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Found 8 results.

A database of caldera collapse analogue models stretched under extensional conditions

This dataset presents the raw data from one experimental series (named CCEX, i.e., Caldera Collapse under regional Extension) of analogue models performed to investigate the process of caldera collapse followed by regional extension. Our experimental series tested the case of perfectly circular collapsed calderas afterward stretched under regional extensional conditions, that resulted in elongated calderas. The models are primarily intended to quantify the role of regional extension on the elongation of collapsed calderas observed in extensional settings, such as the East African Rift System. An overview of the performed analogue models is provided in Table 1. Analogue models have been analysed quantitatively by means of photogrammetric reconstruction of Digital Elevation Model (DEM) used for 3D quantification of the deformation, and top-view photo analysis for qualitative descriptions. The analogue materials used in the setup of these models are described in Montanari et al. (2017), Del Ventisette et al. (2019), Bonini et al., 2021 and Maestrelli et al. (2021a,b).

A database of analogue models testing the interaction between magmatic intrusion-related doming and caldera collapse

This dataset presents the raw data from one experimental series (named CCEX, i.e., Caldera Collapse under regional Extension) of analogue models performed to investigate the process of caldera collapse followed by regional extension. Our experimental series tested the case of perfectly circular collapsed calderas afterward stretched under regional extensional conditions, that resulted in elongated calderas. The models are primarily intended to quantify the role of regional extension on the elongation of collapsed calderas observed in extensional settings, such as the East African Rift System. An overview of the performed analogue models is provided in Table 1. Analogue models have been analysed quantitatively by means of photogrammetric reconstruction of Digital Elevation Model (DEM) used for 3D quantification of the deformation, and top-view photo analysis for qualitative descriptions. The analogue materials used in the setup of these models are described in Montanari et al. (2017), Del Ventisette et al. (2019), Bonini et al., 2021 and Maestrelli et al. (2021a,b).

DEEPEN, Western DAS Branch

From June to August 2021 the DEEPEN project deployed a dense seismic network across the Hengill geothermal area in southwest Iceland to image and characterize faults and high-temperature zones at high resolution. The nodal network comprised 498 geophone nodes spread across the northern Nesjavellir and southern Hverahlíð geothermal fields and was complemented by an existing permanent and temporary backbone seismic network of a total of 44 short-period and broadband stations. In addition, two fiber optic telecommunication cables near the Nesjavellir geothermal power plant were interrogated with commercial DAS-interrogators. The here published dataset contains a subset of the downsampled DAS-recordings from the western fiber optic array. The original data were downsampled from 2000Hz to 250 Hz using the das-convert tool (https://doi.org/10.5880/GFZ.2.1.2021.005). Note that there was a problem with the GNSS timing in the original recorded data which caused significant temporal drift. This has mostly been corrected in the downsampled data, but some residual timing error may exist. Waveform data is available from the GEOFON data centre, under network code 1D, and is fully open.

GeoLab

GeoLab is a single 57km-long dark optic fibre starting at Funchal. It is equipped with a ASN OptoDAS interrogator. The acquisition parameters are: 500 Hz sampling rate, 10 metre gauge length , 5 metre channel spacing. Waveform data is available from the GEOFON data centre, under network code 3X.

Temporary DAS Deployment associated with the DEEPEN project in the Hengill region, Iceland (DEEPEN)

From June to August 2021 the DEEPEN project deployed a dense seismic nodal network across the Hengill geothermal area in southwest Iceland to image and characterize faults and high-temperature zones at high resolution. The nodal network comprised 498 geophone nodes spread across the northern Nesjavellir and southern Hverahlíð geothermal fields and was complemented by an existing permanent and temporary backbone seismic network of a total of 44 short-period and broadband stations. In addition, two fiber optic telecommunication cables near the Nesjavellir geothermal power plant were interrogated with commercial DAS-interrogators. During the time of deployment, a vibroseis survey took place around the Nesjavellir power plant. The here published dataset contains a subset of the downsampled DAS-recordings from the eastern fiber optic array. To save storage space, only every fourth trace was made available. The original data were downsampled from 1000Hz to 250 Hz using the das-convert tool (https://doi.org/10.5880/GFZ.2.1.2021.005). Further traces or the original data can be obtained upon request. Waveform data are available from the GEOFON data centre, under network code ZH.

A database of R-R-R triple junction analogue and numerical models

This dataset presents the raw data from two experimental series of analogue models and four numerical models performed to investigate Rift-Rift-Rift triple junction dynamics, supporting the modelling results described in the submitted paper. Numerical models were run in order to support the outcomes obtained from the analogue models. Our experimental series tested the case of a totally symmetric RRR junction (with rift branch angles trending at 120° and direction of stretching similarly trending at 120°; SY Series) or a less symmetric triple junction (with rift branches trending at 120° but with one of these experiencing orthogonal extension; OR Series), and testing the role of a single or two phases of extension coupled with effect of differential velocities between the three moving plates. An overview of the performed analogue and numerical models is provided in Table 1. Analogue models have been analysed quantitatively by means of photogrammetric reconstruction of Digital Elevation Model (DEM) used for 3D quantification of the deformation, and top-view photo analysis for qualitative descriptions. The analogue materials used in the setup of these models are described in Montanari et al. (2017), Del Ventisette et al. (2019) and Maestrelli et al. (2020). Numerical models were run with the finite element software ASPECT (e.g., Kronbichler et al., 2012; Heister et al., 2017; Rose et al., 2017).

Fibre-optic distributed acoustic sensing, seismological and infrasonic data set from Etna, Italy

Understanding physical processes prior and during eruptions remains challenging, due to uncertainties about subsurface structures and undetected processes within the volcano. Here, the authors use a dedicated fibre-optic cable to obtain strain data and identify volcanic events and image hidden near-surface volcanic structural features at Etna volcano, Italy. In the paper Jousset et al. (2022), we detect and characterize strain signals associated with explosions, and we find evidences for non-linear grain interactions in a scoria layer of spatially variable thickness. We also demonstrate that wavefield separation allows us to incrementally investigate the ground response to various excitation mechanisms, and we identify very small volcanic events, which we relate to fluid migration and degassing. We recorded seismic signals from natural and man-made sources with 2-m spacing along a 1.5-km-long fibre-optic cable layout near the summit of actives craters of Etna volcano, Italy. Those results provide the basis for improved volcano monitoring and hazard assessment using DAS. This data publication contains the full data set used for the analysis. This data set comprises strain-rate data from 1 iDAS interrogator (~750 traces), velocity data from 15 geophones and 4 broadband seismometers, and infrasonic pressure data from infrasound sensors. For further explanation of the data and related processing steps, please refer to Jousset et al. (2022). Waveform data are available from the GEOFON data centre, under network code 9N.

MAGIC (Magma Iceland)

In January 2020, a swarm of earthquakes started under Thorbjorn volcano, Reykjanes, SW Iceland, associated to the uplift of up to 0.5 cm per day. Concern in Iceland was growing and the Iceland Meteorological Office suggested at that time that possibly magma intruded in the crust at shallow depth (3 to 9 km). The first eruption occurred on 19.03.2021, followed by many others in the foolwing years. The GFZ started a seismological Hazard and Risk Team (HART), as soon as February 2020 in cooperation with IMO, ISOR and the University of Iceland. The interrogator was located in Grindavik and was connected to a standard telecom cable. The full data dataset of this 5J network comprise 250 Tb of raw data. The standard infrastructure is not designed for such large data set. Therefore, we implement here several datasets, corresponding to several processing and associated publications. Specific full data set is available upon request to the authors. In Flovenz et al., 2022, the data subset comprise a selection of wave-forms recorded along an optical fibre of 21 km length. The subset consists of 40 channels at 100 Hz (spatially stacked 9x). The whole time period from January until August 2020 is covered, with a total size of 496 GB. The data is MiniSEED at 4096 bytes record length with STEIM2. In Maass et al., 2024, the data subset consists of two sections of contiguous channels (1701-2000 and 3921-4218, spatial sampling 4 meters) of dynamic strain rate down sampled at 5 Hz. The whole time period from January until August 2020 is covered, with a total size of 340 GB. The data is MiniSEED at 4096 bytes record length with STEIM2.

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