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Found 143 results.

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.

VECTOR seismic array in the Irish Midlands

A network of 210 continuously running, digital seismic stations equipped with short-period sensors (200 stations) and broadband sensors (10 stations) was deployed in an area of ~8 x ~6 km in the Irish Midlands (north of Collinstown) for a time period of ~6 weeks. The network was part of the EU project VECTOR (https://vectorproject.eu) aiming to investigate – among others – possible solutions for least invasive forms of exploration for mineral resources. In this context the collected data was mainly used to derive a 3D model of the subsurface (seismic shear wave velocity) using ambient noise tomography (down to ~1.5km depth). We thank all field crews for their excellent work rendered to the project. Waveform data is available from the GEOFON data centre, under network code 7W.

Monitoring water flow in karst using passive seismic 'listening'

Detecting and quantifying water flow structures in heterogeneous karst through geophysical imagery of karst structures, is open to large uncertainties. Here we determine that subterranean flow-induced seismic signal originating in karst subsurface water pathways such as fractures, conduits and caves can be detected as persistent frequencies on spectrograms. Conducting passive seismic surveys on two karst sites with shallow and deep conduits show that these frequencies are site dependent, and differ from what might be expected from surface water flow in rivers. We applied an amplitude-based location method to locate this flow-induced micro-tremor. Numerical simulation of the elasto-acoustic wave propagation in a simplified karst model shows that resonance plays an important role, excited by specific frequencies in the flow-related seismic spectrum. This study introduces a novel approach for detecting the flowing structures in karst by directly imaging the source itself rather than inferring flow pathways through geophysical imaging of karst structures. Waveform data is available from the GEOFON data centre, under network code 3V.

Deep OCean Test ARray DOCTAR (OBS part)

This is the first deployment of a teleseismic broadband array consisting of 12 three-component stations with an aperture of about 50 km in the deep ocean in about 5000 m water depth. The data can be compared with two other deployments on Madeira and in western Portugal mainland which had similar array layouts and recording time spans (network Y7). The broadband data enable furthermore analysis of the crust and upper mantle beneath the array near to the Gloria fault, a major transform fault in the North Atlantic. Recordings of numerous local and regional earthquakes make a precise location of active structures possible. Waveform data is available from the GEOFON data centre, under network code 3J.

EnvSeis project, Kåfjord

This network of sixteen geophones and six broadbands was installed in Kåfjord, Troms og Finnmark, Norway, to study two rockslides: Njárgavárri and Indre Nordneset. Each study site had three broadbands from September 2023 to June 2025. In addition, were installed and recording: September – November 2023: six geophones on each site; April – August 2024: four geophones at Njárgavárri and ten at Indre Nordneset. The geophones were installed locally around the rockslides while the broadbands were installed one to a few kilometers from the rockslides (except for one of them directly at Indre Nordneset). The geophones in Njárgavárri were first installed as two triangular antennas of four stations each (three in triangle and one in the middle) and were then replaced by a small aperture array around the most active part of the unstable slope. The goal was to record all activities: rock falls, cracking and creeping movements. In Indre Nordneset, the geophone stations were placed in a small aperture array all around the main scarp and surface of failure to record the cracking activity. The geophones are of type 3-D Geophone PE-6/B with DATA-CUBE3 (built-in GPS). The broadbands are of type STS-2.5 with EDR-10 digitizers. Sampling frequency was 400 Hz for geophone stations, 200 Hz broadbands. Gain was at 16 (15.258789 nV/count) for the geophone stations, set on high (100 nV/bit) for the broadband stations. Waveform data is available from the GEOFON data centre, under network code 8I.

Eifel Large-N contribution of temporary stations by the Goethe University Frankfurt

Temporary stations of the Goethe University Frankfurt as contribution to the virtual network _EIFELLNX. Waveform data is available from the GEOFON data centre, under network code 6X.

SEAMSTRESS: DEPAS ocean-bottom seismometer operations on Vestnesa Ridge in 2020-2021

“This ocean-bottom seismometer deployment is part of the SEAMSTRESS project examining tectonic stress effects on Arctic methane seepage. The project is led by PI Andreia Plaza-Faverola at the Centre for Arctic Gas Hydrates, University of Tromsö, Norway. A total of 10 ocean bottom seismometers (OBS) were deployed on Vestnesa Ridge, a sediment drift body just north Knipovich Ridge at its intersection with the Molloy Transform fault (cruise CAGE-20-5). The aim of the experiment was to look for stress release along faults that control seepage sites on Vestnesa Ridge. The network consisted of 8 Lobster type broadband OBS from the German Instrument Pool for Amphibian Seismology (DEPAS) and 2 3C geophones provided by the University of Tromsö. Instruments were free-fall deployed and spaced by about 10 km. They recorded continuously at 100 Hz for 11 months between August 2020 and July 2021.Short, intersecting refraction profiles were shot across all OBS stations, such that OBS positions at the seafloor could be determined within 10 m (cruise CAGE-21-3). Clock drift in this experiment was nonlinear and skew values were only obtained for 6 of the stations. Skew-corrected station VSN01 served as reference station to obtain the clock drift of all other stations using noise cross-correlation and subsequently correct also for the thus determined nonlinearity of time drift. Waveform data are available from the GEOFON data centre, under network code Y9.

BEAR ISLAND: DEPAS ocean-bottom seismometer operations in the Fram Strait in 2007-2008

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.

3 Days of Active Experiment using 8 Rotational Sensors and 5 Seismometers in November 2019:

We provide seismological data from a huddle test in Fürstenfeldbruck in November 2019 that was realized by University of Potsdam in collaboration with BGR and LMU. 8 rotational sensors (blueSeis-3A) were installed in a bunker beside FUR station (Streckeisen STS2.5) at the Geophysical Observatory of the Ludwig-Maximilians University Munich on the first day. For the second day the 8 rotational sensors were distributed in the field and co-located with 5 seismometers (Trillium Horizon 120s Nanometrics). The sensors were placed onto a rigid monument that consists of a 50 × 50 × 5 cm³ concrete plate.We recorded 2 fired explosions on the first day and 3 on the second day along with a vibroseis truck. The aim of the seismic experiment is to compare the performance of rotational sensors and seismometers with respect to different active sources. Waveform data is available from the GEOFON data centre, under network code 6V.

Identification and Assessment of Deep Geothermal Heat Resources in Challenging Urban Environments (GEO_URBAN)

The ability to use geothermal resources to generate heat in urban areas where the demand is greatest has the potential to significantly reduce our reliance on fossil fuels, and to support sustainable energy policies. Potential deep geothermal resources in challenging, lower-enthalpy EU settings remain poorly understood and largely untapped. The GEO-URBAN project aims to explore the potential for low enthalpy geothermal in urban environments. The project will focus on two target locations – Dublin, Ireland and Vallès, Spain – and will provide a feasibility analysis for the commercial development of deep geothermal resources in these regions. The overall objective of GEO-URBAN is to identify the geothermal resources available in two challenging urban locations and to demonstrate a commercialisation strategy that has the potential to be adapted in other similar locations. Waveform data is available from the GEOFON data centre, under network code 1V, and is {fully open.

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