Other language confidence: 0.9089977299384518
The Institute of Seismology, University of Helsinki (ISUH) was founded in 1961 as a response to the growing public concern for environmental hazards caused by nuclear weapon testing. Since then ISUH has been responsible for seismic monitoring in Finland. The current mandate covers government regulator duties in seismic hazard mitigation and nuclear test ban treaty verification, observatory activities and operation of the Finnish National Seismic Network (FNSN) as well as research and teaching of seismology at the University of Helsinki.The first seismograph station of Finland was installed at the premises of the Department of Physics, University of Helsinki in 1924. However, the mechanical Mainka seismographs had low magnification and thus the recordings were of little practical value for the study of local seismicity. The first short-period seismographs were set up between 1956 and 1963. The next significant upgrade of FNSN occurred during the late 1970’s when digital tripartite arrays in southern and central Finland became fully operational, allowing for systematic use of instrumental detection, location and magnitude determination methods. By the end of the 1990’s, the entire network was operating using digital telemetric or dial-up methods. The FNSN has expanded significantly during the 21st Century. It comprises now 36 permanent stations. Most of the stations have Streckeisen STS-2, Nanometrics Trillium (Compact/P/PA/QA) or Guralp CMG-3T broad band sensors. Some Teledyne-Geotech S13/GS13 short period sensors are also in use. Data acquisition systems are a combination of Earth Data PS6-24 digitizers and PC with Seiscomp/Seedlink software or Nanometrics Centaurs. The stations are connected to the ISUH with Seedlink via Internet and provide continuous waveform data at 40 Hz (array) or 100-250 Hz sampling frequency. Further information about instrumentation can be found at the Institute’s web site (www.seismo.helsinki.fi). Waveform data are available from the GEOFON data centre, under network code HE, and arefully open.
– A temporary seismic network consisting of 48 long-term and 15 short-term stations was deployed from June 2021 to June 2022. The network comprises 27 broadband stations and 20 short period geophones from the Ruhr-University Bochum, the Geophysical Instrument Pool Potsdam (GIPP) and the RWTH Aachen. The inter-station spacing of the longer-term network is about 2 km and the total extent of the network is about 20 km. The densely populated area and vicinity of active pit mining demanded a balance between dense station placement and avoidance of anthropogenic noise sources. The network serves as a pre-study for the installment of a field laboratory in Eschweiler-Weisweiler, Germany. Details can be found in the accompanying data publication (Finger et al., in preparation). This project has been subsidized through the Cofund GEOTHERMICA, which is supported by the European Union’s HORIZON 2020 programme for research, technological development and demonstration under grant agreement No 731117. Furthermore, this study was supported by the Interreg North-West Europe (Interreg NWE) Programme through the Roll-out of Deep Geothermal Energy in North-West Europe (DGE-ROLLOUT) Project (http://www.nweurope.eu/DGE-Rollout), NWE 892. The Interreg NWE Programme is part of the European Cohesion Policy and is financed by the European Regional Development Fund (ERDF). Waveform data are available from the GEOFON data centre, under network code ZB. Data from embargoed stations might be available on request.
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.
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.
Ketzin in a small town 20km west of Berlin that hosts a research facility for underground storage. Starting in 2008 the site was used to investigate the onshore geological storage of carbon dioxide (Liebscher et al., 2013). Among a large variety of downhole monitoring measurements and repeated 3D seismics above the storage formation, a seismic network was installed to investigate the possibility of monitoring subsurface processes related to the injection of CO2 with passive seismic recordings (Gassenmeier et al., 2015). The network was operated for 12 month from early 2011 to 2012 and consisted of 10 Guralp broadband sensors of the Geophysical Instrument Pool Potsdam (GIPP). Five instruments were located at the drilling site and five instruments were installed at a distance up to 3.5km around the injection site. The Instruments were either installed in basements or buried at a depth of about 70cm (KTE, KTF and KTG). The installation was supported by the German Federal Ministry of Education and Research (BMBF, grant 03G0736A) by the University of Leipzig and the GIPP.
We provide seismological data from a huddle test in Fürstenfeldbruck in August 2019 that was realized by University of Potsdam (PI: Eva Eibl) in collaboration with BGR (PI: Stefanie Donner) and LMU (PI: Felix Bernauer). 5 rotational sensors (blueSeis-3A) and 3 seismometers (Trillium Horizon 120s Nanometrics) were installed on a decoupled basement in a building of the Geophysical Observatory Fürstenfeldbruck. The seismometers were isolated with black foam rubber and white cotton. We recorded passive seismological data for one week and recorded noise, coherent noise sources and the August 29, 2019 ML 3.4 Dettingen earthquake. The aim of the seismic experiment is to compare the performance of rotational sensors and seismometers with respect to different coherent and incoherent noise sources. The noise level, spectral content of the coherent noise and back azimuth of the Dettingen earthquake was further investigated for all sensors using correlation, coherence analysis and probabilistic power spectral densities in Izgi et al. (2021). Waveform data are available from the GEOFON data centre, under network code X3.
“1-month seismological experiment on Etna, Italy in 2019" is a 1-month seismological experi-ment realized near the Pizzi Deneri Observatory on Etna, Italy, by Eva Eibl and Daniel Vollmer (University of Potsdam) in collaboration with Philippe Jousset from GFZ Potsdam Germany and Gilda Currenti and Graziano Larocca from INGV-OE, Italy. From August to September 2019, we recorded the volcano-seismic events accompanying the volcanic activity using a rotational sensor and a co-located seismometer. The aim of the seismological experiment was to study LP events, VT events and tremor. We used a 3-component broadband seismometer (Nanometrics Trillium Compact 120 s) and a 3-component rotational sensor (iXblue blueSeis-3A) and stored the data on a DataCube and CommunicationCube, respectively. Sensors were installed on the same 35 * 35 * 3 cm3 granitic base plate at about 40 cm depth enclosed by backfilled pyroclastic material to avoid wind noise. The instruments recorded at 200 Hz sampling rate and were located about 2 km from the craters on Etna. The setup was powered using 3 solar panels of 140W each and three batteries of 75Ah each. We oriented the rotational sensor and seismometer using a Quadrans fiber-optical gyrocompass. The Quadrans is not affected by magnetic minerals in the ground and our sensors are hence properly aligned to geographic north. We converted the seismometer data to MSEED using Pyrocko’s Jackseis program and created a catalogs of LP events and VT events that were further investigated in Eibl et al. 2022. Waveform data are available from the GEOFON data centre, under network code ZR.
"2-year seismological experiment near Fagradalsfjall, Reykjanes peninsula in 2021/22" is a two-year seismological experiment realized near the eruptive site at Fagradalsfjall on the Reykjanes peninsula, Iceland, by Eva Eibl (University of Potsdam) in collaboration with Gylfi P. Hersir, Egill Á. Gudnason and Friðgeir Pétursson from ISOR Iceland. From March to September 2021 an effusive, basaltic eruption happened in Geldingadalir near mount Fagradalsfjall on the Reykjanes peninsula. The aim of the seismic experiment was to monitor volcano-seismic signals such as LP events, VT events and tremor, before, during and after the eruption from 14 March 2021 to August 2022. We used two broadband seismometers (Nanometrics Trillium Compact 120 s) and two rotational sensors (iXblue blueSeis-3A) and stored the data on DataCubes and CommunicationCubes, respectively. Sensors were until mid-June installed on the surface and shielded from wind using a bucket. From mid-June they were buried 40cm deep in the ground at about 2 km from the eruptive vent. At any given time, at least one station recorded the seismic signals caused by the eruption. Waveform data are available from the GEOFON data centre, under network code 9F.
Building monitoring and decentralized, on-site Earthquake Early Warning system for the Kyrgyz capital Bishkek. Several low cost sensors equipped with MEMS accelerometers have been installed in eleven buildings within the urban area of the city. The different sensing units communicate with each other via wireless links and the seismic data are streamed in real-time to data centres at GFZ and the Central Asian Institute for Applied Geoscience (CAIAG) using internet. Since each sensing unit has its own computing capabilities, software for data processing can be installed to perform decentralised actions. In particular, each sensing unit can perform event detection tasks and run software for on-site early warning. If a description for the vulnerability of the building is uploaded to the sensing unit, this can be exploited to introduce the expected probability of damage in the early-warning protocol customized for a specific structure. Waveform data are available from the GEOFON data centre, under network code KD.
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.
| Organisation | Count |
|---|---|
| Weitere | 2 |
| Wissenschaft | 90 |
| Type | Count |
|---|---|
| unbekannt | 92 |
| License | Count |
|---|---|
| Geschlossen | 21 |
| Offen | 41 |
| Unbekannt | 30 |
| Language | Count |
|---|---|
| Englisch | 92 |
| Resource type | Count |
|---|---|
| Keine | 92 |
| Topic | Count |
|---|---|
| Boden | 92 |
| Lebewesen und Lebensräume | 53 |
| Luft | 26 |
| Mensch und Umwelt | 92 |
| Wasser | 19 |
| Weitere | 92 |