and salt-related tectonic deformation. Both are favourable for fluid migration towards the seafloor guided by the fractured margin. The western deltaic system, Rosetta branch, has formed an 80 km wide continental shelf. Here at 700 m water depth the mud volcano North Alex (NA) developed his circular bathymetric feature, which proved to be an active gas and mud-expelling structure. A 3-D high-resolution multichannel seismic survey (IFM-GEOMAR P-Cable system) was completed across the mud volcano. 3-D time migration provided a 3-D data cube with a 6.25 m grid. Vertical seismic sections did reveal a large set of faults located within the main mud volcano as well as surrounding the structure. Internal faults are mainly related to episodic mud expulsion processes and continuous gas and fluid production. Deep cutting external faults surround the structure in a half circle shape. Horizontal amplitude maps (time slices) of indicate recent activity of these faults even up to the seafloor. High gas saturation of the sediments is indicated by inverted reflection events. In the centre the gas front cuts into the seafloor reflection while it dips down with increasing radius. Only with the small grid resolution inward dipping reflections become visible, which form an upward opened concave reflector plane underlying the top gas front. The interpretation assumes an oval lens shaped body (conduit) saturated with gas at the top of the mud volcano. It provides the upper termination of the mud chimney. This separation is further supported by passive seismic observations. Distant earthquakes can stimulate long-period harmonic oscillations in mud volcanoes. Such oscillations are detectable with three-component ocean bottom seismometers (OBS) and are best explained by a gas-saturated volume at - or in close proximity to - the surface. The period of these oscillations is directly linked to the composition and dimension of this volume. Further, these oscillations are associated with pressure changes in the gas volume, which are thought to disturb the balance between gas pressure and water pressure strongly enough to cause degassing in the upper sediment layers of the mud volcano. This way, gas transport and release in mud volcanoes might be triggered by external seismic sources. Additionally, tremors of higher frequencies can be observed at NA Mud Volcano, and are most likely generated in the mud chimney beneath the top gas volume. Further evidence for the existence of a rather deep chimney (&gt;750m) comes from S-wave observations of regional earthquakes. Records from OBS that were placed at the volcano’s centre (1), differ from OBS in greater distance (2). S-wave arrivals suggest the existence of a cylindrical-shaped waveguide beneath OBS of type (1). Such features cannot be seen on OBS of type (2). Thus, S-wave velocities need to be lower in the chimney than in the surrounding, which is a reasonable assumption. Modelling of these waveguides can give the dimension of the chimney (width and depth).

Modeling Submarine Landslide-Generated Waves in Lake Ohrid, Macedonia/Albania

Advances in Natural and Technological Hazards Research, 2013

We study potential tsunami hazards associated with submarine landslides in Lake Ohrid, Macedonia/... more We study potential tsunami hazards associated with submarine landslides in Lake Ohrid, Macedonia/Albania. The transboundary Lake Ohrid located on the Balkan Peninsula shared by Macedonia and Albania is considered to be the oldestcontinuously existing lake in Europe (2-5 Ma), though the age and the origin are not completely unraveled to date. Previous studies by means of hydroacoustic methods have shown that the western margin of Lake Ohrid has a long history of mass wasting. Based on seismic data, slide deposits are found in different stratigraphic levels as well as on the lake floor where they have affected a large area. This study is focused on the well-studied Udenisht Slide Complex covering an area of 27 km 2 within the southwestern part of Lake Ohrid. The Udenisht slide is by far the largest mass movement with an average thickness of 30-40 m and an estimated volume of about 0.11 km 3 . It is therefore well within the limits of submarine landslides that are known to be capable of triggering tsunamis. Using numerical modeling, the propagation of a landslide-generated tsunami with an initial wave height of more than 5 m has been calculated. Run-up heights estimated for coastal communities around the lake are moderate in the north (2-3 m) can reach up to 10 m directly at the site where the slide initiated. This study is a first generation of landslide tsunami hazard assessment for Lake Ohrid and further detailed modeling is recommended for the region.

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3-D Seismic Images of Mud Volcano North Alex, West-Nile Delta, Egypt

… 2010, held 2-7 May …, 2010

... The West Nile Delta forms part of the source of the large turbiditic Nile Deep Sea Fan. ... B... more

Patterns of subsurface fluid-flow at cold seeps: The Hikurangi Margin, offshore New Zealand

Marine and Petroleum Geology, 2013

ABSTRACT Based on multichannel seismic, geoacoustic, and methane sensor data, four different area... more ABSTRACT Based on multichannel seismic, geoacoustic, and methane sensor data, four different areas along the Hikurangi Margin show multiple indications for seep activity including bright spots, transparent zones, vertical chimneys, and the occurrence and distribution of bottom simulating reflectors. Locations where these features reach the seafloor are characterised by high backscatter intensity on sidescan sonar images and transparent zones in sediment echosounder profiles, while methane sensors show episodic, elevated methane concentrations near the seep sites. Methane discharge is facilitated by reduced hydrostatic pressure during low tides. The greatest number of seeps at Opouawe Bank correlates with the highest methane activity along the Hikurangi Margin. High heat flow values on flanks of ridges and low heat flow values on anticlines reflect a topographic effect on subsurface temperatures. Elevated heat flow occurs in the vicinity of seeps on Opouawe Bank. We propose that there are two drivers behind methane seepage with respect to the migration pathways of methane through the gas hydrate stability zone (GHSZ) to the seafloor: (1) structurally controlled and (2) stratigraphically controlled. In the structural model, vertical chimneys are the major pathways for methane through the GHSZ. Part of the upwardly migrating methane forms gas hydrate within the chimney. In the stratigraphic model, methane migration is stratigraphically controlled beneath seeps that are located on bathymetric highs and/or where subsurface anticlines occur beneath seeps. The structurally controlled seeps produce higher methane escape at the seafloor than those that are stratigraphically controlled. A combination of both driving mechanisms results in the highest methane seepage rates at the Tui Seep on Opouawe Bank.

Deep seismic structure of the Tonga subduction zone: Implications for mantle hydration, tectonic erosion, and arc magmatism

Journal of Geophysical Research, 2011

1] We present the first detailed 2D seismic tomographic image of the trench-outer rise, fore-and ... more 1] We present the first detailed 2D seismic tomographic image of the trench-outer rise, fore-and back-arc of the Tonga subduction zone. The study area is located approximately 100 km north of the collision between the Louisville hot spot track and the overriding Indo-Australian plate where ∼80 Ma old oceanic Pacific plate subducts at the Tonga Trench. In the outer rise region, the upper oceanic plate is pervasively fractured and most likely hydrated as demonstrated by extensional bending-related faults, anomalously large horst and graben structures, and a reduction of both crustal and mantle velocities. The 2D velocity model presented shows uppermost mantle velocities of ∼7.3 km/s, ∼10% lower than typical for mantle peridotite (∼30% mantle serpentinization). In the model, Tonga arc crust ranges between 7 and 20 km in thickness, and velocities are typical of arc-type igneous basement with uppermost and lowermost crustal velocities of ∼3.5 and ∼7.1 km/s, respectively. Beneath the inner trench slope, however, the presence of a low velocity zone (4.0-5.5 km/s) suggests that the outer fore-arc is probably fluid-saturated, metamorphosed and disaggregated by fracturing as a consequence of frontal and basal erosion. Tectonic erosion has, most likely, been accelerated by the subduction of the Louisville Ridge, causing crustal thinning and subsidence of the outer fore-arc. Extension in the outer fore-arc is evidenced by (1) trenchward-dipping normal faults and (2) the presence of a giant scarp (∼2 km offset and several hundred kilometers long) indicating gravitational collapse of the outermost fore-arc block. In addition, the contact between the subducting slab and the overriding arc crust is only 20 km wide, and the mantle wedge is characterized by low velocities of ∼7.5 km/s, suggesting upper mantle serpentinization or the presence of melts frozen in the mantle.

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Subduction system variability across the segment boundary of the 2004/2005 Sumatra megathrust earthquakes

by U. Barckhausen, Cord Papenberg, and Alexey Shulgin

Earth and Planetary Science Letters, 2013

Subduction zone earthquakes are known to create segmented patches of co-seismic rupture alongstri... more Subduction zone earthquakes are known to create segmented patches of co-seismic rupture alongstrike of a margin. Offshore Sumatra, repeated rupture occurred within segments bounded by permanent barriers, whose origin however is still not fully understood. In this study we image the structural variations across the rupture segment boundary between the Mw 9.1 December 26, 2004 and the Mw 8.6 March 28, 2005 Sumatra earthquakes. A set of collocated reflection and wide-angle seismic profiles are available on both sides of the segment boundary, located offshore Simeulue Island. We present the results of the seismic tomography modeling of wide-angle ocean bottom data, enhanced with MCS data and gravity modeling for the southern 2005 segment of the margin and compare it to the published model for the 2004 northern segment. Our study reveals principal differences in the structure of the subduction system north and south of the segment boundary, attributed to the subduction of 961E fracture zone. The key differences include a change in the crustal thickness of the oceanic plate, a decrease in the amount of sediment in the trench as well as variations in the morphology and volume of the accretionary prism. These differences suggest that the 961E fracture zone acts as an efficient barrier in the trench parallel sediment transport, as well as a divider between oceanic crustal blocks of different structure. The variability of seismic behavior is caused by the distinct changes in the morphology of the subduction complex across the boundary related to the difference in the sediment supply.

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Schall und Schwingungen Wellen und Turbulenz in sensibler Umgebung

by Ivor Nissen, Cord Papenberg, Jens Schneider von Deimling, Dirk Klaeschen, Dietrich Wittekind, Hans-elias Bree, Moustafa Abdel-maksoud, Andreas Galka, Nikolai Kornev, and Susanne Lehner