14 pages, 13 figures, 1 table.-- This is a contribution of the Barcelona Center for Subsurface Imaging that is a Grup de Recerca 2017 SGR 1662 de la Generalitat de Catalunya, We present a generalized workflow to retrieve high-resolution P-wave velocity ( VP ) models of complex Earth’s subsurface structures from traditional marine near-vertical seismic reflection experiments. These records have typically offsets too short to map refraction phases and lack low-frequency information. The workflow is composed of three steps: 1) downward continuation (DC) of seismic records to the seafloor to recover diving wave information; 2) travel-time tomography (TTT) of first arrivals obtained from DC data, to retrieve a kinematically correct model; and 3) full-waveform inversion (FWI) of the original streamer dataset, starting with the model obtained with TTT and sequentially introducing higher wavenumber details into the model. We show that the TTT allows overcoming the issues associated with the nonlinearity intrinsic to FWI. We also disentangle envelope and phase from the waveform to choose the objective function most suitable for FWI. We assess the accuracy of initial models and predict the quality of the FWI results by quantifying the early arrival cycle skipping between original and simulated data. The efficiency of the workflow is tested with a challenging synthetic target model, containing vertical boundaries with strong velocity contrasts and velocity inversions embedded in a checkerboard-like pattern. We show that workflow steps 1) and 2) provide a TTT model that is not cycle skipped at the frequencies available in most marine seismic experiments and thus allow step 3) FWI to obtain high-resolution VP models of the subsurface using band- and offset-limited field datasets, traditionally collected in marine airgun and streamer acquisitions, This work has been done in the framework of project FRAME (Reference CTM2015-71766-R) and project ATLANTIS PID2019-109559RB-I00, funded by the Spanish Ministry of Research and Innovation and has also had the funding support of the Severo Ochoa Centre of Excellence accreditation (CEX2019-000928-S), of the Spanish Research Agency (Agencia Española de Investigación, AEI), Peer reviewed

20 pages, 19 figures, 1 table.-- Data Availability Statement: The original seismic images and maps used for this publication are available online (at https://doi.org/10.5281/zenodo.6350585, A poorly defined boundary between the Nubia and Eurasian plates runs along the Northern Tunisian continental margin. The Tunisia margin is deformed by a slow NW–SE trending convergence resulting in a diffuse deformation zone with scarce and scattered seismicity compared to the seismic activity into the neighboring regions to the east and west along the boundary. The area has been poorly studied and therefore its recent evolution is almost unknown, particularly offshore. Here, we present a structural analysis of the active tectonics in this submarine continental margin. The data used for this analysis are high-resolution bathymetric maps together with parametric echosounder images which have allowed to obtain a map of active faulting with unprecedented detail. The structural analysis supports a dominantly transpressive to compressive component of faulting, resulting from the current regional NW–SE trending compressive regime between plates. The North-eastern Domain of the study region contains the highest number of active faults with numerous pockmarks aligned along them. This study shows that the plate boundary across the North Tunisia margin is incipient and poorly developed, which may be due to the fact that deformation is partitioned over a large number of structures, each accommodating a small percentage of convergence, with the exception of the Hayat fault system. The Hayat reverse fault, striking WSW–ENE, is the largest fault system that comparatively may accommodate a greater amount of displacement, and is probably responsible for the uplift of the North-eastern Domain of the continental margin, Data collection and MC were supported by the project Geomargen-2 funded by REPSOL. The work was also supported by the EU project EMODnet-HRSM-2. Additional funding came from the Spanish Ministry of Science and Innovation projects: CTM2011-30400-C02-01 “HADES,” CGL2011-30005-C02-02 “SHAKE,” CTM2015-70155-R “INSIGHT,” PID2019-104668RB-I00 “STRENGTH,” CTM2015-71766-R “FRAME,” and PID2019-109559RB-I00 “ATLANTIS.” ICM has also had funding support of the “Severo Ochoa Centre of Excellence” accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI), Peer reviewed

12 pages, 9 figures, supplementary information https://doi.org/10.1038/s41467-022-31895-z.-- Data availability: Bathymetric and topographic data used in Figs. 1, 2 and 4 are our compilation of the publicly available (EMODnet Bathymetry66 and NASA SRTM topography67) and bathymetry collected in SARAS cruise68. Seismic data plotted in Fig. 1 are from the Instituto Geográfico Nacional (IGN, http://www.ign.es/web/en/ign/portal/sis-catalogo-terremotos) and GNNS velocity vectors and associate errors are from ref. 11 Seismic data were acquired during the Barcelona-CSI marine cruises TOPOMED-GASSIS and EVENT-DEEP Leg 1 (http://gma.icm.csic.es/sites/default/files/geowebs/OLsurveys/index.htm). The seismic images generated for this study have been deposited in the figshare database under accession code 10.6084/m9.figshare.19919140, The current diffuse-strain model of the collision between Africa and Eurasia in the western Mediterranean predicts a broad region with deformation distributed among numerous faults and moderate-magnitude seismicity. However, the model is untested because most deformation occurs underwater, at poorly characterized faults of undetermined slip. Here we assess the diffuse-strain model analysing two active offshore fault systems associated with the most prominent seafloor relief in the region. We use pre-stack depth migrated seismic images to estimate, for the first time, the total Plio-Holocene slip of the right-lateral Yusuf and reverse Alboran Ridge structurally linked fault system. We show that kinematic restoration of deformational structures predicts a slip of 16 ± 4.7 km for the Alboran Ridge Fault and a minimum of 12 km for the Yusuf Fault. Thus, this fault system forms a well-defined narrow plate boundary that has absorbed most of the 24 ± 5 km Plio-Holocene Africa-Eurasia convergence and represents an underappreciated hazard, The authors acknowledge support from the Spanish Ministry of Economy and Competitiveness through the Complementary Action ESF TopoEurope TOPOMED (CGL2008-03474-E/BTE) and national project EVENT (CGL2006-12861-C02-02). L.G.P. was funded by the Spanish Ministry of Education, Culture and Sport through the FPU fellowship AP2012-1579 and a Short-Term Scientific Mission (COST-STSM-ECOST-STSM-ES1301-180814-045667) inside the COST Action ES1301. This study benefited from a Marie Skłodowska-Curie Individual Fellowship to L.G.P. (H2020-MSCA-IF-2017 796013), the project “MORPHOMED” (PID2019-107138RB-I00) funded by MCIN/SRA (State Research Agency/10.13039/501100011033), FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades/Projects (B-RNM-305-UGR18, A-RNM-508-UGR20 and P18-RT-3632), and acknowledges the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S) and C.R.R. project PID2019-109559RB-I00 of the Spanish “Ministerio de Ciencia e Innovación”. We thank the reviewers (Joao Duarte and anonymous) for their insightful comments. This work has been carried out within Grup de Recerca Consolidat de la Generalitat de Catalunya “Barcelona Center for Subsurface Imaging” (2017 SGR 1662), Peer reviewed

This is a contribution of the Barcelona Center for Subsurface Imaging.-- 18 pages, 13 figures, 3 tables, 2 appendixes, supplementary data https://doi.org/10.1093/gji/ggac087.-- Data availability: The DC code is available online at GitHub repository: https://github.com/ejimeneztejero/DC, under the GNU general public license v3.0, The purpose of marine seismic experiments is to provide information of the structure and physical properties of the subsurface. The P-wave velocity distribution is the most commonly modelled property, usually by inversion of arrival times or waveform attributes. In wide-angle seismic reflection/refraction (WAS) experiments, arrival times of seismic phases identified in data recorded by ocean bottom seismometers (OBS) are used to image relatively deep structures. Most WAS experiments have relatively low redundancy and produce robust velocity models of limited resolution. The shallow subsurface is also commonly studied with multichannel seismic (MCS) data recorded by towed streamers, a technique that is highly complementary to WAS. In this case, the recording of refractions as first arrivals is limited primarily by the streamer length and by features like water depth and the velocity structure and, in general, most refractions are masked by reflections and noise. However, MCS data of variable quality are available in many regions where no other data exist and previous work has shown that these data can also be used to retrieve velocity models through traveltime and full waveform inversion provided that first arrival information is properly extracted from the record sections. The most widely used tool to extract refractions as first arrivals from MCS recordings is the so-called downward continuation technique, which is designed for redatuming streamer field data to the seafloor. In this new virtual configuration, the early refractions transform to seismic phases that are becoming visible as first arrivals from nearly zero offset, facilitating their identification and use in traveltime tomography. However, there is limited literature, let alone available codes, to be used with the available MCS data sets. This work presents a user-friendly open source HPC software for redatuming 2-D streamer field data to the sea bottom for any seafloor relief. The main ingredient is the acoustic wave equation used backwards in time, allowing first the redatuming of the receivers and then the redatuming of the sources. Assessment tools are provided to evaluate the information available after redatuming for specific data acquisition configurations. Also, we present a step-by-step analysis that defines the most important features that influence the quality of the virtual, redatumed recordings, The work has been partially supported by project FRAME with reference CTM2015-71766-R and project ATLANTIS (PID2019-109559RB-I00), funded by the Spanish Ministry of Science, Innovation and Universities. ICM has also received funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S) of the Spanish Research Agency (AEI), Peer reviewed

This is a contribution of the Grup de Recerca 2017 SGR 1662 ‘Barcelona Center for Subsurface Imaging’ of the Generalitat de Catalunya.-- 16 pages, 8 figures, supporting information https://doi.org/10.1093/gji/ggad163.-- Data Availability: Synthetic magnetic models were produced using the freely available MAGPRISM software (https://sites.google.com/view/markkussoftware/gravity-and-magnetic-software/magprism). Magnetic forward models were computed using the GMSYS modelling package of Oasis montaj™ from Seequent (research license).-- This is a pre-copyedited, author-produced PDF of an article accepted for publication in Geophysical Journal International following peer review. The version of record [insert complete citation information here] is available online at: https://doi.org/10.1093/gji/ggad163, About half of the rifted margins purportedly formed by extension with minor magmatism. The conceptual models of those magma-poor systems are greatly influenced by the continent-to-ocean transition structure of the archetypal magma-poor West Iberia Margin. In the past, interpretation of magnetic data of West Iberia has been used to constrain conceptual rifting models, including the structure of the transition from the exhumed mantle domain to the oceanic crust formed at a spreading centre. However, uncertainties on geophysical data were generally not considered leading to overdetailed interpretations. We use synthetic magnetic modelling to show that magnetic data acquired at sea level cannot resolve subhorizontal lithological layering in deep-water continental margins. We then present new magnetic modelling guided by a refined velocity model of the wide-angle seismic IAM-9 profile that shows that the magnetic J-anomaly correlates with oceanic crust that abuts exhumed mantle across a vertical boundary. This well-constrained observation supports that seafloor spreading initiated abruptly, terminating mantle exhumation. Conventional wisdom dictates that the sudden efficient melt extraction relates to a mechanical threshold during lithospheric thinning and concomitant asthenospheric upwelling under which melt can migrate toward the surface. However, our results support that mantle melting creating oceanic crust was probably not driven by gradual lithospheric thinning and asthenospheric upwelling, but by seafloor spreading centre propagation that cut across the lithosphere, creating the abrupt structure, MN acknowledges support from Fundação para a Ciência e Tecnologia, I.P./MCTES through national funds (PIDDAC)—projects LISA (PTDC/CTA-GEF/1666/2020), UIDB/50019/2020-IDL and PTDC/CTA-GEO/031885/2017. CRR was supported by project FRAME (CTM2015-71766-R), ATLANTIS (PID2019-109559RB-I00), funded by the Spanish Ministry of Science and Innovation and ‘Severo Ochoa Centre of Excellence’ (CEX2019-000928-S) of the Spanish Research Agency (AEI), Peer reviewed

American Geophysical Union Meeting (AGU23), 11-15 December 2023, San Francisco, The J magnetic anomaly is a >1000 km long seafloor-spreading lineation ~125-120 Ma in the northern sector of the Central Atlantic crust in both the African and conjugate American plates. There, the J magnetic anomaly integrates the M3-M0 anomalies of the Cretaceous M-series, but displays anomalously high amplitude values of 200-400 nT, i.e. up to 20 times larger than similar age anomalies.

More intriguing is that the J magnetic anomaly appears to extend into the West Iberia rifted continental margin, whereas there is no clear similarly high-amplitude linear magnetic anomaly in the conjugate Canadian margin.

The origin of the J-magnetic anomaly in the central Atlantic is undisputedly oceanic but the cause for its high magnetic amplitude has not yet been explained.
The origin of the J-magnetic anomaly in the West Iberia margin is highly disputed, namely for its its age and origin (e.g. synrift magmatism or seafloor spreading), and even whether it represents the extension to the north of the oceanic J-anomaly or is an unrelated structure (with different age and origin).
We present a new geophysical dataset collected in 2022 across the J anomaly in the African plate that allows discussing the nature of the anomaly where it was first described and defined. Then, we compare the results with a new interpretation of the also called J magnetic anomaly off West Iberia.
We will provide new information and modelling regarding the origin of the high amplitude and discuss the similarities and differences between the anomalies in the African and Iberia plates to evaluate the possibility of a common origin of the magnetic lineations, This work was funded by the Portuguese Fundação para a Ciência e a Tecnologia (FCT) I.P./MCTES through national funds (PIDDAC) – UIDB/50019/2020- IDL. Support from FCT (PTDC/CTA-GEF/1666/2020), Spanish Ministry of Science and Innovation (CTM2015-71766-R, PID2019-109559RB-I00) and Spanish Research Agency (CEX2019-000928-S) is also acknowledged, Peer reviewed

25 pages, 14 figures, 2 tables, supporting information https://doi.org/10.1029/2022JB026180.-- Data Availability Statement: The SO-23 and SO-49 seismic field data can be requested from the www.geo-seas.eu data portal. Borehole Silangan-1 is available through the Energy Data Centre of the Philippines (https://www.doe.gov.ph/edcp). Supporting Information S1 includes supplementary Figures S1–S7, showing the uninterpreted seismic profiles (Cadenas & Ranero, 2024). Seismic processing was done with Claritas (https://www.petrosys.com.au/claritas/) and Radex softwares (https://radexpro.com/) and interpretation with the Kingdom Suite software (https://kingdom.ihs.com/), provided by IHS through an academic license. ArcGIS (https://www.esri.com) was used to construct maps, We discuss the tectonic structure, seismic stratigraphy and evolution of the NW Sulu Sea using reprocessed 2D reflection profiles. The NW Sulu Sea is located between the Palawan continental shelf and the Cagayan Ridge and represents the northern part of the Sulu Sea, a marginal sea resulting from Paleogene extension and subsequent Neogene contraction due to convergence between the Palawan and the Philippine blocks. The basin consists of six seismo-stratigraphic units overlying crystalline basement. Syn-orogenic depocenters contain calibrated Middle Miocene to, possibly, Lower Miocene units, while rift-related depocenters consist of uncalibrated but tentatively dated Paleogene to Lower Miocene units. Thickness and depth maps of the main units and bounding horizons differentiate the Piedra-Blanca and the Rasa domains, separated by the NW-Sulu-Break major tectonic structure. Fault-bounded rift-related depocenters are strongly segmented. We interpret that NW-SE and NE-SW trending zones accommodate shape and trend variations of these depocenters. We suggest that these zones may link rift segments, recording different extensional deformation. Miocene thrusting and folding in the Piedra-Blanca Domain and mudflow with associated gravitational structures in the Rasa Domain influenced the deposition of syn-orogenic units. Rift structures inherited from rift segmentation may have conditioned the style and distribution of contractional deformation during the subsequent incipient reactivation during contraction. In the context of SE Asia, our results support that the timing of rifting of the NW Sulu Sea overlaps with the opening of the South China Sea and the North Palawan margin, which may indicate a common geodynamic driving force triggering extension, This work and the seismic processing were supported by the Geomargen 5-SE Asia project, an academic-industry partnership between the CSIC and REPSOL S.A. We thank the German Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) for providing the raw field seismic data and Ennio Piazza for seismic processing. This work is a contribution of the “Grup de Recerca Consolidat de la Generalitat de Catalunya” Barcelona-CSI (2017SGR1662). This work acknowledges the “Severo Ochoa Centre of Excellence” accreditation (CEX2019-000928-S). C.R.R. was further supported by the ATLANTIS project (PID2019-109559RB-I00) from the Spanish Ministry of Science and Innovation. The Marie Skłodowska-Curie grant agreement No 895895, project SUBIMAP, funded by the European Union's Horizon 2020 research and innovation programme, further supports and funds P.C. and this work. P.C. acknowledges the Portuguese Fundaçao para a Ciência e a Tecnologia (FCT) I.P./MCTES through national funds PIDDAC-UIDB/50019/2020, UIDP/50019/2020, and LA/P/0068/2020, Peer reviewed

European Geosciences Union General Assembly (EGU23), 24-28 April 2023, Vienna, Austria.-- 1 page, The conceptual models of magma-poor rifted margins are greatly influenced by the continent-to-ocean transition structure of the archetypal magma-poor West Iberia Margin. Some previous works with West Iberia magnetic data have been used to constrain the structure and interpret the transition from the exhumed mantle domain to the oceanic crust formed at a spreading center. However, it is found that the resolution uncertainty of the geophysical data was generally overlooked, leading to over-detailed interpretations. In this work we use synthetic magnetic modelling to show that magnetic data acquired at sea-level cannot resolve sub-horizontal lithological layering in deep-water continental margins. Then, we present a new magnetic model guided by a refined velocity model of the wide-angle seismic IAM-9 profile in the Iberia Abyssal Plain. This new model supports that the J-anomaly is caused by a ~6 km thick oceanic crustal structure with locally increased magnetization compared to regular oceanic crust. This J-anomaly crust abuts the exhumed mantle across a nearly vertical boundary, and is the oldest accreted oceanic crust. These results support that mantle exhumation was abruptly terminated by the accretion of oceanic crust. Mantle melting creating oceanic crust was probably not driven by gradual lithospheric thinning and asthenospheric upwelling, but may be the result of seafloor spreading center propagation cutting across the lithosphere and creating the abrupt structure, This work was funded by the Portuguese Fundação para a Ciência e a Tecnologia (FCT) I.P./MCTES through national funds (PIDDAC) – UIDB/50019/2020- IDL. Support from FCT (PTDC/CTA-GEF/1666/2020), Spanish Ministry of Science and Innovation (CTM2015-71766-R, PID2019-109559RB-I00) and Spanish Research Agency (CEX2019-000928-S) is also acknowledged, Peer reviewed

29 pages, 14 figures, supporting information https://doi.org/10.1029/2023TC008184.-- Data Availability Statement: The data set interpreted here is public and available from the Brazilian National Agency of Petroleum, Natural Gas and Biofuels (ANP). Public data set available can be consulted: https://geomaps.anp.gov.br/geoanp/. For more information about requesting data contact: helpdesk@anp.gov.br. The uninterpreted images of the seismic data are publicly available at https://figshare.com/articles/figure/Equatorial_Database/24208308, The Brazilian Equatorial Margin (BEM) is interpreted as a transform margin, where the last segment opened during Gondwana rifting. However, margin evolution, and break-up age remain unconstrained. We interpret >10k km of crustal-scale seismic images extending along ∼600 km of the margin calibrated with drillholes. We determine the style and timing of tectonics across the rift system. We link changes in crustal-scale structure and age of sediment deposits to interpret variations with the style of extension and intensity of thinning across the BEM. Observations support a rift evolution where deformation is initially distributed forming a shallow basin, subsequently focusses, and later migrates basin-ward forming the deep-water domain. We interpret that tectonic activity started ∼140–136 Ma and stopped earlier in the shallow basin causing minor thinning, than in the deep-water domain with a ∼60 km wide area with 4–8 km thick crust extended in Late Aptian to Early Albian (116–110 Ma). Constraints from seismic and drilling help define an abrupt continent to ocean transition (COT) where continental crust may be abutted by oceanic crust, and breakup occurred at early Albian time. Basin sedimentation from the onset to the Late Aptian is continental, indicating an isolated environment disconnected from Atlantic oceans. During late-most Aptian to Early Albian basin sedimentation changes and indicates a comparatively rapid marine water infill. Rifting of the BEM is not dominated by transcurrent deformation as previously inferred, with strike-slip faulting limited to comparatively small sectors, whereas most of the margin extended by normal faulting deformation, C.R. R. acknowledges the support of the“ Severo Ochoa Centre of Excellence” accreditation (CEX2019‐000928-S) and the ATLANTIS project (PID2019‐109559RB‐I00) from the Spanish Ministry of Science and Innovation. This work is a contribution of the Barcelona Center for Subsurface Imaging that is a Grup de Recerca 2021 SGR 00429 of Generalitat de Catalunya, Peer reviewed

This work is a contribution of the Barcelona CSI that is a Grup de Recerca 2021 SGR 00429 of Generalitat de Catalunya.-- 13 pages, 9 figures, 1 table, supplementary data https://doi.org/10.1093/gji/ggaf136.-- Data Availability: The KVP code is openly available at https://github.com/B-CSI/kvp, including examples to run the package. Python implementations of FilterPicker and PS-Picker were obtained from their respective repositories at https://github.com/mbagagli/filterpicker (Bagagli 2022) and https://github.com/WayneCrawford/pspicker. PhaseNet and its pre-trained model are available at https://github.com/AI4EPS/PhaseNet. We utilized ObsPy (Krischer et al. 2015) for some data processing and analysis tasks. All figures were produced using the MatPlotLib package (https://matplotlib.org/stable/index.html). The IGN catalogue is accessible online at https://www.ign.es/web/ign/portal/sis-catalogo-terremotos. Data from the OT (Villaseñor et al. 2021) and SAFE (Ugalde et al. 2023) experiments are available from the authors on reasonable request.-- DIGITAL.CSIC https://doi.org/10.20350/digitalCSIC/18194, Automatic event detection and phase picking are critical for processing the large volumes of data produced by modern seismological instrumentation. Accurate picking is especially challenging in Distributed Acoustic Sensing (DAS) recordings, where data quality can significantly vary along segments of the fibre due to localized environmental noise and coupling issues, reducing signal-to-noise ratios (SNR). Similarly, Ocean Bottom Seismometer (OBS) data quality also suffers from these issues. To improve accuracy under diverse conditions, we developed a novel multiband kurtosis-based picking algorithm, Kurtosis-Value-Picker (KVP), that enhances phase picking for both impulsive and emergent seismic signals. Our approach uses characteristic functions (CFs) calculated with sliding windows across multiple frequency bands. Triggers are identified based on localized kurtosis jumps over a few samples, providing greater sensitivity to emergent signals than traditional finite-difference methods. Each individual CF has its own set of triggers, adding flexibility to phase picking and retaining spectral information. We validate the KVP algorithm using earthquake data recorded with DAS on two land and submarine fibre-optic cables, as well as OBS data. We also compare its performance with a widely cited, kurtosis-based algorithm, the widely used FilterPicker algorithm and the well-known PhaseNet model, using impulsive signals on nearby DAS channels as a ground truth for emergent arrivals. Our results demonstrate that KVP provides accurate picks and is suitable for complex seismic data sets, HL acknowledges the grant PRE2021-098838 funded by the Spanish Ministry of Science and Innovation MCIN/AEI/0.13039/501100011033. Funding for this project was provided through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S-21-2), the European Union NextGenerationEU/PRTR Program under projects PSI (ref. PLEC2021-007875) and TREMORS (ref. CPP2021-008869), the MCIN/AEI under project GUANCHE (ref. PID2020-114682RB-C31) and ATLANTIS (ref. PID2019-109559RB-I00) and the CSIC contract SAFE with Telxius Cable España, S. L. (ref. 20233069), Peer reviewed

13 pages, 11 figures, 1 table, supplementary data https://doi.org/10.1093/gji/ggaf137.-- Data Availability: The codes used in this study are available at GitHub repository under the GNU general public license v3.0:
The new DC-WAS code (Jimenez-Tejero et al. 2024) placed at github repository: https://github.com/ejimeneztejero/DC_WAS.
The 2-D code version for traveltime tomography used to obtain the results in this study (https://github.com/ejimeneztejero/TOMO2D), and our 3-D version (https://github.com/ejimeneztejero/TOMO3D_dev), Controlled-source marine seismic experiments are key in advancing our understanding of the Earth’s subsurface structure to study tectonic, magmatic, sedimentary and fluid flow processes. Joint acquisition of wide-angle seismic (WAS) and multi-channel seismic (MCS) streamer data stands as the most robust approach for marine exploration, however effectively mapping subsurface structure remains challenging. The lack of identifiable refractions as first arrivals at short offsets in WAS data creates shallow subsurface illumination gaps up to 6–8 km offsets around Ocean Bottom Seismometers or Hydrophones. This inadequate ray coverage, more pronounced in areas with deeper water column and lower seabed velocities, limits the performance of Travel Time Tomography (TTT) techniques. Velocity determination in the sedimentary layer and reflector location are affected, and errors propagate to deeper layers. This study integrates Downward Continuation (DC) to WAS data. Similarly to our former study where DC is applied to MCS data, redatuming WAS data involves solving the acoustic wave equation backward in time. This process virtually repositions the sources to the seafloor, revealing previously masked near-seafloor refractions as first arrivals. This transformation significantly enhances ray coverage in the shallow subsurface, leading to more accurate determinations of both seismic velocity and reflector geometry. By bridging theoretical concepts with a real data application, this study demonstrates the optimization of field seismic data for improved TTT results. This methodology is particularly beneficial for deep water exploration where spatially coincident WAS and MCS are jointly inverted. In such scenarios, DC-processed WAS data provides the refracted phases key for velocity determinations, and that are typically not present in MCS data due to insufficient streamer length relative to the water column depth. Additionally, we contribute to the community by releasing our open-source, High-Performance Computing software for WAS data redatuming, This is a contribution of the “Grup de Recerca Consolidat de la Generalitat de Catalunya” Barcelona Center for Subsurface Imaging (2017 SGR 1662). The work has been supported by projects CONNECT with reference PID2021-128851OA-I00, ATLANTIS (PID2019-109559RB-I00) and THREAT (PID2021-128513OA-I00), funded by the Spanish Ministry of Science and Innovation. ICM has also had funding support of the–Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI), Peer reviewed

Four OBS are provided in the input folder, and the parfile. Readme explains how to run the code with this sample data., The work has been supported by projects CONNECT with reference PID2021-128851OA-I00, ATLANTIS (PID2019-109559RB-I00) and THREAT (PID2021-128513OA-I00), funded by the Spanish Ministry of Science and Innovation. ICM has also had funding support of the–Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI), Peer reviewed

17 pages, 9 figures, supporting information https://doi.org/10.1029/2025JB031304.-- Data Availability Statement: The raw data used for P-wave travel-time tomographic inversion in this study are available at Zhang (2023), The oceanic lithospheric structure is key to understanding the processes related to the interplay between tectonics and magmatism from the end of rifting to the onset and cessation of seafloor spreading. In the oceanic basin of the South China Sea (SCS), the Southwest Sub-basin (SWSB) is the last-opening segment before the abandonment of seafloor spreading. The SWSB shows a V-shaped geometry associated with the SW-ward propagation of the spreading center during the opening. Here, we present a 540-km-long wide-angle seismic profile along a seafloor-spreading flow-line in the central sector of the SWSB. A joint refraction and wide-angle reflection travel-time tomography provides a P-wave velocity (Vp) model of the crust and uppermost mantle. Continental break-up produced asymmetric conjugate margins, abutted by a typical oceanic crust with a two-layer Vp structure. The distinct vertical velocity gradients in the upper and lower crust, and a clear Moho, indicate a magmatically-dominated oceanic system. In contrast, oceanic crust <19.2 Ma displays no Moho interface and a Vp structure indicating reduced magmatism and increased tectonic extension. Anomalously slow Vp structure under the median valley indicates serpentinized mantle resulting from enhanced faulting during the final opening phase. The spatial variation in Vp structure reflects two main temporal stages of the SWSB seafloor spreading before cessation. Previous results of plate kinematics reconstructions appear to support that the transition from magmatically robust to increased tectonics and final cessation of seafloor spreading in the SWSB might relate to the subduction of the proto-SCS, This work was financially supported by National Natural Science Foundation of China (Grant U20A20100, 91958212, 41730532, 42106079), and the special fund of South China Sea Institute of Oceanology of the Chinese Academy of Sciences (SCSIO2023HC08).[...] C.R.R. acknowledges the support of grant CEX2024-001494-S funded by AEI 10.13039/501100011033, and ATLANTIS (PID2019- 109559RB-I00) project funded by the Spanish Ministry of Science, Innovation and Universities. [...] Open Access funding enabled and organized by Projekt DEAL, Peer reviewed

19 pages, 8 figures, supporting Information https://doi.org/10.1029/2024JB030564.-- Data Availability Statement: The OBS data used in this work are available at Grevemeyer et al. (2024) https://doi.org/10.1594/PANGAEA.973502, A seismic transect across the Xisha Trough failed rift provides information on processes active during the opening of the South China Sea (SCS). The rift basement gradually thins at the conjugate flanks from ∼25 to 15 km toward the central sector, where it abruptly thins to ∼10–6 km in thickness. The seismic velocity model supports that 6.5 km/s velocity separates an upper from a lower crust layer, where Vp reaches 7.1 km/s above Moho. The upper crust extends across the entire rift, but the lower crust layer does not occur in the thin crust of the central sector, which is underlain by mantle with anomalously low Vp, indicating serpentinization. Changes in tectonic structure mimic the Vp distribution. The rift flanks have comparatively small faults associated to gradual thinning, whereas the central sector has larger faults that possibly reach the mantle. The faulting in the central sector thus indicates whole-crust embrittlement, which possibly led to synrift mantle serpentinization. Despite the weaker rheology, serpentinized mantle did not result in the development of low-angle faulting or continental break-up. Furthermore, the rift overall thinning and faulting structure is asymmetric with respect to the rift center, supporting an initial widespread moderate extension creating the flanks. When extension thinned the crust to <15 km, the whole crust was brittle and deformation first focused and subsequently laterally migrated to create the central sector. The continental Xisha Trough rift evolution is similar to classical magma-poor margins, but synrift magmatism described in adjacent regions indicate abrupt segmentation of the rift system, This study was supported by 1:250,000 Dalian marine regional geological survey project (DD20243125); the State Scholarship Fund from the China Scholarship Council, China (202204910357). C.R. Ranero and W. Wang during his stay at the Barcelona Center for Subsurface Imaging (CSI), were supported by the “Severo Ochoa Centre of Excellence” accreditation (CEX2019-000928-S) and the ATLANTIS project (PID2019-109559RB- I00) from the Spanish Ministry of Science and Innovation. This is a contribution of the Barcelona CSI that is a Grup de Recerca 2021 SGR 00429 of the Generalitat de Catalunya. Dongdong Dong is supported by the National Key R&D Program of China (2022YFC2808305, 2022YFC2803501) and the Taishan Scholars Program (Grant tsqn202306283), Peer reviewed

Wide-angle seismic data acquired across the Xisha Trough in the South China Sea. The data were acquired with 10 Ocean Bottom Hydrpobones from GEOMAR in 1996. The records are reduced to 6 km/s, relocated, and filtered using a bandpass filter, and wiener predictive error filter. Navigation is included as an ASCII file with longitude and latitude of shots, China Scholarship Council (CSC), grant/award no. 202204910357. Spanish Ministry of Science, Innovation and Universities (MICINN), grant/award no. PID2019‐109559RB‐I00: ATLANTIS, C.R. Ranero and W. Wang during his stay at the Barcelona Center for Subsurface Imaging (CSI), were supported by the “Severo Ochoa Centre of Excellence” accreditation (CEX2019-000928-S), Peer reviewed

17 pages, 7 figures, supporting information https://doi.org/10.1029/2024JB030874.-- Data Availability Statement: Wide-angle seismic data (Grevemeyer et al., 2024 https://doi.org/10.1594/PANGAEA.973717) and multichannel seismic data (Ranero et al., 2024 https://doi.org/10.1594/PANGAEA.973759) presented in this study can be found in PANGAEA. Travel-time tomography code TOMO2D can be found in Zenodo (Jimenez-Tejero, 2025 https://doi.org/10.5281/zenodo.15591999), The J magnetic anomaly in the Central Atlantic has 10 times larger amplitude than surrounding seafloor-spreading magnetic lineations and is often associated with thick oceanic crust formed by excess magma. The anomaly has also been identified in the southern North Atlantic, where it has been linked to the onset of seafloor spreading, challenging traditional 2D models of lithospheric break-up offshore Iberia. These findings underscore the importance of constraining the crustal structure along the J anomaly to fully understand its genetic processes and geodynamic significance. Yet, the crustal structure in the Central Atlantic, where the anomaly is strongest, remains poorly defined by low-resolution legacy seismic data. We present wide-angle and multichannel seismic data from the 2022 ATLANTIS survey across the J anomaly at ∼31°N in the Central Atlantic. We use 2D seismic tomography to invert for P-wave (Vp) and S-wave (Vs) velocities. Results reveal significant lateral variations in igneous basement thickness and seismic velocities, contradicting the idea of uniformly thick crust. The peak of the anomaly is not aligned with the thickest segment (10 km) but with a region where oceanic layer 3 exhibits the fastest Vp and Vs. Variations in basement thickness are accompanied by lateral differences in Vp/Vs, reflecting changes in composition and/or basement fracturing. These findings suggest diverse crustal accretion processes, influenced by a fertile mantle source and short-term mantle temperature differences during the formation of the J anomaly, This work has been funded by the Spanish Ministry of Science and Innovation MCIN/AEI under project ATLANTIS (ref. PID2019-109559RB-I00). [...] This work has benefited from additional funding from projects CONNECT (PID2021-128851OA-I00) and THREAT (PID2021-128513OA-I00) both funded by MICIU/AEI/10.13039/501100011033 and by ERDF/EU. ICM has also had funding support of the “Severo Ochoa Centre of Excellence” accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI). Marta Neres acknowledges FCT (Fundação para a Ciência e Tecnologia) for support through project LISA–https://doi.org/10.54499/PTDC/CTA-GEF/1666/2020., Peer reviewed

Wide-Angle Seismic (WAS) data acquired across ATLANTIS-I profile in 2022 at 31ºN Central Atlantic. The seismic data were recorded with 22 ocean bottom hydrophones (OBH) from GEOMAR (Germany), deployed every ~8 km along the transect. Processing of OBH data involved receiver relocation using an in-house Metropolis-Hasting grid-search algorithm, a Wiener predictive error filtering, and a band pass filter, Spanish Ministry of Science, Innovation and Universities (MICINN), grant/award no. PID2019‐109559RB‐I00: ATLANTIS. Agencia Estatal de Investigación (España) CEX2019-000928-S, Navigation file: shot number, year, day, and time of acquisition, and longitude and latitude in degrees. SEGY files of each OBH: Seismic records have a velocity reduction of 8 km/s, Peer reviewed

Pre-stack time-migrated seismic section across ATLANTIS-I profile in 2022 at 31ºN Central Atlantic. The seismic data were acquired with a seismic source that consisted of two sub-arrays of airguns with total capacity of ~4000 c.i., towed from the stern of the boat at 15 m of depth, and fired every 100 m. Seismic data were collected with a 240-channel, 3-km-long streamer towed from the stern of the boat at 19 m of depth. Data processing included streamer geometry for common mid-point geometry, a two-window statistical Wiener deconvolution, velocity analysis every 5 km, stacking, and time migration using a finite-differences algorithm and a geological meaningful Vp model. Final display is shown with a Butterworth minimum phase band pass filter (3-60 Hz) and a median automatic gain control (AGC) with a 2 second sliding window to balance amplitudes, Spanish Ministry of Science, Innovation and Universities (MICINN), grant/award no. PID2019‐109559RB‐I00: ATLANTIS. Agencia Estatal de Investigación (España) CEX2019-000928-S, Peer reviewed

20 pages, 10 figures, supporting information https://doi.org/10.1029/2025JB032857Digital Object Identifier (DOI)
.-- Data Availability Statement: The data sets are available upon request to the Brazilian National Agency of Petroleum, Natural Gas, and Biofuels (ANP). Uninterpreted and interpreted seismic images are available at (Fonseca et al., 2025). Please refer to this article and to the repository DOI to reproduce any seismic image. Maps were generated with the open-source QGIS software (QGIS Development Team, 2024), We have investigated from rift inception to break up, the tectonic structure, spatial segmentation, and temporal evolution along ∼600 km of the East-Ceará and Potiguar basins of the Brazil Equatorial Margin. We have determined the initial rift configuration, the onset of the formation of the continental margin, and its structural evolution into a Southern, Central and Northern Segments. A distinct tectonic structure and evolution, limited by abrupt boundaries, characterize each segment. The segmentation boundaries define linear trends in the basement that extend from under the continental shelf to the deep-water domain. The trend of the segment boundaries appears to delineate flow-lines of the opening direction. The geometry of the boundaries, and available fault and dike patterns, provide information on the orientation of paleo-stresses. We integrated the distribution, geometry and age of structures to produce an evolutionary model and related it to plate kinematics. The initial Phase 1 deformation occurred in a four-arms configuration, each with different opening direction. This configuration was modified during a kinematic reorientation, causing two arms to stop opening during Phase 2. Phase 2 extension focused along two arms, creating a margin-type structure, which readjusted internal deformation into a Central, Northern and Southern Segments. Rift extension continued adapting to a gradual kinematic change into a Phase 3, when the Southern Segment developed a transcurrent fault system. Margin extension ended during Phase 4 with the initiation of spreading cells with a distribution mimicking the main rift segmentation, which remained as segmentation giving rise to oceanic fracture zones, C.R.R. acknowledges the support of the “Severo Ochoa Center of Excellence” accreditation (CEX2019-000928-S) and the ATLANTIS project (PID2019-109559RB-I00) from the Spanish Ministry of Science, Innovation and Universities. This work is a contribution of the Barcelona CSI, that is, a Grup de Recerca 2021 SGR 00429 of the Generalitat de Catalunya, Peer reviewed

We also uploaded JPEG in high resolution of the interpreted seismic lines.
The survey campaign that collected this dataset occurred between 26-12-00 21-06-01 by WesternGeco Services of Seismic Ltda. The signal was recorded on a 4050 m long, 324 channels Syntrac streamer. Industry by the same acquisition company processing 183 includes statistical deconvolution, radon filter multiple attenuation, pre stack time migration. The lines presented are distributed on the offshore Potiguar and Ceará Basins (Equatorial Atlantic), between Romanche and Chain Fracture Zones, covering continental shelf, slope and deep basin of the Equatorial Brazilian Margin. To request public dataset from offshore sedimentary basins in Brazil please consult helpdesk@anp.gov.br for offshore seismic campaigns. To visualize available data please check:
https://geomaps.anp.gov.br/
If you reproduce one or more images please refer to this repository, to the original article and also to ANP, The data includes 7 images from 9 seismic lines available and public seismic images provided by the Brazilian National Agency of Petroleum (ANP) via Exploration and Production Data Bank for educational and research purposes only. All the seismic profiles are provided already processed (post-stack) and are used for interpretation. The repository contains seismic lines from Figures 2 and 4- 8 from the paper subbimited in Journal of Geophysical Research: Solid Earth.
Seismic line 6473: Figure 2
Seismic line 6172: Figure 5
Seismic lines 6184, 6196, 6208, 6232: Figures 5a-5d
6136 (Figure 6)
6124 (Figure 7)
6100 (Figure 8), Brazilian National Agency of Petroleum, Natural Gas and Bioefuels (ANP) - public dataset., C.R.R. acknowledges the support of the “Severo Ochoa Center of Excellence” accreditation (CEX2019-000928-S) and the ATLANTIS project (PID2019-109559RB-I00) from the Spanish Ministry of Science, Innovation and Universities, Peer reviewed

This dataset consists of four file folders: OBS_20231215, OT_20211026, SAFE_20231113, and SAFE_20231215.
The OT_20211026 and SAFE_20231113 folders are still pending upload due to their large size., This research focuses on improving automatic event detection and seismic phase picking in large and complex data sets generated by modern instruments, particularly Distributed Acoustic Sensing (DAS) and Ocean Bottom Seismometers (OBS). The authors address a major limitation of these systems: data quality often varies strongly along the fibre or between stations because of environmental noise, poor coupling, and low signal-to-noise ratios, which makes accurate picking especially difficult for emergent arrivals. To overcome this problem, they developed a new multiband kurtosis-based algorithm called Kurtosis-Value-Picker (KVP), designed to enhance the detection of both impulsive and emergent seismic signals. The method computes characteristic functions in several frequency bands using sliding windows and identifies triggers from localized jumps in kurtosis, which makes it more sensitive to subtle arrivals than traditional approaches. The algorithm was validated with earthquake records from land and submarine DAS cables as well as OBS data, and its performance was compared with FilterPicker and PhaseNet. The results show that KVP provides accurate and robust picks across diverse recording conditions, preserves useful spectral information, and is well suited for the analysis of complex seismic data sets, Grant PRE2021-098838 funded by the Spanish Ministry of Science and Innovation MCIN/AEI/0.13039/501100011033; European Union NextGenerationEU/PRTR Program under projects PSI (ref. PLEC2021-007875) and TREMORS (ref. CPP2021-008869), the MCIN/AEI under project GUANCHE (ref. PID2020-114682RB-C31) and ATLANTIS (ref. PID2019-109559RB-I00) and the CSIC contract SAFE with Telxius Cable España, S. L. (ref. 20233069), This work contributes to the Institut de Ciències del Mar "Severo Ochoa Centre of Excellence" accreditation CEX2024-001494-S funded by AEI 10.13039/501100011033 of the Spanish Ministry of Science and Innovation, The data provided correspond to the datasets used to generate the figures presented in the associated research paper. This is a subset of the full experimental datasets, selected to ensure reproducibility of the results shown in the publication. The datasets are organized into experiment-specific folders, each corresponding to a deployment or acquisition campaign: • OBS_YYYYMMDD – Ocean Bottom Seismometer (OBS) data • OT_YYYYMMDD – DAS dataset from OT experiment • SAFE_YYYYMMDD – DAS dataset from SAFE experiment All timestamps are in UTC. 1. OBS Data (miniSEED format) Files follow the structure: <station>.<channel>.<YYYY>.<DAY>.<HH>.<MM>.<SS>.mseed where: • <station> – OBS station identifier (e.g., obs02) • <channel> – Seismic component: o EHZ – Vertical o EH1 – Component 1 o EH2 – Component 2 o EHH – Hydrophone • <YYYY> – Year • <DAY> – Day of year • <HH.MM.SS> – Start time (UTC) • .mseed – miniSEED seismic format Organization: • Continuous full-day recording • One file per component 2. DAS Data - OT Experiment (HDF5 format) Files follow the structure: OT_<YYYYMMDD>_<NN>.h5 where: • <YYYYMMDD> – Acquisition date • <NN> – Time segment • .h5 – HDF5 format Organization: • Full-day acquisition split into short time segments (15 minutes per file) • Total of 95 files covering the day 3. DAS Data – SAFE Experiment (Event-based and Continuous) a) Event dataset (15/12/2023) SAFE_<YYYYMMDD>.h5 • Single file containing the full event waveform b) Continuous dataset (13/11/2023) SAFE_<YYYYMMDD>_<NN>.h5 where: • <NN> – Time segment Organization: • Full-day recording split into 15-minute segments • Total of 95 files covering the entire day, Peer reviewed