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European Geosciences Union (EGU) General Assembly, 7-12 April 2019, Vienna, Austria.-- 1 page, In 2013, we carried out the Galicia-3D controlled-source reflection-refraction seismic experiment at the Deep Galicia rifted margin in the northeast Atlantic Ocean, west of Spain. We acquired more than 3200 km of seismic profiles within a three-dimensional (3D) box measuring 64 by 20 km (1280 km2). The main features within this box are: the peridotite ridge (PR), composed of serpentinized peridotite; a series of fault bounded, rotated basement blocks; and the S reflector, which has been interpreted across most of the box as a low angle detachment fault forming the crust-mantle boundary. Shots from two 3300 cu.in airgun arrays fired alternately in a flip-flop configuration, with a shot spacing of 37.5 m, were recorded by four six-kilometer streamers of R/V Marcus Langseth, as well as by 72 Ocean Bottom Seismometers (OBS) of the Galicia-3D network. We present tomographic results obtained using three well known controlled-source seismic tomography codes: the three-dimensional (3D) first-arrival time seismic tomography code FAST, and the 3D joint refraction-reflection travel-time tomography codes TOMO3D and JIVE3D. Results obtained with three different codes were compared with the seismic reflection images of the area, and this comparison confirms that the main features of the area are accurately represented in all three results. The 3.5, 5 and 6.5 km/s contours match well the top of the acoustic and crystalline basements and the S-reflector, respectively.Largest differences between results ofdifferent codes occur, as expected, in poorly resolved areas. n addition, due to differences in parameterisations and inversion schemes, the same structure is expressed in three different ways in the results. Below the S-reflector, P-wave velocities indicate a degree of serpentinisation of 45 to 30 %. The distribution of the serpentinisation allows us to estimate the amount of water reaching the mantle, and suggests that the water reaches the mantle when faults are active. Our models allow us to explore the relationship between extension inferred from fault heaves and crustal thickness variations in 3D

Evidence and data are still the basis of many discussions in relation to climate change. One of the areas for exploration is how engagement professionals and science communicators might equip environmental scientists and communities to take a confident role in the climate crisis, informing and shaping stories to avoid distorting or oversimplifying the facts. And, at the same time, recognising the implications of climate change for those communities who will be most affected by it. This session is focussed on combining aspects of storytelling, listening and community organising techniques to connect and share practice to surface the tensions around bridging the gap between evidence and equity in achieving net zero in practice. The session draws on work from a new National initiative, led by Professor Hilary Geoghegan, supported by the Natural Environment Research Council.

American Geophysical Union Fall Meeting, 12-16 December 2016, San Francisco, The west Galicia margin (NW Spain) is a magma-poor margin with limited sedimentary cover, providing ideal conditions to study the processes of continental extension and break-up through seismic imaging. In 2013, we collected a 65km x 20km 3D multi-channel seismic dataset extending from the edge of the Galicia Bank over the feather edge of the continental crust to beyond the Peridotite Ridge to the west. The volume has been processed through to 3D prestack time migration and 3D depth conversion and provides 3D images of the hyper-extended continental crust, consisting of well-defined but internally intensely deformed rotated faults blocks with associated syn-kinematic sedimentary wedges. The rotated fault blocks contain possible low-angle normal faults that in places appear to define and elsewhere to offset top basement; we interpret them as early faults that predate the formation of the fault blocks. The early faults are in places cut and offset by the later block-bounding faults that appear to detach downwards onto a bright reflection, the S reflector, a detachment fault and locally the crust-mantle boundary. S is corrugated on both depth and time structure maps, with the corrugations sweeping in an arc from E-W proximally to ESE-WNW towards the ocean. We interpret the corrugations as forming during slip on S and representing the displacement (and hence extension) direction on the detachment leading to breakup. Early synrift sediment within the most recent faults blocks are intensely deformed, representing the internal deformation of the fault blocks. However, in places simple synrift wedges can be seen to thicken towards the block-bounding faults. The angular relationship of the top of these wedges to the block-bounding faults demonstrates that they were deposited during slip on the faults and low-angle slip on the underlying S detachment. Although beneath the continental crust S appears continuous and shows only minor distortion in the vicinity of the block-bounding faults, just east of the Peridotite Ridge, S appears to have been offset by landward-dipping faults associated with the development of the Ridge. We conclude that rifting to breakup was a complex, time variant, 3D process involving slip at low-angles, multiple generations of faults and the unroofing of mantle along later landward-dipping structures