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High-resolution (HR) 3D seismic acquisition is often not available. This work builds an optimized workflow to convert a dense 2D HR seismic grid into a 3D seismic volume. The task has been developed within a broader project, NUREIEVA, which aims at characterizing a metal-rich onshore and shallow marine mine tailings deposit in Portmán Bay, Murcia, Spain. Hence, in the framework of the NUREIEVA project a very dense set of 2D HR seismic lines was acquired using a hull-mounted Kongsberg TOPAS PS18 single-channel parametric source. The acquired seismic grid consisted of 1309 2D lines, with an approximate distance between lines of 10 m, covering an area of 7.45 km2 and yielding a vertical resolution of 15 cm, very high if compared to conventional seismic reflection data. In order to visualize the internal architecture of the mine tailings deposit in all directions, it is desirable to convert the dense 2D network of lines into a full 3D data volume. For this purpose, a new optimized 2D to 3D conversion processing flow has been designed. Given the specific characteristics of the input data, a number of challenges had to be addressed, namely: (i) a very high vertical resolution that differs by at least two orders of magnitude from the horizontal resolution; (ii) a large data volume (2 TB), which involves extensive computing time; (iii) the heterogeneity in the acquisition parameters. Because of this, the lines had to be processed previously to the 3D interpolation to homogenize the imaging characteristics and signal content. This new methodology can be now applied for obtaining a 3D volume to any case where a single channel dense 2D seismic grid is available. Furthermore, if duly adapted to each particular scenario, it represents a low cost alternative to conventional HR 3D seismic and could prevent further seismic shooting.

EGU General Assembly - Online , 4-8 May 2020, High-resolution (HR) 3D seismic acquisition is expensive and often not available due to a variety of reasons. This work builds an optimized workflow to convert a dense 2D HR seismic grid into a 3D seismic volume. The task has been developed within a broader project, NUREIEVA, which aims at characterizing a metal-rich onshore and shallow marine mine tailings deposit in Portmán Bay, Murcia, Spain, which developed from 1957 to 1990. Hence, in the framework of the NUREIEVA project a very dense set of 2D HR seismic lines was acquired. The geophysical equipment used to capture the submarine extent, thickness and internal structure of the mine tailings deposit was a hull-mounted Kongsberg TOPAS PS18 single-channel parametric source. The seismic grid thus acquired consisted of 1309 2D lines, with an approximate distance between lines of 10 m, covering an area of 7.45 km2. The parametric source yielded a vertical resolution of 15 cm, which is very high if compared with conventional seismic reflection data. In order to visualize the internal architecture of the mine tailings deposit in all directions, it is desirable to convert the dense 2D network of lines into a full 3D data volume. Such a data volume is intended to assist reaching faster deposit delimitation and more accurate volumetric calculations. For this purpose, a new optimized 2D to 3D conversion processing flow including a 3D interpolation scheme has been designed. Given the specific characteristics of the input data, a number of challenges had to be addressed, namely: (i) a very high vertical resolution that differs by at least two orders of magnitude from the horizontal resolution; (ii) a large data volume (2 TB), which involves extensive computing time; (iii) the heterogeneity in the acquisition parameters. Because of this, the lines had to be processed previously to the 3D interpolation to homogenize the imaging characteristics and signal content. This new methodology can be now applied for obtaining a 3D volume to any case where a single channel dense 2D seismic grid is available. Furthermore, the new methodology, duly adapted to each particular scenario, represents a low cost alternative to conventional HR 3D seismic and could prevent further seismic shooting in areas when 2D data is already available.

Multibeam echosounders can generate vast amounts of data when recording the complete water column, which poses logistic, economic and technical challenges. Lossy data compression can reduce data size up to one or two orders of magnitude, but often at the expense of significant image distortion. Lossless compression ratios tend to be modest and at a high computing cost. In this work we test a high-performance data compression algorithm, FAPEC, initially developed for Space data communications with low computing requirements. FAPEC provides good compression ratios and supports tailored pre-processing stages. Here we show its advantages over standard and high-end lossless compression solutions currently available, both in terms of ratios and speed, R+D work on FAPEC is supported by the ESA Business Incubation Programme through Barcelona Activa, by the MINECO (Spanish Ministry of Economy) – FEDER through grants ESP2014-55996-C2-1-R, AYA2014-59084-P and MDM-2014-0369 of ICCUB (Unidad de Excelencia ‘María de Maeztu’), and by the AGAUR. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 658358 (D. Amblas). The authors acknowledge funding received from the Spanish RTD grant NUREIEV (CTM2013-44598-R) and from EC contract MIDAS (GA-603418). GRC Geociencies Marines is recognized by Generalitat de Catalunya as an excellence research group (ref. 2014 SGR 1068).

24e Réunion des Sciences de la Terre (RST Pau 2014), 27 au 31 Octobre 2014, Pau.- 1 page, The Ebro margin, NW Mediterranean, has experienced significant sediment input during the Plio-Quaternary, which translates into extensive progradation. A conspicuous feature of the Ebro margin is a dense network of submarine canyons. These canyons are incised

The Aysén fjord is a 65 km long, east-west oriented fjord in Chilean Patagonia, located approximately at 45.4ºS and 73.2ºW, with a maximum water depth of 345 m. The fjord receives at present the riverine input of Aysén, Pescado, Condor and Cuervo rivers, which drain the surrounding up to 2000 m high Patagonian Andes. The fjord is crossed by a number of faults associated to the seismically active Liquiñe-Ofqui Fault Zone, a major trench parallel intra-arc fault system. After a four-month period of moderate seismicity, an Mw 6.2 earthquake on 21 April 2007 triggered dozens of subaerial landslides along the fjord flanks. Some of the landslides reached the fjord water mass, generating a series of tsunami-like displacement waves that impacted the adjacent coastlines with 3-12 m, locally over 50 m high run-ups, causing ten fatalities and severe damage to salmon farms. The research cruise DETSUFA on board BIO Hespérides in March 2013 mapped the submerged morphology of the fjord and gathered air-gun seismic profiles and sediment gravity cores in order to characterise the footprint of the landslides in the fjord floor. Very-high resolution multibeam bathymetry (4 m cell size) clearly shows the deformation structures created by the landslides in the inner fjord. The landslides descended and accelerated down the submerged fjord flanks, and reached the fjord floor at approx. 200 m water depth generating large, 1 to 10 m deep impact depressions. Sediment removed from these depressions moved radially and piled up in deformation rings formed by compressional ridges 10-15 m in height, block fields and a narrow frontal depression. Up to six >1.5 square km of these structures can be identified in the fjord. In addition, the DETSUFA survey extended beyond the SE-NW-oriented inner fjord past the Cuervo Ridge, located in front of the Cuervo river delta. The ridge, previously interpreted as a volcanic transverse structure, has most probably acted as a limit for grounding ice in the past, as suggested by the presence of melt-water channels lateral to the ridge. Beyond the ridge, the fjord smoothens and deepens to more than 330 m forming an enclosed basin before turning SW. There, it shallows back across a field of streamlined submerged hills of glacial origin. The external Aysén fjord, before joining to Canal Costa and Canal Moraleda, is characterized by three volcanic cones, one of them forming Isla Colorada – which also acted as a glacial limit – and the other two totally submerged and previously unknown. The largest one is 160 m high, 1.3 km in diameter and tops at 67 m water depth. This data set illustrates the complex interaction between fluvial, glacial, tectonic, volcanic and gravity processes and evidences the recent lively geological history of Aysén fjord., N/A

EGU General Assembly 2013, 7-12 April, 2013, Vienna, Austria, The offshore displacement of bottom trawling fleets has raised concerns over the impact of this human activity on deep-sea ecosystems and associated living resources, which are characterized by a lower resilience than shallow water correlatives. However, the effects of bottom trawling on sediment remobilization across continental margins and on the alteration of seafloor morphology still remain largely unaddressed. We present a compilation of results from studies conducted during the last decade in the La Fonera (Palamós) submarine canyon (NW Mediterranean Sea), where a bottom trawling fishing fleet is active on a daily basis at depths from 400 to 800 m. Deployments of mooring lines equipped with punctual and profiling current-meters, turbidimeters and sediment traps have documented that trawling gears passing along the canyon flanks generate daily sediment gravity flows, implying a periodic sediment removal from fishing grounds. These sediment-laden flows are able to reach the main canyon axis and progress to a minimum depth of 1200 m. Also, sediment accumulation rates in the lower canyon have increased since the industrialization of the local trawling fleet (1970s), suggesting a human-induced enhancement of along-canyon transfer of sediments from the fishing grounds to greater depths. Sedimentological and 210Pb analysis of interface sediment cores collected from the canyon flanks confirm that widespread erosion and stirring of surface sediments is notable on trawled areas when compared to control (untrawled) sites at similar depths. This chronic reworking and removal of surface sediments from trawling grounds has ultimately led to modifications of the seafloor morphology over large spatial scales, as revealed by high-resolution multibeam bathymetry and Vessel Monitoring Systems (VMS) data sets. Untrawled canyon flank segments are dominated by a dense network of tributary valleys that progress upslope from the main canyon axis, reaching up to five orders of bifurcation. Such complex morphology is missing in the trawled depth range and slightly below, where the sea floor becomes smoother and only the main branches of the tributary valley networks are preserved. Given the global dimension of commercial bottom trawling, our findings suggest that this human activity may have become a significant driver of sediment dynamics and seascape evolution over substantial parts of the world's upper continental slopes