cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.5880/fidgeo.2021.026
title: Geochemical and strontium isotope data on Critical Zone compartments along a global soil erodosequence

description: We provide strontium isotope data (for both the "radiogenic" isotope ratio 87Sr/86Sr, and the "stable" isotope ratio 88Sr/86Sr, expressed as delta88Sr) for critical zone compartments (rock, saprolite, soil, plants, and river dissolved loads) at three sites along a global transect of mountain landscapes that differ in erosion rates – an “erodosequence”. These sites are the Swiss Central Alps, a rapidly-eroding post-glacial mountain belt; the Southern Sierra Nevada, USA, eroding at moderate rates; and the slowly-eroding tropical Highlands of Sri Lanka. Key metrics for strontium elemental partitioning (strontium concentrations and ratios to the major elements sodium and calcium) are also provided. All samples are assigned with International Geo Sample Numbers (IGSN), a globally unique and persistent Identifier for physical samples. The IGSNs are provided in the data tables and link to a comprehensive sample description. Further details on sampling and locations are provided in von Blanckenburg et al (2021). The IGSN data can be accessed by adding the IGSN after igsn.org, e.g. igsn.org/GFFB1005U
description: Strontium isotope analyses were obtained using multi-collector plasma-source mass spectrometry (MC-ICP-MS) after chromatographic extraction (Bouchez and bon Blanckenburg, Amer. J. Sci., 2021), and Sr concentrations, chemical depletion fraction (CDF) and Sr mass transfer coefficient (tSr) derive from X-ray fluorescence measurements on rock and regolith material (von Blanckenburg et al., 2021). 2SEt are the 95 % confidence intervals calculated as t·SD/√n, with SD = standard deviation of n replicate analyses, t = correction factor for low n from Student’s t-distribution at 95% probability. nm, ns, and nc refer to the number of runs of chromatographic separation, number of MC-ICP-MS sessions, and number of individual measurements that were performed for each solution. nm was used to calculated SEt For samples with nm=1, the uncertainty used in plots and calculations is equal to the 2SD measured for reference materials of a similar nature (SLRS-5 St-Lawrence River Water for water samples, SRM2709a San Joaquin Soil for saprolite and soil samples, BHVO-1 for rock samples, and SRM1515 Apple Leaves for plant samples).
description: The dataset consist of 8 Tables that are provided as Excel and printable PDF versions: Table A1. Swiss Alps analyses of soil, saprolite, rock Table A2. Swiss Alps analyses of water samples Table A3. Swiss Alps analyses of plant samples Table SN1. Sierra Nevada analyses of soil, saprolite, rock, bedload sediment and suspended stream load Table SN2. Sierra Nevada analyses of water samples Table SN3. Sierra Nevada analyses of plant samples Table SL1. Sri Lanka analyses of soil, saprolite, rock Table E. Relative elemental amounts (compared to bulk) present in the different extraction pools
DOI: 10.5880/gfz.3.3.2021.003
title: Geochemical data on silicon isotope and Ge/Si ratios along a global erodosequence

description: We provide geochemical data for three sites that define a gradient of erosion rates – an “erodosequence”. These sites are the Swiss Central Alps, a rapidly-eroding post-glacial mountain belt; the Southern Sierra Nevada, USA, eroding at moderate rates; and the slowly-eroding tropical Highlands of central Sri Lanka. Specifically, we provide silicon isotope ratios and germanium/silicon ratios and the major element composition of 1) rock, 2) saprolite, 3) soil, 4) plants, 5) river dissolved loads, 6) the soil and saprolite amorphous silica fraction (accessed with a NaOH leach), and 7) the soil and saprolite clay-size fraction (isolated with a differential settling protocol). These data serve two purposes. First, they allow us to improve understanding of the controls on silicon isotopes and germanium/silicon ratios in the 'Critical Zone'. Specifically, we can quantify the fractionation factors (for silicon isotopes) and the exchange coefficients (for germanium/silicon ratios), for secondary mineral precipitation and for biological uptake. Secondly, we can use mass-balance approaches to quantify the partitioning of silicon - a nutrient, and a major rock-forming element - among secondary minerals, plant material, and solutes. All samples are assigned with International Geo Sample Numbers (IGSN), a globally unique and persistent Identifier for physical samples. The IGSNs are provided in the data tables and link to a comprehensive sample description.
description: This dataset consists of five tables: S1. Analyses of soil, saprolite, and rock from the Swiss Alps study site S2. Analyses of soil, saprolite, and rock from the Sierra Nevada study site S3. Analyses of soil, saprolite, and rock from the Sri Lanka study site S4. Analyses of stream water from the Swiss Alps, Sierra Nevada, and Sri Lanka study sites S5. Analyses of plant material from the Swiss Alps, Sierra Nevada, and Sri Lanka study sites
DOI: 10.5880/gfz.4.6.2020.001
title: CO2 efflux, soil temperature and carbon/helium isotope results from the Los Humeros geothermal field, Mexico

description: Magmatic volatiles can be considered as the surface fingerprint of active volcanic systems, both during periods of quiescent and eruptive volcanic activity. The spatial variability of gas emissions at Earth’s surface is a proxy for structural discontinuities in the subsurface of volcanic systems. We conducted extensive and regular spaced soil gas surveys within the Los Humeros geothermal field to improve the understanding of the structural control on fluid flow. Surveys at different scales were performed with the aim to identify areas of increased gas emissions on reservoir scale, their relation to unknown/knows volcano-tectonic structures on fault scale favoring fluid flow, and determine the origin of gas emissions. Herein, we show results from a carbon dioxide efflux scouting survey, which was performed across the main geothermal production zone together with soil temperature measurements. We identified five areas with increased carbon dioxide emissions, where further sampling was performed with denser sampling grids to understand the fault zone architecture and local variations in gas emissions. We show that a systematic sampling approach on reservoir scale is necessary for the identification and assessment of major permeable fault segments. The combined processing of CO2 efflux and carbon/helium isotopes facilitated the detection of permeable structural segments with a connection to the deep, high-temperature geothermal reservoir, also in areas with low to intermediate carbon dioxide emissions. The results of this study complement existing geophysical datasets and define further promising areas for future exploration activities in the north- and southwestern sector of the production field. The data are presented as one zip folder with 4 data tables (tab delimited text format) according to the measurement variable. The columns are defined in each data file.
DOI: 10.5880/gfz.4.8.2021.003
title: Continuous monitoring of soil CO2 efflux and atmospheric parameters at the Los Humeros Volcanic Complex

description: Carbon dioxide is the most abundant, non-condensable gas in volcanic systems, released into the atmosphere through either diffuse or advective fluid flow. The emission of substantial amounts of CO2 at Earth’s surface is not only controlled by volcanic plumes during periods of eruptive activity or fumaroles, but also by soil degassing along permeable structures in the subsurface. Monitoring of these processes is of utmost importance for volcanic hazard analyses, and is also relevant for managing geothermal resources. Fluid-bearing faults are key elements of economic value for geothermal power generation. Here, we describe for the first time how sensitively and quickly natural gas emissions react to changes within a deep hydrothermal system due to geothermal fluid reinjection. For this purpose, we deployed an automated, multi-chamber CO2 flux monitoring system within the damage zone of a deep-rooted major normal fault in the Los Humeros Volcanic Complex (LHVC) in Mexico and recorded data over a period of five months. After removing the atmospheric effects on variations in CO2 flux, we calculated correlation coefficients between residual CO2 emissions and reinjection rates, identifying an inverse correlation of ρ = -0.51 to -0.66. Our results indicate that gas emissions respond to changes in reinjection rates within 24 hours, proving an active hydraulic communication between the hydrothermal system and Earth’s surface. This finding is a promising indication not only for geothermal reservoir monitoring but also for advanced long-term volcanic risk analysis. Response times allow for estimation of fluid migration velocities, which is a key constraint for conceptual and numerical modelling of fluid flow in fracture-dominated systems.
DOI: 10.5880/fidgeo.2021.030
title: Stable isotope (2H and 18O) depth profiles of pore waters and inferred soil physical parameters in the Attert catchment, Luxembourg

description: Depth profiles of stable water isotopes in the soil provide important information on flow and transport processes in the subsurface. We sampled depth profiles of stable water isotopes (2H and 18O) in the pore waters on two occasions at 46 sites in the Attert catchment, Luxembourg and are partly located in mixed deciduous forest and partly on grassland. These sites correspond to the sensor cluster sites of the DFG research unit CAOS. Sampling took place once between February 2012 and October 2013 and once in June 2014. Sampling procedure: We took 1-3 soil cores of 8 cm diameter in close proximity with a percussion drill (Atlas Copco Cobra, Stockholm, Sweden) at each study site within a radius of 5 m from the soil moisture sensor profiles. We drilled as deep as possible and divided the extracted soil cores into subsamples of 5 to 10 cm length and sealed the material in air tight bags (Weber Packaging, Güglingen, Germany). The soil sample depths were corrected for compaction during the drilling pro-cess and are provided as the mean depth of 5 or 10 cm soil core subsamples. For isotope analyses of the pore water, we used the direct equilibration method (Wassenaar et al., 2008). Analyses were carried out at the Chair of Hydrology, University of Freiburg. We provide detailed information about the laboratory analyses in Sprenger et al. (2015) and Sprenger et al. (2016) and the data description associated with the data.
DOI: 10.5880/gfz.1.1.2021.002
title: GNSS signal power data for reflectometry recorded during the MOSAiC Expedition (leg 1)

description: Reflected signals of Global Navigation Satellite Systems (GNSS) have been investigated for various applications in remote sensing over the last three decades. The overall research field of GNSS reflectometry includes the retrieval of sea ice parameters as an important application. For this purpose, GNSS reflectometry data have been recorded over the Arctic Ocean with a dedicated receiver setup during the MOSAiC expedition (Multidisciplinary drifting Observatory for the Study of Arctic Climate). The setup was mounted on the German research icebreaker Polarstern (AWI, 2017) that drifted during nine months of the expedition with the Arctic sea ice. The here described data set comprises the expedition’s first leg in autumn 2019. It includes the drift period of the ship from 27th September until 14th December at about 82°N to 87°N in the Siberian Sector of the Arctic. The data set is based on essential contributions of setup & data recording (by GFZ), maintenance & data transfer (by AWI and MOSAiC partners), processing to data level 1 & documentation (by DLR-SO). The level 1 data consist of GNSS signal power estimates of the direct and reflected signal. Data appear in event files (netcdf format) sorted into day folders. Each event includes observations of a satellite on a continuous track, here, in a satellite elevation range from min. 1° to max. 45°. A dedicated GNSS reflectometry receiver, of GORS (GNSS Occultation Reflectometry Scatterometry) type, was used for the measurements. It is equipped with four antenna front-ends. A master channel and two slave channels are assigned to the front-ends. The master channel tracks the GNSS signal on the direct link. The slave channels are dedicated for observations of reflection events: one at left-handed (LH) and another one at right-handed (RH) circular polarization. The respective up-looking master antenna and port-side looking slave antenna (dual-polarization) are set up with a short baseline on the ship’s observation deck, about 22 m above the water level. The given ship-based geometry results in events with rather short excess paths of the reflected signal relative to the direct signal, much less than the range of a code chip (about 300 m for GPS L1 C/A). Interferometric pattern of direct and reflected signal contributions are observed in the channel. A separation step is required in further processing.
DOI: 10.5880/fidgeo.2021.002
title: Analysis of Strong Motion Waveforms Near the Locations of Detections by the Earthquake Network App in Chile, the USA and Italy

description: The 'Earthquake Network’ (EQN) is an app which detects earthquakes by creating an ad-hoc network of smartphones' accelerometer sensors and provides early warnings for earthquakes via the same smartphone app. Detections are not due to individual smartphone measurements but due to near-simultaneous trigger signals from clusters of smartphones running the app. Therefore detections are normally located in the closest populated regions to an earthquake's epicentre. In order to investigate the mechanisms of EQN's earthquake detection system, we searched for seismic accelerometer stations with publically available data that were close to the EQN detection locations (rather than close to the epicentre). This confirmed that EQN's detections followed strong shaking motions but that detections could follow both P-phase or S-phase rather than consistantly being sensitive to only one particular phase. It also showed that detections generally occurred between 0 - 5 seconds after the peak ground acceleration measured by the seismic station. Analysis was conducted on 550 detections made by the EQN system between 2017-12-15 and 2020-01-31 in Chile, Italy and the USA. Strong motion accelerometer data was collected from seismic stations via the FDSN protocol. The data was calibrated, detrended and a small time shift was applied to correct for differences in distances from the epicentre between the EQN detection and the strong motion seismic station. Calibrated waveform data was obtained for 410 EQN detections. Plots were made for each event and an analysis was carried out on the dataset to compare EQN detection times with the peak ground acceleration measured by the nearest seismic station. The dataset consists of a zip-file containing a table of results and some summary graphs derived from it as well as a set of 410 graphs of strong motion files that are presented as image files (png-files). The graphs show the waveform data for a seismic station within 20 km of each EQN detection.
description: Ground motion data was retrieved from seismic networks via the FDSN protocol via the IRIS and ORFEUS institutes. This data was calibrated using station inventory files also downloaded via FDSN and filtered between 0.5 - 12 Hz. A small time shift was applied to correct for differences in distances from the epicentre between the EQN detection and the strong motion seismic station. This time shift assumed a seismc phase velocity of 8.04km/s.
DOI: 10.5880/fidgeo.2021.001
title: A Questionnaire Survey of the Earthquake Network App's Users in Peru Following an M8 Earthquake in 2019.

description: The 'Earthquake Network’ (EQN) is an app which detects earthquakes by creating an ad-hoc network of smartphone's accelerometer sensors and provides early warnings of earthquakes via the same smartphone app. The EMSC (Euro-Mediterranean Seismological Centre) and the University of Bergamo conducted an online survey, following an earthquake of magnitude M8 on 2019-05-26 07:41:13.6 UTC in Northern Peru with epicentre (5.81S, 75.27W). This survey targeted EQN users in the felt area of the earthquakes and was conducted from 2019-07-23 to 2019-08-18. It aimed at assessing users’ understanding and reaction to the EQN early warning for this specific earthquake. The questionnaire was written in Spanish since it is the most commonly spoken language in the studied area. Individuals who use the app in Spanish were invited to complete the survey via an advertisement on the Earthquake Network app. A PDF containing the questionnaire and the relationship between the questions is included in this archive. 3805 respondents took the survey, including 2 719 that were actually in the area at the time. The analysis Results derived from this dataset will be included as part of a submitted Science article (Bossu et al. '“Shaking in 5 seconds!” A Voluntary Smartphone-based Earthquake Early Warning System', 2021) to show that respondents received notifications from the Earthquake Network App before feeling the shaking but also that many did not immediately “drop, hold and cover' and were too intent on warning those close to them of the impending danger. All respondents consented that their data could be used for research purposes. The EMSC and University of Bergamo made sure not to collect or diffuse personal data. The dataset is a zip-file that contains the questionnaire responses as a comma-separated text file (csv) and a pdf containing a representation of the questionnaire that was presented to respondents.
DOI: 10.5880/isg.2019.005
title: The GEOF-NTIS quasi-geoid based on Least Squares modification of Stokes integral with additive corrections for the Colorado Experiment: ColLSMSA-GEOF2019

description: The ColLSMSA-GEOF2019 gravimetric quasi-geoid model has been computed by the Faculty of Geodesy, University of Zagreb (GEOF) in cooperation with the New technologies for the Information Society, University of West Bohemia (NTIS). It has been worked out in the frame of the International Association of Geodesy Joint Working Group 2.2.2 "The 1 cm geoid experiment" and the so called "Colorado experiment". The area covered by the model is 251°E ≤ longitude ≤ 257°E, 36°N ≤ latitude ≤ 39°N with a grid spacing of 1' in both latitude and in longitude. The geoid is computed using a two-step procedure. First, the terrestrial and airborne gravity data are gridded by Least Squares Collocation (LSC) with a planar logarithmic covariance model in the framework of a remove-compute-restore procedure. Long wavelengths are modelled by XGM2016 up to degree and order 500, while short wavelengths are taken from the topographic gravity effect. In the second step, the resulting 1'x1' grid of Molodensky-type free-air gravity anomalies is used to compute geoidal heights by using Least Squares Modification of Stokes’ formula with Additive corrections (LSMSA). In particular, the geoidal heights are obtained by using a biased modification of the Stokes kernel (0.5° spherical cap size integration) and then by adding four corrections, namely topographic, downward continuation, atmospheric and ellipsoidal corrections. Finally, the conversion from geoid to quasi-geoid is computed only approximately using the formula by Heiskanen and Moritz (1967). The accuracy of the quasi-geoid model, when compared against GSVS17 GPS/leveling, is equal to 3.6 cm. The quasi-geoid model is provided in ISG format 2.0 (ISG Format Specifications), while the file in its original data format is available at the model ISG webpage.
description: The International Service for the Geoid (ISG) was founded in 1992 (as International Geoid Service - IGeS) and it is now an official service of the International Association of Geodesy (IAG), under the umbrella of the International Gravity Field Service (IGFS). The main activities of ISG consist in collecting, analysing and redistributing local and regional geoid models, as well as organizing international schools on the geoid determination (Reguzzoni et al., 2021).
DOI: 10.5880/gfz.1.4.2021.001
title: Hyperspectral imaging data of the northern mine face and of laboratory samples of the copper-gold-pyrite mine Apliki, Nicosia District, Republic of Cyprus

description: The data set contains VNIR and SWIR raw and reference hyperspectral imaging data of the Apliki mine open cut and of samples from the surface of the mine measured in the laboratory. It is con-nected to the published spectral library and chemical analyses of 37 different surface materials from the copper-gold-pyrite mine Apliki in the Republic of Cyprus (Koerting et al., 2019). The field outcrop scan was acquired in March 2018 in cooperation with the Geological Survey Department of the Republic of Cyprus (GSD) and the German Research Centre for Geosciences (GFZ). The laboratory sample scan presented in this document is a collection of hyperspectral scans compiled in one large dataset. The hyperspectral data in the field and the lab were acquired with the HySpex sys-tem in a range of 414 – 2498 nm. The field data is shared as one VNIR and one SWIR radiance and reflectance data cube each. The laboratory data is shared as one full VNIR-SWIR (414 – 2450nm) reflectance data cube that was processed and corrected for the detector jump, data spikes and the last 8 SWIR bands were clipped due to a low signal to noise ratio (SNR). The data and the samples originate from fieldwork in the Republic of Cyprus and laboratory work at the GFZ Potsdam. A detailed description of the data acquisition and processing can be found in Koerting (2021).
DOI: 10.5880/isg.2019.006
title: The GEOF-NTIS geoid based on Least Squares modification of Stokes integral with additive corrections for the Colorado Experiment: ColLSMSA-GEOF2019

description: The ColLSMSA-GEOF2019 gravimetric geoid model has been computed by the Faculty of Geodesy, University of Zagreb (GEOF) in cooperation with the New technologies for the Information Society, University of West Bohemia (NTIS). It has been worked out in the frame of the International Association of Geodesy Joint Working Group 2.2.2 "The 1 cm geoid experiment" and the so called "Colorado experiment". The area covered by the model is 251°E ≤ longitude ≤ 257°E, 36°N ≤ latitude ≤ 39°N with a grid spacing of 1' in both latitude and in longitude. The geoid is computed using a two-step procedure. First, the terrestrial and airborne gravity data are gridded by Least Squares Collocation (LSC) with a planar logarithmic covariance model in the framework of a remove-compute-restore procedure. Long wavelengths are modelled by XGM2016 up to degree and order 500, while short wavelengths are taken from the topographic gravity effect. In the second step, the resulting 1'x1' grid of Molodensky-type free-air gravity anomalies is used to compute geoidal heights by using Least Squares Modification of Stokes’ formula with Additive corrections (LSMSA). In particular, the geoidal heights are obtained by using a biased modification of the Stokes kernel (0.5° spherical cap size integration) and then by adding four corrections, namely topographic, downward continuation, atmospheric and ellipsoidal corrections. The accuracy of the geoid model, when compared against GSVS17 GPS/leveling, is equal to 3.9 cm. The geoid model is provided in ISG format 2.0 (ISG Format Specifications), while the file in its original data format is available at the model ISG webpage.
description: The International Service for the Geoid (ISG) was founded in 1992 (as International Geoid Service - IGeS) and it is now an official service of the International Association of Geodesy (IAG), under the umbrella of the International Gravity Field Service (IGFS). The main activities of ISG consist in collecting, analysing and redistributing local and regional geoid models, as well as organizing international schools on the geoid determination (Reguzzoni et al., 2021).