ALBERT

Description: Abstract

Description: River water and suspended sediment samples were collected between 2015 and 2018 from the Narayani, Saptakoshi and Sunkoshi rivers in Nepal. Samples formed part of the Perturbations of Earth Surface Processes by Large Earthquakes PRESSurE Project (https://www.gfz-potsdam.de/en/section/geomorphology/projects/pressure/). This project aims to better understand the role of earthquakes on earth surface processes. Hydrological stations were installed on the rivers draining the epicentral area following the April 2015 Gorkha earthquake (Mw 7.9). The stations were operated for four consecutive monsoon seasons. All stations were equipped with river stage height measurements and manned daily for sampling. A small batch of river water samples were also collected from the Narayani River. These samples were collected upstream of Narayanghat using a raft between 2015 and 2017. These samples were collected at varying depths in the river. Dissolved river water ion concentrations (N=672) and sediment-adsorbed cation concentrations (N=74) were determined. Radiogenic strontium isotopes (87Sr/86Sr) of both phases were measured for a small number of paired samples (N=9). Dissolved river water anion concentrations were measured at the GFZ German Research Centre for Geosciences, Potsdam, Germany. Dissolved river water cation concentrations were measured at GFZ German Research Centre for Geosciences, Potsdam, Germany and the Department of Earth Sciences, University of Cambridge, Cambridge, UK. Sediment-adsorbed cation concentrations and radiogenic strontium isotope ratios were measured at the Department of Earth Sciences, University of Cambridge, Cambridge, UK.

Description: Other

Description: This data set forms part of the Perturbations of Earth Surface Processes by Large Earthquakes PRESSurE Project (https://www.gfz-potsdam.de/en/section/geomorphology/projects/pressure/). Strong earthquakes cause transient perturbations to the near Earth’s surface system. These include widespread land-sliding, subsequent mass movement, and the loading of rivers with sediments. In addition, brittle-rock deformation occurs during the event, forming cracks that affect rock strength and hydrological conductivity. Often overlooked in the immediate aftermath of an earthquake, these perturbations can represent a major part of the overall disaster with impacts that can persist for years before restoring to background conditions. This relaxation phase is therefore part of seismically induced earthquake changes and needs to be monitored to understand the full impact on the Earth system. The fundamental questions motivating the PRESSurE project are ‘How do earthquakes impact erosion during and following seismic activity?’ and ‘What is the role of earthquakes on Himalayan landscape evolution?’. In early June, shortly after the April 2015 Gorkha earthquake, we installed twelve hydrological stations covering all rivers draining the epicentral area. Each station was equipped for daily river water and suspended sediment sampling. Samples are filtered and packed in Nepal, before being shipped to the sediment lab at GFZ for further analysis (SedLab: https://labinfrastructure.geo-x.net/laboratories/91). The sampling network is complemented by an array of seismometers, repeated satellite image observations, and on-side stage high recording. This array is optimized for the monitoring of Earth surface processes (land-sliding, mass wasting and debris flows) and for the monitoring of properties of the shallow subsurface by coda analysis. The monitoring network is the first and most complete observatory to monitor the perturbation of Earth surface process by a major earthquake.

Description: Abstract

Description: The dataset contains three seismicity catalogs covering the first 5 days of the aftershock sequence of the Mw 7.8 Karamanmaraş and Mw 7.6 Elbistan earthquakes that occurred in Türkiye on February 6th, 2023. The catalogs are derived from machine learning (ML) approaches operating on continuous data from 38 permanent seismological stations covering the area of the aftershock sequence and span the time interval 06.02.2023-10.02.2023. The seismological stations are operated by AFAD (Disaster and Emergency Management Presidency of Turkey) and KOERI (Kandilli Observatory and Earthquake Research Institute). Automatic P- and S-phase picks were obtained using the deep learning PhaseNet software (Zhu & Beroza, 2019), and either GaMMA (Zhu et al., 2022) or GENIE (McBrearty & Beroza, 2023) routines were used to associate these phases into seismic events. The probabilitic NLLoc earthquake location software (Lomax et al., 2009) was used to produce single event locations and final relative relocations were obtained after applying the hypoDD software (Waldhauser & Ellsworth, 2000). This resulted in two single event location NLLoc aftershock catalogs based on GaMMA and GENIE event association and containing 17,550 and 14,805 event detections in the time interval 06.02.2023 01:18 UTC - 11.02.2023 00:00 UTC, respectively. The hypoDD based catalog of better constrained relative relocations contains 5,215 events. The magnitude range is between M-0.1 and M6.9 with time-variable magnitude of completeness. The catalog covers the area 36.00S-39.00S and 35.40E-40.00E. The full description of the data and methods is provided in the data description file.

Description: During expedition EMB201 in the Baltic Sea we investigated the local producers of glycerol dialkyl glycerol tetraethers (GDGT) and their thriving depth by a combined 16S rRNA gene amplicon sequencing/ CARD-FISH and lipidomic approach. Water samples were taken in December 2018 by a pump-CTD, a giant water sampler and with Niskin bottles at the surface, suboxic and sulfidic zones of the Landsort Deep, Fårö Basin and East Gotland Basin. This data set contains the CARD-FISH and lipidomics data, while the 16S rRNA gene sequencing data is available on ENA. Cell abundance was analysed in an aliquot of 40 ml filtered (pore size 0.22 micro m) sea water fixed with particle-free formaldehyde. Archaeal cells on the filters were specifically hybridized via catalysed reporter deposition-fluorescence in situ hybridization (CARD-FISH) using the Cren537 probe. Cells on the hybridized filter were counter-stained with 40,6-diamidin-2-phenylindol (DAPI). For lipid analysis, 150–600 L sea water were filtered with a flow rate of 1.5 L min-1 on pre-ashed, 142-mm-diameter, 0.7µm pore size glass fibre GF/F filters, and frozen at –20 °C. The filters were lyophilized before different extraction methods were used to obtain intact and core GDGTs by ultra-sonification in different solvent mixtures. The combined supernatants were phase separated before analysis by high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS2) for intact polar lipids and by high performance liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry (HPLC APCI-MS; ThermoScientific) for core GDGTs.

Description: The dataset contains ocean bottom hydrophone (OBH) data acquired along profile P05 during RV Sonne Expedition SO267 (project ARCHIMEDES) to the Lau Basin, Southwestern Pacific in December 2018. This seismic refraction data set contains 34 OBS that all recorded the shots along the ~220 km long seismic transect successfully. Data for two different shot intervals (50m and 150m) were acquired shooting from east to west and from west to east respectively. An 84 l airgun array served as seismic source that was towed behind the vessel 8 m below sea surface. The data were processed using standard methods for relocation of the instrument at the seafloor, clock drift correction, deconvolution and filtering.

Description: The ²³⁴Th-²³⁸U radioactive pair has been extensively used to evaluate the efficiency with which photosyntetically fixed carbon is exported from the surface ocean by means of the biological pump since the 90's. The seminal work of Buesseler et al. (1992) proposed that particulate organic carbon (POC) flux can be indirectly calculated from ²³⁴Th distributions if the ratio of POC to ²³⁴Th measured on sinking particles (POC:²³⁴Th) at the desired export depth is known. Since then, a huge amount of ²³⁴Th depth profiles have been collected using a variety of sampling instruments and strategies that have changed along years. This is a global oceanic compilation of ²³⁴Th measurements, that collects results from innumerable researchers and laboratories over a period exceeding 50 years. The present compilation is made of a total 223 datasets: 214 from studies published either in articles in referred journals, PhD thesis or repositories, and 9 unpublished datasets. Including measurements from JGOFS, VERTIGO and GEOTRACES programs, with sampling from approximately 5000 locations spanning all the oceans. The compilation includes total ²³⁴Th profiles, dissolved and particulate ²³⁴Th concentrations, and POC:²³⁴Th ratios (both from pumps and sediment traps) for two sizes classes (1-53 μm and 〈 53 μm) when available. Appropriate metadata have been included, including geographic location, date, and sample depth, among others. When available, we also include water temperature, salinity, ²³⁸U data and particulate organic nitrogen data. Data sources and methods information (including ²³⁸U and ²³⁴Th) are also detailed along with valuable information for future data analysis such as bloom stage and steady/non-steady state conditions at the sampling moment. This undertaking is a treasure of data to understand and quantify how oceanic carbon cycle functions and how it will change in future. The compilation can be downloaded in three different ways: 1) A single merged file including all the individual excel files. This option can be accessed under "Other version: More than 50 years of Th-234 data: a comprehensive global oceanic compilation (single xlsx file)". 2) A summary table that includes details from cruise, sampling dates, techniques applied, authors and DOI of the compiled ²³⁴Th data, among others, each line corresponds to a specific dataset. The table can be accessed by clicking ""View dataset as HTML" and downloaded in "Download dataset as tab-delimited text". 3) Individual Excel files for each dataset can be manually chosen from the summary table, corresponding to the complete ²³⁴Th dataset and metadata from a specific publication or program. This option is available by clicking "View dataset as HTML". Furthermore, all files referred to can be downloaded in one go as ZIP or TAR.