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Discussing submarine canyons dynamics through a multidisciplinary approach allowed to identify both advances in knowledge and remaining gaps concerning the controlling factors underlying the formation, development, ecological functioning and vulnerability of canyons at various time scales. As a result, we identified a number of recommendations for future research and actions that the interested reader will discover in this synthetic chapter, drafted as a collective effort in the months following our meeting. The subsequent chapters, each written by a workshop participant, detail the specificities and dynamics of of submarine canyons within and beyond the Mediterranean domain. Versión del editor

In order to define seismic hazard with sufficient accuracy required for engineering applications, we initiated a multidisciplinary geoscientific study offshore western Peloponnese, focusing on the Kyparissiakos Gulf. Multibeam swath bathymetry localised unstable coastal slopes, which were later investigated by high resolution seismic profiles. Sediments and crustal structures were studied by multi-channel seismic recordings and active large-offsets seismic profiling. We established an onshore/offshore local seismic array that recorded 3500 micro-earthquakes in two months, and combined the results with historical and digital seismicity data in order to understand the active crustal deformation. These findings were further combined with geological mapping and tectonic observations from onshore Peloponnese and available offshore data. All this geologic and tectonic information was coupled with evidence from the analysis of historical and recent seismicity with the aim of identifying the seismogenic sources. We have defined nine seismogenic zones in western Peloponnese that are significantly different from those published in the literature. The new zonation addresses more accurately the deformation of the crust and sediments, and is the basis for a reliable seismic hazard analysis and seismic risk assessment. We identified a large area of the northern Peloponnese and the lonian islands of Lefkas, Cephalonia, Zakynthos and Strophades, to be involved in a SW-ward oriented crustal extrusion, dominated by two major dextral deforming strike slip faults: Cephalonia and Andravida with their offshore prolongation. Some changes with respect to the Greek zonation in the literature have been introduced in the region surrounding the new nine seismogenic zones to reach a homogeneous cover of the whole Peloponnese. © 2014 - OGS.

International audience; Off northwest Libya the Cyrenaica foreland basin domain and its Pan-African continental crust, which constitute the African promontory, are overthrusted by the Mediterranean Ridge Complex. The thrust belt contact and its seismic stratigraphy have been analysed using pre-stack depth-migrated multichannel seismic (MCS) lines recorded during the MEDISIS survey (2002). The geometry and sedimentary distribution analysis through the wedge-top depocentres allow reconstruction of schematic cross-sections of the tectono-sedimentary wedge that includes two major thrust sequences separated by an apparently poorly deformed transition zone. Based on time-space variation of several piggyback basins, we propose that these thrust sequences relate to distinct phases of shortening. (1) A first event, which probably occurred just prior to the Messinian crisis in latest Miocene (Tortonian times?) and (2) A second event, that has finally led to the present-day overthrusting of the Mediterranean Ridge over the Libyan continental slope.

Two highly active mud volcanoes located in 990-1,265 m water depths were mapped on the northern Egyptian continental slope during the BIONIL expedition of R/V Meteor in October 2006. High-resolution swath bathymetry and backscatter imagery were acquired with an autonomous underwater vehicle (AUV)-mounted multibeam echosounder, operating at a frequency of 200 kHz. Data allowed for the construction of similar to 1 m pixel bathymetry and backscatter maps. The newly produced maps provide details of the seabed morphology and texture, and insights into the formation of the two mud volcanoes. They also contain key indicators on the distribution of seepage and its tectonic control. The acquisition of high-resolution seafloor bathymetry and acoustic imagery maps with an AUV-mounted multibeam echosounder fills the gap in spatial scale between conventional multibeam data collected from a surface vessel and in situ video observations made from a manned submersible or a remotely operating vehicle.

Depth migration of seismic reflection profiles across the Mediterranean Ridge accretionary complex between the African and Eurasian blocks illustrates profound variations in the geometry and internal structure along strike. Structural interpretations of four cross sections, together with bathymetric and acoustic surface information and drilling data, are used to volumetrically balance the amount of subduction versus accretion with time. Results suggest the existence of three distinct scenarios, with a jump in décollement in the west, intense backthrusting in the central part between Libya and Crete, and transcurrent tectonism in the east. The onset of accretion coincides with exhumation of thrust sheets (∼19 Ma), followed by rapid sediment accretion with thick, evaporite-bearing incoming successions facilitating outward growth of the wedge. The minimum rate of accretion (20–25% of the total sediment supply) is observed in the central portion where the ridge suffers maximum deformation. Here the indenting leading edge of the African Plate apparently forces the sediment into subduction, or local underplating. In contrast, an estimated 40–60% of the available sedimentary input was accreted in the western domain where collision is less accentuated. The results support the hypothesis that highly destructive forearc collisional events, like slab break off and exhumation of thrust sheets, can be followed by periods of accretion and continuous growth of accretionary wedges.

Methane seepage at mud volcanoes around the world continues to be of broad international interest for a number of reasons. Among these, seafloor methane is a potentially important contributor to global warming. In addition, dewatering and degassing of sediments and the formation of fluid migration pathways is important not only to sedimentologists, but also to hydrocarbon reservoir engineers and hydrologists.

During May 1990 and January-February 1991, an extensive geophysical data set was collected over the Côte d'Ivoire-Ghana continental margin, located along the equatorial coast of West Africa. The Ghana margin is a transform continental margin running subparallel to the Romanche Fracture Zone and its associated marginal ridge - the Côte d'Ivoire-Ghana Ridge. From this data set, an explosive refraction line running approximately 150 km, ENE-WSW between 3°55'N, 3°21'W and 4°23'N, 2°4'W, has been modelled together with wide-angle airgun profiles, and seismic reflection and gravity data. This study is centred on the Côte d'Ioivre Basin located just to the north of the Côte d'Ivoire-Ghana Ridge, where bathymetric data suggest that a component of normal rifting occurred, rather than the transform motion observed along the majority of the equatorial West African margin. Traveltime and amplitude modelling of the ocean-bottom seismometer data shows that the continental Moho beneath the margin rises in an oceanward direction, from approximately 24 km below sea level to approximately 17 km. In the centre of the line where the crust thins most rapidly, there exists a region of anomalously high velocity at the base of the crust, reaching some 8 km in thickness. This higher-velocity region is thought to represent an area of localized underplating related to rifting. Modelling of marine gravity data, collected coincident with the seismic line, has been used to test the best-fitting seismic model. This modelling has shown that the observed free-air anomaly is dominated by the effects of crustal thickness, and that a region of higher density is required at the base of the crust to fit the observed data. This higher-density region is consistent in size and location with the high velocities required to fit the seismic data. (Résumé d'auteur)

Active deformation of the sea-floor of the Hellenic trench has been observed using the Cyana SP-3000 submersible. The strain pattern observed on a scale of a few kilometers is similar to the one deduced from an analysis of Seabeam morphological maps on a scale of tens of kilometers. The overall strain pattern is compatible with subduction of the Mediterranean sea-floor toward the northeast. It is characterized by underthrusting in the Western Ionian branch and left-lateral strike-slip faulting in the Eastern Strabo branch.

Papadopoulos, Gerassimos ... et. al.-- 29 pages, 14 figures, 2 tables, The origin of tsunamis in the Mediterranean region and its connected seas, including the Marmara Sea, the Black Sea and the SW Iberian Margin in the NE Atlantic Ocean, is reviewed within the geological and seismotectonic settings of the region. A variety of historical documentary sources combined with evidence from onshore and offshore geological signatures, geomorphological imprints, observations from selected coastal archeological sites, as well as instrumental records, eyewitnesses accounts and pictorial material, clearly indicate that tsunami sources both seismic and non-seismic (e.g. volcanism, landslides) can be found in all the seas of the region with a variable tsunamigenic potential. Local, regional and basin-wide tsunamis have been documented. An improved map of 22 main tsunamigenic zones and their relative potential for tsunami generation is presented. From west to east, the most important tsunamigenic zones are situated offshore SW Iberia, in the North Algerian margin, in the Tyrrhenian Calabria and Messina Straits, in the western and eastern segments of the Hellenic Arc, in the Corinth Gulf of Central Greece, in the Levantine Sea offshore the Dead Sea Transform Fault and in the eastern side of the Marmara Sea. Important historical examples, including destructive tsunamis associated with large earthquakes, are presented. The mean recurrence of strong tsunamis in the several basins varies greatly but the highest event frequency (1/96. years) is observed in the east Mediterranean basin. For most of the historical events it is still unclear which was the causative seismic source and if the tsunami was caused by co-seismic slip, by earthquake-triggered submarine landslides or by a combination of both mechanisms. In pre-historical times, submarine volcanic eruptions (i.e. caldera collapse, massive pyroclastic flows, volcanogenic landslides) and large submarine landslides caused important tsunamis although little is known about their source mechanisms. We conclude that further investigation of the tsunami generation mechanisms is of primary importance in the Mediterranean region. Inputs from tsunami numerical modeling as well as from empirical discrimination criteria for characterizing tsunami sources have been proved particularly effective for recent, well-documented, aseismic landslide tsunamis (e.g., 1963 Corinth Gulf, 1979 CÔte d'Azur, 1999 Izmit Bay, 2002 Stromboli volcano). Since the tsunami generation mechanisms are controlled by a variety of factors, and given that the knowledge of past tsunami activity is the cornerstone for undertaking tsunami risk mitigation action, future interdisciplinary research efforts on past tsunamis are needed. © 2014 Elsevier B.V., The National Observatory of Athens, the University of Bologna, the Istituto Nazionale di Geofisica e Vulcanologia (INGV), the Hellenic Center for Marine Research, the Middle East Technical University as well as the Universidad de Cantabria acknowledge co-funding from the EU-FP6 TRANSFER research project, 2006–2009, contract n. 037058. The National Observatory of Athens, the University of Bologna and the Universidad de Cantabria are co-funded by the DG ECHO of EU, project NEARTOWARN, 2012–2013, contract n. 230301/2011/614039/SUB/A5. Barcelona-CSI acknowledges that this work has been carried out within Grups de Recerca de la Generalitat de Catalunya B-CSI (2009 SGR 146) and the support of the Spanish Ministry of Science and Innovation (MICINN) through National Projects EVENT (CGL2006-12861-C02-02), MEDOC (CTM2007-66179-C02-02/MAR), POSEIDON (CTM2010-21569), SHAKE (CGL2011-30005-C02-02), and HADES (CTM2011-30400-C02-01 and CTM2011-30400-C02-02), Complementary Action NEAREST-SEIS (CGL2006-27098-E/BTE), the EU Programme “Global Change and Ecosystems” contract n. 037110 (NEAREST), ESF TopoEurope TOPOMED project (CGL2008-03474-E/BTE) and the IGCP-585. Τhe Istituto Nazionale di Geofisica e Vulcanologia (INGV) acknowledges the Italian Department of Civil Protection for funding a project in the frame of the 2007–2009 agreement

The potentialities of pseudopolarographic approach regarding trace metal speciation were explored. Recorded pseudopolarogram of a particular metal serves as a fingerprint of the analyzed sample. It gives initial information related to qualitative and quantitative purpose: a first approximation of trace metal distribution with respect to labile and inert metal complexes and the strength of inert metal complexes present in natural sample. Several model electrolyte solutions and natural estuary/seawater samples containing different quantity of Dissolved Natural Organic Matter (DNOM) were used in this study. In addition, Differential Pulse Anodic Stripping Voltammetry (DPASV) measurements were carried out with logarithmic additions to reach information about DNOM complexing capacities and stability constants.

Solubility of iron(III)-glycine-NTA mixed complex in aquatic solution was measured by cathodic voltammetry with static mercury drop electrode. Experimental determined Fe(III) retention time in soluble phase at pH = 8.1 in 0.1 mol L-1 NaClO4 was found to be more than 18 hours. It was achieved by addition of NTA to the iron(III)-glycine water solution. Under these conditions, iron(III) hydrolysis was sufficiently suppressed.

Several electrochemical techniques and methods were used to explore electrochemical behavior of copper in determination of its complexation parameters in model electrolyte solutions, as well as in fresh, brackish and sea water. I was shown that adsorption of natural organic matter (NOM) strongly influences electrochemical reaction of copper during anodic stripping step having consequences in obtaining proper copper complexing parameters. Experimental procedure setup is proposed to overcome these difficulties.