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.
The NEARESTproject (Integrated observations from NEAR shore sourcES of Tsunamis: towards an early warning system) aimed at the identification and characterization of potential near-shore sources of tsunamis in the Gulf of Cadiz. This area is well known from the catastrophic earthquake and tsunami that destroyed Lisbon and several other places mainly along the EastAtlantic coast on November 1st, 1755. One of the project's work packages dealed with monitoring of recent seismic activity in the Gulf of Cadiz area. For this purpose 24 broadband ocean-bottom seismometers (OBS) from the German DEPAS instrument pool were deployed for 11 months in addition to the GEOSTAR multi-parameter deep-sea observatory and two temporary land stations in Portugal. The GEOSTAR observatory and the 24 OBS were deployed and recovered during two expeditions with RV Urania in 2007 and 2008. The OBSs consist of three‐component Guralp CMG‐40T‐OBS seismometers and HighTech HTI‐04‐PCA/ULF hydrophones. A wide range of signals was recorded, ncluding teleseismic, regional and local earthquakes, and low‐frequency (∼20 Hz) vocalization of fin whales. The GEOSTAR observatory was again deployed between 2009 and 2011. The Portuguese temporary land station PDRG was additionally recording during the NEAREST project. Originally, the position of recovery on deck was taken to calculate the mean coordinate of the OBS at depth from deployment and recovery coordinates. In most cases the difference in coordinates between deployment and recovery is very small (table 3 and 4 in Carrara et al., 2008). For two stations, the location at the seafloor could be measured by triangulation (Carrara et al., 2008). Due to experience of other experiments over the years, we finally suggest to use the deployment coordinates as the station coordinates for all stations that could not be tri-angulated. The clocks were synchronized with GPS time before the deployment and if possible again after the recovery. Unfortunately, most of the batteries were empty at the end of the recording period. That either made it impossible to realize the second synchronisation (skew time measurement) or in some case also caused erroneous synchronisations. Therefore, the internal clock drift was estimated by ambient noise analysis (Corela, 2014). The internal clock drifts were corrected using a linear interpolation method. Generally, the data quality is very good, especially for the intended study of local and regional earthquakes. Studies relying on wideband seismological recordings can also be carried out. The sensor package and noise conditions hamper the use for broadband and very broadband applications. Unfortunately, also not all channels operated properly, therefore hampering the use of multi-component methods for the relevant stations. We thank the captain E. Gentile, crew, G. Carrara, and all participants of the R/V URANIA expeditions in 2007 and 2008. We are grateful to all people and institutions involved in the NEAREST project. Waveform data is available from the GEOFON data centre, under network code 9H.
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.
– 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.
The Geological Survey of Estonia (EGT) maintains the Estonian National Seismic Network (EESN) under the network code EE. EGT is responsible of seismic monitoring of Estonia as a part of the national environmental monitoring program. Routine seismic analysis is performed in integrated co-operation with the Institute of Seismology, University of Helsinki (ISUH), and detected events are published in ISUH bulletins. The network dates back from 1980 and digital data exist from 1996 on. Initially, only one to three stations were operational. From 2015 on, the network has been expanded using temporary stations. By 2025, eight permanent and two temporary EE stations operate in real time. VSU is a joint station with GEOFON, labelled both as a GE and an EE station. Three older Estonian stations are equipped with Streckeisen STS-2 and Güralp CMG-6T seismometers. Newer sites have Nanometrics Trillium Compact sensors. Data acquisition systems are a combination of Earth Data digitizers and PC with Seiscomp software or Nanometrics Centaurs. Data sampling frequencies are 100 Hz or 250 Hz. Waveform data under network code EE are available from the GEOFON data centre and are fully open.
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.
Cliffs line many erosional coastlines. Localized failures can cause land loss and hazard, and impact ecosystems and sediment routing. Links between cliff erosion and forcing mechanisms are poorly constrained, due to limitations of classic approaches. Combining multi-seasonal seismic and drone surveys, wave, precipitation and groundwater data we study drivers and triggers of seismically detected failures along the chalk cliffs on Germany's largest island, Rügen. The network consists of four (later five) seismic stations along the 8.6 km long chalk cliff coast. Waveform data are available from the GEOFON data centre, under network code 4K.
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.
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.
| Organisation | Count |
|---|---|
| Weitere | 2 |
| Wissenschaft | 147 |
| Type | Count |
|---|---|
| unbekannt | 149 |
| License | Count |
|---|---|
| Geschlossen | 46 |
| Offen | 67 |
| Unbekannt | 36 |
| Language | Count |
|---|---|
| Englisch | 149 |
| Resource type | Count |
|---|---|
| Keine | 149 |
| Topic | Count |
|---|---|
| Boden | 148 |
| Lebewesen und Lebensräume | 83 |
| Luft | 44 |
| Mensch und Umwelt | 149 |
| Wasser | 44 |
| Weitere | 149 |