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Higher frequency data products of the International Monitoring System’s infrasound stations

This dataset consists of data products derived from broadband signal detection lists that have been processed for the certified infrasound stations of the International Monitoring System. More specifically, within the CTBT-relevant infrasound range (around 0.01-4 Hz), this dataset covers higher frequencies (1-3 Hz) and is therefore called the ‘hf’ product. The temporal resolution (time step and window length) is 5 min. For processing the infrasound data, the Progressive Multi-Channel Correlation (PMCC) array processing algorithm with a one-third octave frequency band configuration between 0.01 and 4 Hz has been used. The detected signals from the most dominant directions in terms of number of arrivals within a time window and the product-specific frequency range are summarized at predefined time steps. Along with several detection parameters such as the back azimuth, apparent velocity, or mean frequency, additional quantities for assessing the relative quality of the detection parameters are provided. The dataset is available as a compressed .zip file containing the yearly data products (.nc files, NetCDF format) of all certified stations (since 2003). Further information on the processing and details about the open-access data products can be found in: Hupe et al. (2022), IMS infrasound data products for atmospheric studies and civilian applications, Earth System Science Data, doi:10.5194/essd-14-4201-2022

Very low frequency data products of the International Monitoring System’s infrasound stations

This dataset consists of data products derived from broadband signal detection lists that have been processed for the certified infrasound stations of the International Monitoring System. More specifically, this dataset, called the ‘maw’ product, covers a very low frequency range of infrasound (0.02-0.07 Hz). The temporal resolution (time step and window length) is 30 min. For processing the infrasound data, the Progressive Multi-Channel Correlation (PMCC) array processing algorithm with a one-third octave frequency band configuration between 0.01 and 4 Hz has been used. The detected signals from the most dominant directions in terms of number of arrivals within a time window and the product-specific frequency range are summarized at predefined time steps. Along with several detection parameters such as the back azimuth, apparent velocity, or mean frequency, additional quantities for assessing the relative quality of the detection parameters are provided. The dataset is available as a compressed .zip file containing the yearly data products (.nc files, NetCDF format) of all certified stations (since 2003). Further information on the processing and details about the open-access data products can be found in: Hupe et al. (2022), IMS infrasound data products for atmospheric studies and civilian applications, Earth System Science Data, doi:10.5194/essd-14-4201-2022.

Microbarom low-frequency data products of the International Monitoring System’s infrasound stations

This dataset consists of data products derived from broadband signal detection lists that have been processed for the certified infrasound stations of the International Monitoring System. More specifically, this dataset covers the dominant frequency range of microbaroms (0.15-0.35 Hz) and is therefore called the ‘mb_lf’ product. The temporal resolution (time step and window length) is 15 min. For processing the infrasound data, the Progressive Multi-Channel Correlation (PMCC) array processing algorithm with a one-third octave frequency band configuration between 0.01 and 4 Hz has been used. The detected signals from the most dominant directions in terms of number of arrivals within a time window and the product-specific frequency range are summarized at predefined time steps. Along with several detection parameters such as the back azimuth, apparent velocity, or mean frequency, additional quantities for assessing the relative quality of the detection parameters are provided. The dataset is available as a compressed .zip file containing the yearly data products (.nc files, NetCDF format) of all certified stations (since 2003). Further information on the processing and details about the open-access data products can be found in: Hupe et al. (2022), IMS infrasound data products for atmospheric studies and civilian applications, Earth System Science Data, doi:10.5194/essd-14-4201-2022

Microbarom high-frequency data products of the International Monitoring System’s infrasound stations

This dataset consists of data products derived from broadband signal detection lists that have been processed for the certified infrasound stations of the International Monitoring System. More specifically, this dataset covers, among other phenomena, the upper frequency range of microbaroms (0.45-0.65 Hz) and is therefore called the ‘mb_hf’ product. The temporal resolution (time step and window length) is 15 min. For processing the infrasound data, the Progressive Multi-Channel Correlation (PMCC) array processing algorithm with a one-third octave frequency band configuration between 0.01 and 4 Hz has been used. The detected signals from the most dominant directions in terms of number of arrivals within a time window and the product-specific frequency range are summarized at predefined time steps. Along with several detection parameters such as the back azimuth, apparent velocity, or mean frequency, additional quantities for assessing the relative quality of the detection parameters are provided. The dataset is available as a compressed .zip file containing the yearly data products (.nc files, NetCDF format) of all certified stations (since 2003). Further information on the processing and details about the open-access data products can be found in: Hupe et al. (2022), IMS infrasound data products for atmospheric studies and civilian applications, Earth System Science Data, doi:10.5194/essd-14-4201-2022

Infrasound records of Stromboli eruptions on July 3 and August 28 2019

Two strong eruptions of Stromboli Volcano (38.789°N 15.213°E, 920 m) occurred on July 3rd and August 28th 2019. This data set provides the infrasound records in terms of raw pressure data in Pascal of both eruptions available at BGR’s infrasound array I26DE in Germany as well as infrasound arrays OHP and CEA in France. The publication “Using dense seismo-acoustic network to provide timely warning of the 2019 paroxysmal Stromboli eruptions” (Le Pichon et al., 2021, Scientific Reports) provides further details on this data set and its scientific application. Data format: The data are provided as ASCII files (separate file for each infrasound sensor and hour of measurement, plus a README file).

Die Bedeutung volatiler Arsen-Emissionen aus vulkanischen Gebieten

Arsen ist durch sein ubiquitäres Vorkommen eines der bestuntersuchten Elemente in Gestein, Boden und Wasser. Über Arsen in der Atmosphäre ist dagegen wenig bekannt. Die größten Freisetzungen stammen aus Punktquellen, wobei vulkanische Gebiete die wichtigsten natürlichen Quellen sind. Meist wird angenommen, dass die atmosphärische Ausbreitung von partikulärem Arsen abhängt, während volatile Arsenspezies ignoriert wurden trotz hoher Toxizität schon bei geringen Konzentrationen. Sie wurden als exotisch und zu kurzlebig, um umweltrelevant zu sein, eingestuft. Neuere Untersuchungen zeigen aber, dass die Stabilität volatilen Arsens bislang unterschätzt wurde. Ein Mangel an Probenahme-, Stabilisierungs- und Analysetechniken verhinderte auch, dass speziesselektive Massenbilanzen für atmosphärisches Arsen aufgestellt und abiotische von biotischen Bildungsmechanismen unterschieden werden konnten. Die Hypothese des vorliegenden Antrags ist, dass volatile Arsenspezies mehr zum globalen biogeochemischen Kreislauf beitragen und über größere Distanzen transportiert werden als bisher angenommen. Desweiteren wird postuliert, dass neben primärer abiotischer Freisetzung mikrobielle Gemeinschaften sekundär Arsen volatilisieren und die Speziierung bestimmen. Ein erstes Ziel ist die Entwicklung einer neuen, feldtauglichen Methode zur Beprobung volatiler Arsenspezies. Dafür werden Extraktionsfallen aus Stahlnadeln gefüllt mit Polymersorbenten verwendet (Needle Trap Devices, NTDs). NTDs werden durch aktives Pumpen beladen, was die Quantifizierung der Flussrate und Berechnung absoluter Konzentrationen ermöglicht. NTDs werden in der organischen Chemie routinemäßig eingesetzt. Ihr Potential, volatiles Arsen quantitativ und spezieserhaltend zu sorbieren, ist unbekannt. Sorptionsmaterial, Pumpraten, Lagerbedingungen müssen optimiert und Konkurrenzsorption anderer volatiler Metall(oid)e oder vulkanischer Gase (H2O, SO2, H2S) eliminiert werden. Zur Analyse wird eine moderne Kopplungstechnik verwendet (GC-MS split ICP-MS): Nach gaschromatographischer Trennung wird der Probenfluss gesplittet; ein Massenspektrometer ermöglicht die molekulare Identifikation unbekannter Spezies, ein induktiv-gekoppeltes Plasma-MS die Element-Quantifizierung. Das zweite Ziel ist die Erfassung der Bedeutung volatiler Arsenfreisetzung und -verteilung in drei Gebieten unterschiedlicher vulkanischer Aktivität (Mt.Etna - Vulcano - Yellowstone National Park). Messungen entlang von Transekten sollen die Veränderung der volatilen Arsenmenge und -speziierung während des Transports aufzeigen. On-site Inkubationstests mit extremophilen Bakterien sollen zeigen, ob es zu mikrobieller Volatilisierung methylierter Arsenate und Methylierung von Arsin in der Gasphase kommt. Gesamtziel ist, durch das Bereitstellen einer Methode und den Nachweis der Rolle von volatilem Arsen exemplarisch in vulkanischen Gebieten eine neue Bewertung der Bedeutung volatiler Metall(oid)e für globale Stoffkreisläufe anzustoßen

Mechanical test data of quartz sand, garnet sand, gypsum powder (plaster), kaolin and sand-plaster mixtures used as granular analogue materials in geoscience laboratory experiments

This dataset provides mechanical test data for quartz sand (“MAM1ST-300”, Sibelco, Mol, Belgium), gypsum powder (plaster; “Goldband”, Knauf), kaolin clay powder, garnet sand, and mixtures of quartz sand and gypsum powder, used at the Analogue Laboratory of the Department of Geography at the Vrije Universiteit Brussel, Brussels, Belgium, for simulating brittle rocks in the upper crust (Poppe et al., 2019). The measured properties are density ρ, tensile strength T0, shear strength σ, obtained by density measurements, ring-shear tests (RST; at Helmholtz Centre Potsdam GFZ, Germany), direct shear tests, traction tests (at University of Maine, Le Mans, France) and extension tests. The obtained tensile strengths and shear strengths reconstruct two-dimensional failure envelopes for each material. By fitting linear Coulomb and non-linear combined Griffith failure criteria to the characterised failure envelopes (Jaeger et al., 2007), the internal friction coefficient µC, Coulomb cohesion CC and Griffith cohesion CG are obtained. The influence of the material emplacement technique has been investigated in Poppe et al. (2021) to which this data set is supplementary, by repeat characterisation of the above physical parameters under three emplacement conditions, i.e. sieving, pouring (non-dried state) and compaction after pouring (oven-dried state). We find that densities of the materials and mixtures range from ~1600 kg.m³ (sieved) and ~1700 kg.m³ (compacted) for pure quartz sand to ~600 kg.m³ (poured) to ~900 kg.m³ (compacted) for pure plaster. Tensile strengths range from ~166 Pa (sand) to ~425 Pa (plaster). Velocity ring-shear tests on a 90 wt% quartz sand – 10 wt% plaster mixture show a minor shear rate-weakening of <2% per ten-fold increase in shear velocity. The materials show a behavior ranging from Mohr-Coulomb behavior for the materials with coarser grain size (sands) to combined Griffith-Mohr-Coulomb behavior for the powder materials (plaster, kaolin), with the sand-plaster mixtures occupying a spectrum between both end-members. Peak friction coefficients range from ~0.5 (sand) to ~0.6 (plaster) with a maximum of ~0.9 (80:20 wt% sand:plaster), peak Coulomb cohesions range from 13 Pa (sand) to 248 Pa (plaster), peak Griffith cohesions range from ~10 Pa (sand) to ~425 Pa (plaster).

Seismological experiment at Strokkur from 2020

Seismological experiment at Strokkur from 2020" is a seismological experiment realized at the most active geyser on Iceland by Eva Eibl (University of Potsdam) in collaboration with Gylfi P. Hersir formerly at ISOR Iceland. The geyser is part of the Haukadalur geothermal area in south Iceland, which contains numerous geothermal anomalies, hot springs, and basins (Walter et al., 2018). Strokkur is a pool geyser and has a silica sinter edifice with a water basin on top, which is about 12m in diameter with a central tube of more than 20m depth. The aim of the seismic experiment is to monitor eruptions of Strokkur geyser from March 2020 using three broadband seismic stations (Nanometrics Trillium Compact 120s). Sensors were buried at distances of 38.8m (GE4, SE), 47.3m (GE3, SW), and 42.5m (GE2, N) from Strokkur center. Within this time period about 1 month of data is missing due to power outages. At any other times at least one station recorded the eruptions. From this dataset, converted to MSEED using Pyrocko, currently a catalogue of 506,131 water fountains was determined and further investigated in Eibl et al. (2025). In addition, Eibl et al. (2025) assessed the effect of the weather on the system including the bubble trap suspected at around 24 m depth by Eibl et al. (2021). Waveform data are available from the GEOFON data centre, under network code 2Z.

Seismic array data for monitoring and tracking tremor sources during subglacial floods and volcanic eruptions at Vatnajökull (Vatna Glacier), Iceland

As part of project FUTUREVOLC, European volcanological supersite in Iceland: a monitoring system and network for the future, two 7-element seismic broadband arrays were installed outside the western margin of Vatnajökull glacier, Iceland. The goal was to study seismic tremor associated with floods originating in the eastern and western Skaftár cauldrons. A third temporary array was installed during the Bárðarbunga 2014-2015 volcanic eruption near the eruption site. The aim of the array installations was to discriminate between different seismic tremor sources, namely volcanic eruptions, lava flows, hydrothermal explosions and subglacial floods (jökulhlaups). The main aim of the two arrays installed on the western margin of Vatnajökull was to study their early-warning potential through the analysis of four subglacial floods observed during the study period. The seismic vibrations associated with these floods have an emergent start, are of long duration and are referred to as tremor or high-frequency noise. Due to the lack of clear discrete onsets they cannot be located using traditional earthquake location methods. Instead clusters of seismometers (called arrays) are employed to both locate the tremor source and determine the wave type in the tremor (surface vs. body waves). The array data recorded during the Bárðarbunga eruption were used to investigate the nature of shallow, pre-eruptive, long-duration seismic tremor activity related to shallow dyke formation. The sources of the tremor were found to locate at the eruption site and under ice cauldrons which formed on the ice surface during the first weeks of the unrest. Waveform data are available from the GEOFON data centre, under network code 5L.

1 year seismological experiment at Strokkur in 2017/18

Strokkur_1yr is a one year seismological experiment realized at the most active geyser on Iceland by Eva Eibl (University of Potsdam) in collaboration with Thomas R. Walter, Phillippe Jousset, Torsten Dahm, Masoud Allahbakhshi, Daniel Müller from GFZ Potsdam and Gylfi P. Hersir from ISOR Iceland. The geyser is part of the Haukadalur geothermal area in south Iceland, which contains numerous geothermal anomalies, hot springs, and basins (Walter et al., 2018). Strokkur is a pool geyser and has a silica sinter edifice with a water basin on top, which is about 12 m in diameter with a central tube of more than 20 m depth. The aim of the seismic experiment is to monitor eruptions of Strokkur geyser from June 2017 to June 2018 using four broadband seismic stations (Nanometrics Trillium Compact Posthole 20 s). Sensors were buried 30–40 cm deep in the ground at distances of 38.8 m (G4, SE), 47.3 m (G3, SW), 42.5 m (G2, N), and 95.5 m (G1, NE) from Strokkur center. Data gaps represent 15–44 % of the records as during the winter period maintenance intervals were longer and battery drainage was high. However, at any given time, at least one station recorded the eruptions. From this dataset, converted to MSEED using Pyrocko, a catalogue of 70,000 eruptions was determined and further investigated in Eibl et al. (2020) Waveform data are available from the GEOFON data centre, under network code 7L.

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