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The NEARESTproject (Integrated observations from NEAR shore sourcES of Tsunamis: towards an early warning system) aimed at the identification and characterization of potential near-shore sources of tsunamis in the Gulf of Cadiz. This area is well known from the catastrophic earthquake and tsunami that destroyed Lisbon and several other places mainly along the EastAtlantic coast on November 1st, 1755. One of the project's work packages dealed with monitoring of recent seismic activity in the Gulf of Cadiz area. For this purpose 24 broadband ocean-bottom seismometers (OBS) from the German DEPAS instrument pool were deployed for 11 months in addition to the GEOSTAR multi-parameter deep-sea observatory and two temporary land stations in Portugal. The GEOSTAR observatory and the 24 OBS were deployed and recovered during two expeditions with RV Urania in 2007 and 2008. The OBSs consist of three‐component Guralp CMG‐40T‐OBS seismometers and HighTech HTI‐04‐PCA/ULF hydrophones. A wide range of signals was recorded, ncluding teleseismic, regional and local earthquakes, and low‐frequency (∼20 Hz) vocalization of fin whales. The GEOSTAR observatory was again deployed between 2009 and 2011. The Portuguese temporary land station PDRG was additionally recording during the NEAREST project. Originally, the position of recovery on deck was taken to calculate the mean coordinate of the OBS at depth from deployment and recovery coordinates. In most cases the difference in coordinates between deployment and recovery is very small (table 3 and 4 in Carrara et al., 2008). For two stations, the location at the seafloor could be measured by triangulation (Carrara et al., 2008). Due to experience of other experiments over the years, we finally suggest to use the deployment coordinates as the station coordinates for all stations that could not be tri-angulated. The clocks were synchronized with GPS time before the deployment and if possible again after the recovery. Unfortunately, most of the batteries were empty at the end of the recording period. That either made it impossible to realize the second synchronisation (skew time measurement) or in some case also caused erroneous synchronisations. Therefore, the internal clock drift was estimated by ambient noise analysis (Corela, 2014). The internal clock drifts were corrected using a linear interpolation method. Generally, the data quality is very good, especially for the intended study of local and regional earthquakes. Studies relying on wideband seismological recordings can also be carried out. The sensor package and noise conditions hamper the use for broadband and very broadband applications. Unfortunately, also not all channels operated properly, therefore hampering the use of multi-component methods for the relevant stations. We thank the captain E. Gentile, crew, G. Carrara, and all participants of the R/V URANIA expeditions in 2007 and 2008. We are grateful to all people and institutions involved in the NEAREST project. Waveform data is available from the GEOFON data centre, under network code 9H.
Here we are sharing our code, tutorials and examples used to interpret geological structures (e.g. faults, salt bodies and horizones) in 2-D and/or 3-D seismic reflection data using deep learning. The repository is organised in a series of tutorials (Jupyter notebooks) with increasing degree of difficulty. We show step-by-step how to: (1) load seismic data, (2) train a model and (3) apply the model to map different geological structures. You can find a few visual examples on our poster and more technical details in our preprint.
During the 2018 “Mackenzie Delta Permafrost Field Campaign” (mCan2018), a test campaign within the “Modular Observation solutions for Earth Systems” (MOSES) program, ambient seismic noise recordings at the sea bottom were acquired along two 300 m long transects from the shoreline to shallow marine area close to Tuktoyaktuk Island (Canada). In total, 21 measurements were taken. Raw data is provided in proprietary “Cube” format and standard mseed format.
BEAR ISLAND (The Dynamic Continental Margin Between the Mid-Atlantic-Ridge System (Mohns Ridge, Knipovich Ridge) and the Bear Island Region) is an interdisciplinary project exploring the stress conditions and sources, and the dynamics and deformation characteristics of the continental margin between the Mid-Atlantic Ridge and Bear Island from its top sedimentary cover to its imprint in the upper mantle. In this region the margin includes an extremely thick sedimentary wedge and steep slopes, with at least one major paleo-fracture zone cutting through the wedge. Recent studies in this area indicate very low seismic velocities in the lithosphere and the stress field undergoes an extensional-compressional transition. It is therefore of particular interest to understand the structural architecture, the stress and the dynamics of the whole region because of its natural hazard exposure and the processes involved in the formation of the margin and the opening of the North Atlantic. To achieve this, deep seismic sounding data, as well as records from temporary broadband installations, supplementary to data from existing seismic stations in the region were collected. A key element of the project was the operation of a long-term network of broadband ocean-bottom seismometers (OBS). Additionally, two new broadband seismometers and a small temporary seismic array with 13 sensors were operated. Active seismic refraction/reflection experiments were conducted along two profiles crossing the region and recorded with additional short period OBSs and land stations. Twelve broadband ocean-bottom seismometers (OBS) from the German Instrument Pool of Amphibian Seismology (DEPAS) were deployed as part of this network with RV Horyzont II in September 2007. They were distributed on the Barents shelf, the slope and the deep sea near the Mid-Atlantic Ridge. Nine instruments could be recovered in August 2008 with RV Horyzont II. One instrument was fished before, one was destroyed during recovery and one got lost. Seven stations recorded data for the full deployment period; two stations have no skew value. The time correction for these stations was estimated by noise cross-correlations. Based on previous experiments, the accuracy of the positions is estimated to 500 m. Waveform data is available from the GEOFON data centre, under network code 9C.
Project SWEAP (Southwest Indian Ridge Earthquakes and Plumes), a collaborative effort led by the Alfred-Wegener-Institute, installed a network of 10 broad-band ocean bottom seismometers (OBS) along the ultraslow-spreading Oblique Supersegment of the Southwest Indian Ridge. The presented data set covers the continuous records of 8 stations of the network provided by the DEPAS instrument pool. One station of the original network could not be recovered, another one did not return data. The instruments were spaced at roughly 15 km intervals in a triangular shape network to either side of the rift axis covering about 60 km along axis between 13°E and 13.8°E and 60 km across axis between 52°S and 52.6°S. The determination of the OBS positions is described by Schmid et al. (2016). The network design was optimized for detecting and locating deep seismicity in the area. The rift valley was filled with soft silica ooze, producing considerable delay of S-phases at selected stations. Instrument deployment started during RV Polarstern cruise ANT-XXIX/2 on December 05 2012. Instrument recovery was completed during RV Polarstern cruise ANT-XXIX/8 on November 26 2013. 5 Refraction seismic lines were acquired by RV Polarstern cruise ANT-XXIX/8 from November 17 to 19 in 2013. All OBS could be synchronized with the GPS clock upon recovery such that skew values describing the clock drift are available for all stations. The non-linear clock drift of station SWE05 was determined by means of noise cross-correlations and applied to the data set. All other stations show a linear drift, which was corrected.
This dataset contains subaquatic passive seismic recordings taken in September 2021 at 88 locations off Tuktoyaktuk Island as well as in a small lake (“Lake 3”) between the villages of Tuktoyaktuk and Inuvik, Northwest Territories, Canada. The measurements were part of the “Mackenzie Delta Permafrost Field Campaign” (mCan2021) within the “Modular Observation solutions for Earth Systems” (MOSES) program. Data is from a seismic intermediate-bandwidth seismic sensor lowered for few minutes to the bottom of the sea and lake, respectively, and from underwater short-period sensors deployed for a few days. The aim of the study was to determine the depth of the subaquatic permafrost (local lake and oceanic locations). Raw data is provided in proprietary “Cube” format and standard mseed format.
This project investigates the crust and upper mantle along a north-south oriented, about 350 km long profile from around the town of Ringkøbing in western Jutland to south of Hamburg in northwestern Germany, with a focus on teleseismic receiver functions and seismic tomography. A number of tectonic processes have affected the crust and uppermost mantle beneath southern Scandinavia and northern Germany: Precambrian crustal accretion in southern Baltica, Caledonian collision between Baltica and Avalonia along the Tornquist Suture Zone (TSZ), followed by Variscan collision and formation of the North German and the Norwegian-Danish basins, and more recent magmatic activity to the south. This study is particularly focused on the closure of the Tornquist Sea and the Caledonian collision between Baltica and Avalonia. A total of 29 stations, provided by GFZ and the University of Aarhus, were deployed between autumn 2010 and summer 2012, of which 25 form the main profile, and 4 are positioned in an off-line location. Waveform data are available from the GEOFON data centre, under network code ZW, and are available under CC-BY 4.0 license according to GIPP-rules.
We are providing the geophysical data used to develop a gravity validated 3D lithospheric configuration of the Caribbean and north South American plates. The sources of these data are described in Section 4 of this README. Republication of subsets of these data are with permission of the authors or allowed by the licences of the input data. This data repository contains the lithospheric layers of the gravity validated 3D structural and density model of the Caribbean and north South American plates. In this model, the integration of different publicly available geophysical datasets was made, after an interpolation to a homogeneous spatial resolution of 25 km was performed. The data repository also contains the average density of the crystalline crust obtained after forward modelling the gravity anomalies. Additionally, the rotation files of the GPlates reconstructions of the Caribbean Large Igneous Plateau (CLIP) back to 90 Ma are included. This kinematic analysis was based on different reconstructions previously published by other authors. Further information and citations are given on the README file associated to this data repository.
The scripts and workflow are supplementary material to "3D Modelling of Vertical Gravity Gradients and the delimitation of tectonic boundaries: The Caribbean oceanic domain as a case study" (Gómez-García et al., 2019).The codes include the calculation of the VGG response of a 3D lithospheric model, in spherical coordinates, using the software Tesseroids (Uieda, 2016). The "Readme_Workflow_2019_002.pdf" file provide very detail information about the structure of this repository, as well as the step-by-step for the scripts execution, and the list of the requiered software for the correct workflow performance.All the information provided here will allow the user to reproduce the results and figures of the main paper. Detailed information are also given in the associated README.
This dataset includes five stations of an Ocean Bottom Seismometer (OBS) experiment conducted at the southern end of the Fonualei Rift and Spreading Center in the Lau Basin, southwestern Pacific. The OBS recorded continuously for 32-days on 4 components, including a hydrophone and a 3-component 4.5 Hz geophone. The experiment was conducted during RV Sonne cruise SO267, project ARCHIMEDES I.
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