Seismologian instituutti

 

Recent Submissions

  • Skyttä, Pietari; Nikkilä, Kaisa; Heilimo, Esa; Kukkonen, Ilmo; Veikkolainen, Toni; Karell, Fredrik; Kozlovskaya, Elena; Luttinen, Arto; Nykänen, Vesa; Poutanen, Markku; Tanskanen, Eija; Tiira, Timo (Institute of Seismology, University of Helsinki, 2022)
    Report S-72
  • Kolehmainen, Kauri; Heinonen, Suvi; Komminaho, Kari; Tiira, Timo; Veikkolainen, Toni (Seismologian instituutti, 2022)
    Raportti ; T-107
    Seismic wide-angle refraction and reflection (WARR) surveys have been crucial in the study of the structure of the Fennoscandian shield. The valuable data and crustal seismic velocity models of major WARR studies from the 1980s to the present day have not been previously available to the public. In the work described in this report, the velocity models and wide-angle data were re-formatted to more accessible data formats and safely stored in the IDA Research Data Storage service for open access and data identification through Digital Object Identifiers. Data use is allowed under the Creative Commons By Attribution version 4.0 license. The data is also made available through the Hakku service of the Geological Survey of Finland. The velocity models are stored in a universal velocity point format in text files and wide-angle sections are stored in standard IBM SEG-Y format. A general description of WARR studies, available data and data use is given in this report.
  • Veikkolainen, Toni; Oinonen, Kati; Vuorinen, Tommi; Kortström, Jari; Mäntyniemi, Päivi; Lindblom, Pasi; Luhta, Tuija; Hällsten, Jennifer; Tiira, Timo (Seismologian instituutti, 2022)
    Raportti ; T-106
    2021 was the first fully operational year of the HelsinkiNet, a collaborative seismological observation network of the Institute of Seismology and City of Helsinki. The stations KUNI, LAUT, and VUOS continued in association with the national and regional automatic detection systems. In May 2021, operation of the station RSUO began for monitoring the geothermal heat plant of Ruskeasuo. In addition, stations HEL1-HEL5 were in operation in Helsinki and Espoo, although HEL4 stopped operating in April 2021. A total of 3483 confirmed seismic events occurred within 30 km of the Central Railway Square of Helsinki. Only one of them was a natural earthquake. It occurred in the sea area of Kirkkonummi on the 28th of August 2021. A single induced earthquake was observed in southeastern Espoo on the 2nd of March 2021, and again on the 4th of July 2021. A swarm of probably induced earthquakes occurred in the same area on the 27th and 29th of December 2021. The vast majority of observed seismic events were explosions. Particular attention was paid to a detonation in the low atmosphere in northern Pasila on the 11th of September 2021. The location and the probable reason for the event were resolved in cooperation between the Institute of Seismology and the Ursa Astronomical Association.
  • Luhta, Tuija; Oinonen, Kati; Kortström, Jari; Vuorinen, Tommi; Seipäjärvi, Pirita; Pekkala, Minttu; Veikkolainen, Toni; Lindblom, Pasi; Tiira, Timo (Seismologian instituutti, 2022)
    Raportti ; T-105
    In summer 2021 Tampereen Sähkölaitos and Tammervoma started drilling a deep geothermal well as a pilot project on the Tarastenjärvi power plant premises in Tampere. In addition to local companies the Kaupunkilämpö consortium of 15 urban energy companies from Finland is involved in the project. Main operator is Thermo Rock Oy. In the first phase of the project, the goal is to reach three kilometers depth. For seismic monitoring of the project Institute of Seismology University of Helsinki istalled a network consisting of one real-time broad-band seismic station and six geophone stations. Real-time seismic monitoring of Tarastenjärvi area was incorporated into the institute's national seismic monitoring. A procedure for fast communication to the operators and authorities monitoring the project was established in case of observed earthquakes. Within 20 kilometers from the Tarastenjärvi power plant 90 seismic events were detected and localized from the year 2021 seismic data. All were explosions from quarries or construction sites. Fifty events were detected and analysed as a part of national seismic monitoring. Magnitudes of those events were between 0.1 and 1.3 with a median of 0.7. During the project's monitoring period from May 18th to November 31st forty additional small events were detected and later analysed with data from the geophone network. Magnitudes of these events were between -0.7 and 1.3 with a median of 0.1. An automatic detector applied to geophone data revealed even more small events but no earthquakes, and none of the events were in the immediate proximity of the Tarastenjärvi power plant.
  • Veikkolainen, Toni; Oinonen, Kati; Vuorinen, Tommi; Kortström, Jari; Mäntyniemi, Päivi; Lindblom, Pasi; Uski, Marja; Tiira, Timo (Seismologian instituutti, Geotieteiden ja maantieteen osasto, Helsingin yliopisto, 2021)
    Seismologian instituutin raportti ; T-103
    In 2019–2020, the Institute of Seismology set up, in collaboration with the City of Helsinki, a seismic network, HelsinkiNet, consisting of three stations. The stations of the network were in operation in Kuninkaantammi (KUNI), Lauttasaari (LAUT), and Vuosaari (VUOS) in association with the automatic observation systems of Finland and the Helsinki region. The noise level of stations was low considering their locations, and no long interruptions to data delivery have taken place. In addition to HelsinkiNet, stations HEL1-HEL5 established for the monitoring of the St1 deep heat project were operational in the western part of Helsinki region. In 2020, the number of confirmed seismic events within 30 km from the Central Railway Station of Helsinki was 484, most of them explosions. Induced earthquakes happened in Espoo, particularly in Otaniemi, but also in Koskelo. Three natural earthquakes occurred, two of them were 0.7-magnitude events in Vantaa and one was a –0.5-magnitude event in Laajaranta. The number of natural and induced earthquakes of at least magnitude 0.0 was 24. Most of the macroseismic observations of earthquakes were associated with the St1 geothermal plant project in Otaniemi, Espoo.
  • Veikkolainen, Toni; Uski, Marja; Voutilainen, Ahti; Vuorinen, Tommi; Oinonen, Kati; Kortström, Jari; Luhta, Tuija; Mäntyniemi, Päivi; Tiira, Timo (Seismologian instituutti, Geotieteiden ja maantieteen osasto, Helsingin yliopisto, 2020)
    Seismologian instituutin raportti ; T-102
    This report describes induced seismicity related to the Otaniemi deep heat project of the energy company St1 in January-September 2020. The St1 company completed a conductivity test and a subsequent counterstimulation in the 5.8 km deep borehole OTN-2b in Espoo, Finland in May 2020. During these procedures, induced earthquakes occurred, several of which were noticed by residents. The results presented here are part of seismic monitoring of the Otaniemi enhanced geothermal system conducted by the Institute of Seismology. During the conductivity test and counter-stimulation, induced seismicity clearly remained below the 2018 levels. Nine events with magnitude ML ≥ 0.8 were observed and two of them exceeded the amber traffic light threshold (ML ≥ 1,2). Preliminary focal mechanisms indicate that the amber events occurred in a NNW-SSE fracture zone crosscutting the heat reservoir. The largest events were located within 500 m radius from the borehole, mainly at a depth of 5.4-5.6 km near the bottom of the borehole. After the water injection the level of induced seismicity decreased rapidly. Only a few weak induced events were observed in between the first and second stimulation period. Appendix 1.1 lists induced earthquakes observed instrumentally in the Helsinki region until the end of September 2020, with the threshold magnitude ML ≥ 0.8. Appendix 1.2 presents all induced earthquakes from the same area with macroseismic felt reports submitted to the Institute of Seismology, regardless of magnitude.
  • Uski, Marja; Piipponen, Kaiu (Institute of Seismology, University of Helsinki, 2020)
    Report / Institute of Seismology, University of Helsinki ; S-70
    Abstract This report is intended to serve as background material for authorities monitoring and permitting geothermal plants and their environmental impacts. Geothermal energy is a renewable energy source extracted from bedrock. Extraction of heat from old and cold Finnish bedrock is challenging and requires new technological solutions. One of the prerequisites for building a geothermal plant is deep drilling, and in some cases hydraulic stimulation, which may entail a seismic risk requiring special measures. Other factors to be considered are the safety of water bodies and groundwater areas, as well as processing of the drilling and fluid wastes during construction and production phases. This report was commissioned and funded by the Ministry of the Environment. It is written by experts from the Institute of Seismology and the Geological Survey of Finland. The aim of the report is to describe the problems and potential risks associated with deep drillholes and their usage in geothermal energy supply. The report provides permit authorities with recommendations on good practices and guidelines on permitting of the different phases of geothermal energy projects following Land Use and Building Act (132/1999). These recommendations are not binding. The first three sections of the report provide information on seismic activity and seismic monitoring in Finland, the different forms of geothermal energy and lessons learned in projects carried out in Finland by 2019. The fourth section focuses on the risk management of induced seismicity. It includes basic information on the mechanisms of induced seismicity, ground motions, risk analysis and the seismic monitoring of plants. The earthquake risk associated with a geothermal plant is at its highest when the water permeability of the bedrock is improved via hydraulic stimulation during the construction of the plant. During this phase, operations should be especially closely monitored. The fifth and sixth sections of the report provide recommendations concerning the content of permit applications, communications and the monitoring of operations. The permit application should include a seismic risk assessment of the plant area and its surroundings as well as the other potential environmental impacts of the power plant. It should also include plans for seismic monitoring, environmental monitoring, work site arrangements, drilling technique, the monitoring of operations and communications. Following lifecycle of the plant, the recommendations of the monitoring of operations are divided into three phases: the construction phase (including drilling and stimulation), the production phase and follow-up monitoring. Each phase is further divided into seismic monitoring and other environmental monitoring. All of the recommendations are also presented as concise summaries at the end of the report.
  • Uski, Marja; Piipponen, Kaiu (Institute of Seismology, University of Helsinki, 2020)
    Report ; S-69
    Sammanfattning Syftet med denna utredning är att ge bakgrundsinformation för myndighetsarbetet gällande geotermiska kraftverk och deras miljökonsekvenser. Geotermisk energi är ett växande område inom förnybar energiproduktion där Finlands tämligen kalla kristallina berggrund är en utmaning, som kräver nya tekniska lösningar. Ett geotermiskt kraftverk kräver djupborrning och till byggfasen hör ofta hydraulisk stimulering. Detta innebär en seismisk risk, vilket förutsätter specialåtgärder. Andra aspekter, bl.a. avfallshanteringen i borrnings- och produktionsfasen, bör också beaktas. Det är väsentligt att även vattentillståndet i sjöar, vattendrag och grundvattenområden observeras. Utredningen gjordes på uppdrag av miljöministeriet, som även finansierade den. I arbetet deltog experter från Seismologiska institutet och Geologiska forskningscentralen. Avsikten är att klarlägga problematiken och eventuella risker i samband med den djupborrning som behövs när geotermisk energi utvinns. I rapporten ges rekommendationer angående gott förfarande till tillståndsmyndigheterna. Dessutom ges synpunkter på vad tillsynsmyndigheten bör förutsätta av den som ansöker om bygglov eller åtgärdstillstånd enligt markanvändnings- och bygglagen (132/1999) i projektets olika faser. Synpunkter på vilka andra åtgärder myndigheten bör beakta ges också. Rekommendationerna är inte förpliktande. I början av rapporten presenteras seismiciteten och den seismiska övervakningen i Finland, samt information om olika geotermiska energiformer. Dessutom redogörs för erfarenheterna av projekt som genomförts i Finland före år 2019. Kapitel 4 behandlar riskhanteringen gällande inducerad seismicitet. Detta kapitel innehåller grundläggande information om den inducerade seismicitetens mekanismer, markrörelser, riskanalyser, samt om kraftverkens seismiska övervakning. Risken för att en geotermisk energianläggning skall orsaka en jordbävning är störst i byggfasen då man förbättrar bergets vattengenomsläpplighet genom hydraulisk stimulering. I den här fasen bör verksamheten övervakas speciellt noggrant. Rekommendationer angående tillståndsansökans innehåll, kommunikation och verksamhetsövervakning ges i kapitel 5 och 6. I samband med tillståndsansökan skall den seismiska risken i kraftverksområdet och kraftverkets eventuella övriga miljökonsekvenser utredas. Den seismiska övervakningen, miljöövervakningen, arbetsplatsarrangemangen, borrningstekniken, övervakningen av genomförandet, samt kommunikationen skall också redogöras i ansökan. Rekommendationerna för verksamhetsövervakningen ges utifrån kraftverkets livscykel för byggfasen (inklusive borrning och stimulering), produktionsfasen och efterhandsövervakningen. Varje fas är dessutom uppdelad i seismisk övervakning och annan miljöövervakning. I sammanfattningen i slutet av rapporten ges rekommendationerna i form av en koncis förteckning.
  • Luhta, Tuija; Mäntyniemi, Päivi; Vuorinen, Tommi; Lindblom, Pasi; Seipäjärvi, Pirita; Oinonen, Kati; Kortström, Jari; Tiira, Timo (Seismologian instituutti, 2020)
    Seismologian instituutin raportti ; T-101
    A three-station seismic network, HelsinkiNet, has been planned to Helsinki during 2019. The network will complement the Finnish National Seismic Network in the Helsinki region, lowering the detection treshold and improving location accuracy of seismic events. During autumn 2019 test measurements were conducted at the planned station locations. The network will be built during 2020. Institute of Seismology of the University of Helsinki (ISUH) will gather data from the stations, and perform automatic event detection. ISUH will analyse earthquakes and other significant events manually, and inform Helsinki City when necessary. In 2019 ISUH has analysed one earthquake, one induced earthquake, and 299 explosions from the Helsinki area. The earthquake (ML0.9, 59.952°N, 24.967 °E) occurred on 9th July under the sea, nearHelsinki lighthouse. The induced earthquake (ML0,6, 60.191°N, 24.841 °E) occurred on 9th May in Otaniemi, probably due to ST1 geothermal plant construction. In appendix 1 (Liite1) seismicity in Helsinki, and earthquake observations by residents there since 1829 are described.
  • Uski, Marja; Piipponen, Kaiu (Institute of Seismology, University of Helsinki, 2019)
    Report / Institute of Seismology, University of Helsinki ; S-68
  • Kukkonen, I.T.; Heinonen, S.; Silvennoinen, H.; Karell, F.; Kozlovskaya, E.; Luttinen, A.; Nikkilä, K.; Nykänen, V.; Poutanen, M.; Skyttä, P.; Tanskanen, E.; Tiira, T.; Oinonen, K. (Institute of Seismology, University of Helsinki, 2018)
    Report / University of Helsinki, Institute of Seismology ; S-67
  • Kukkonen, Ilmo; Heinonen, Suvi; Oinonen, Kati; Arhe, Katriina; Eklund, Olav; Karell, Fredrik; Kozlovskaya, Elena; Luttinen, Arto; Lahtinen, Raimo; Lunkka, Juha; Nykänen, Vesa; Poutanen, Markku; Tanskanen, Eija; Tiira, Timo (Institute of Seismology, University of Helsinki, 2016)
    Report / University of Helsinki, Institute of Seismology ; S-65
  • Eklund, Olav; Kukkonen, Ilmo; Skyttä, Pietari; Sonck-Koota, Pia; Väisänen, Markku; Whipp, David (Institute of Seismology, University of Helsinki, 2014)
    Report / University of Helsinki, Institute of Seismology ; S-62
  • Kukkonen, Ilmo; Kosonen, Emilia; Oinonen, Kati; Eklund, Olav; Korja, Annakaisa; Korja, Toivo; Lahtinen, Raimo; Lunkka, Juha Pekka; Poutanen, Markku (Institute of Seismology, University of Helsinki, 2012)
    Report / University of Helsinki, Institute of Seismology ; S-56
  • Heikkinen, Pekka; Arhe, Katriina; Korja, Toivo; Lahtinen, Raimo; Pesonen, Lauri J.; Rämö, Tapani (Institute of Seismology, University of Helsinki, 2010)
    Report / University of Helsinki, Institute of Seismology ; S-55
  • Korja, Toivo; Arhe, Katriina; Kaikkonen, Pertti; Korja, Annakaisa; Lahtinen, Raimo; Lunkka, Juha Pekka (Institute of Seismology, University of Helsinki, 2008)
    Report / University of Helsinki, Institute of Seismology ; S-53
  • Kukkonen, Ilmo T.; Eklund, Olav; Korja, Annakaisa; Korja, Toivo; Pesonen, Lauri J.; Poutanen, Markku (Institute of Seismology, University of Helsinki, 2006)
    Report / University of Helsinki, Institute of Seismology ; S-46
  • Ehlers, Carl; Eklund, Olav; Korja, Annakaisa; Kruuna, Annika; Lahtinen, Raimo (Institute of Seismology, University of Helsinki, 2004)
    Report / University of Helsinki, Institute of Seismology ; S-45
  • Lahtinen, Raimo; Korja, Annakaisa; Arhe, Katriina; Eklund, Olav; Hjelt, Sven-Erik; Pesonen, Lauri J. (Institute of Seismology, University of Helsinki, 2002)
    Report / University of Helsinki, Institute of Seismology ; S-42
  • Pesonen, Lauri J.; Korja, Annakaisa; Hjelt, Sven-Erik (Institute of Seismology, University of Helsinki, 2000)
    University of Helsinki, Institute of Seismology, Report ; S-41