archive-no.com » NO » N » NORSAR.NO

Total: 661

Choose link from "Titles, links and description words view":

Or switch to "Titles and links view".
  • Infrasound - NORSAR
    infrasonic arrays distributed globally As can be observed from the map only one of the stations in this network IS37 in Bardufoss northern Norway is located in the European Arctic region This station will probably be installed in 2012 Another infrasound station IS18 on Greenland is in operation but is located too far away to give any significant contribution to the regional monitoring of low magnitude events in the European

    Original URL path: http://www.norsar.no/monitoring/infrasound/ (2016-02-03)
    Open archived version from archive


  • IS37 Målselv
    Processing Example Explosion Database Regional Bulletin NUCLEAR TEST MONITORING INFRASOUND IS37 Målselv IS37 Infrasound station in Målselv The station is part of the International Monitoring System IMS with designated name I37NO The map to the right shows location of the new station as well as the operating seismic arrays PS27 and PS28 The station is now constructed and operating at the location Brannmoen in Målselv Norway The station consists of 10 measurement points each with one microbarometer of type MB2005 and a pipe array wind noise reduction system with dimension 18x18 meters A Central Facility building CRF is supplying all sites with electric power through buried copper cables Intra array communication is using fiber optic cables Each of the 10 sites will have single power and fiber cable to the CRF The fiber cables is installed in 40 mm pipes The lower right map shows the sites and the paths for the trenches required for the cables There are all together about 5200 meters of trenches and 9500 meters of cables both copper and fiber Each of the sites H0 H9 have an instrument vault plus a pipe array for wind noise suppression The site is surrounded by a 20x20

    Original URL path: http://www.norsar.no/monitoring/infrasound/IS37/ (2016-02-03)
    Open archived version from archive

  • Current Installations - NORSAR
    turned out to be quite sensitive to infrasound signals have been useful in our studies of infrasound waves The figure shows the geometry of the ARCES array Currently an experimental infrasound installation consisting of four sensors is installed at ARCES two sensors in the first ring located at ARA1 and ARA2 and two sensors in the second ring ARB2 and ARB3 Swedish network In addition to Apatity and ARCES NORSAR has access to the data from the Swedish Infrasound Network which has been in operation since the beginning of the 1970s Operated by the Swedish Institute of Space Physics the network has until recently comprised four infrasound stations Kiruna Jamton Lycksele and Uppsala The station in Uppsala was moved to Sodankyla Finland during the summer of 2006 The arrays in this network are triangular with a distance between sensors of only 75 meters The figure shows the current Nordic infrasound network along with two explosion sites Apatity Russia The Apatity seismic infrasonic array is one of the main infrasonic installations available in northern Europe The infrasonic component is a small aperture microbarographic array installed in conjunction with the seismic array near lake Imandra in the Kola Peninsula Data is digitized

    Original URL path: http://www.norsar.no/monitoring/infrasound/Other-Installations/ (2016-02-03)
    Open archived version from archive

  • Processing Example - NORSAR
    IS37 Målselv Other Installations Processing Example Explosion Database Regional Bulletin NUCLEAR TEST MONITORING INFRASOUND Processing Example Processing Example To illustrate the processing of infrasonic signals from stations in the Nordic network we show data for two of the stations Kiruna Sweden and Apatity Russia for two surface explosions in NW Russia near the Norwegian border These explosions were presumably conducted for the purpose of destroying old ammunition We record a number of such events each year from this site Kiruna data for two surface explosions Apatity data for two surface explosions Closer view of the Kiruna and Apatity data for the two surface explosions Click on image for larger version Although the Kiruna signals are clipped due to the limited dynamic range of the digitizer we have found that reliable azimuths can be easily estimated using either f k analysis or a cross correlation technique bottom left The fact that the array is very small 75 meters across does not seem to be a disadvantage at the frequencies of interest for this type of events 2 8 Hz For the Apatity array the dynamic range is much larger and the true signal can therefore be recorded The cross correlation analysis

    Original URL path: http://www.norsar.no/monitoring/infrasound/Processing-Example/ (2016-02-03)
    Open archived version from archive

  • Explosion Database - NORSAR
    Explosion site on the map below These explosions which are carried out annually in August September are presumably for the purpose of destroying old ammunition and generate unusually strong infrasonic signals in addition to seismic signals Typical seismic and infrasonic signals generated by these explosions The figure shows waveform data from the ARCES seismic array one minute prior to and 14 minutes after a surface explosion in northern Finland at a distance of approximately 175 km The top left panel shows waveforms on the central seismometer the seismic P phase A seismic Sphase B and an infrasonic arrival approximately 640 seconds after the estimated origin time C The broadband f k analysis plots right side indicate that all of these signals come from a backazimuth of about 173 degrees The bottom left panel shows P S and infrasonic array beams steered towards the epicenter and illustrates the gain in signal to noise ratio resulting from the beamforming process Click on image for larger version Time aligned signals The figure shows time aligned signals on the ARA0 sz sensor of the ARCES array for all the explosions at the northern Finland site which took place in the year 2002 The epicentral distance is 175 km A large amplitude acoustic signal approximately 600 seconds following the origin time is observed for almost all of these events but unlike the seismic signals which are almost identical for each explosion the temporal nature and amplitudes of the acoustic signals differ greatly from event to event Click on image for larger version Infrasound detection statistics The figure displays a color scaled indication of an infrasound detection statistic for the ARCES and Apatity arrays for a five minutes long time window following each event in the database of explosions at the northern Finland site during the

    Original URL path: http://www.norsar.no/monitoring/infrasound/Explosion-Database/ (2016-02-03)
    Open archived version from archive

  • Regional Bulletin - NORSAR
    MONITORING INFRASOUND Regional Bulletin Regional Bulletin We continue our work towards developing and evaluating a joint seismic infrasonic bulletin for northern Fennoscandia and adjacent regions This bulletin would be similar to the automatic seismic bulletin that we are currently providing on the NORSAR Web pages but it would also contain infrasonic phase associations Some illustrations of initial results are presented below Events where no infrasound signals were observed by ARCES or Apatity The map shows the 651 automatically located events GBF during a period of about one year for which either the ARCES seismic array or the Apatity infrasound array observed infrasound signals The blue triangles show the GBF event locations and the red stars show the location of known sites with explosions either at the Earth s surface or in the atmosphere Note that the automatic GBF locations usually scatter over a larger area around these source regions Also note that the GBF locations employ a fixed grid and that many of the grid points shown on the map have a large number of corresponding events Events for which ARCES Apatity observed infrasound signals This map is similar to the previous map and shows the 68 automatically located events

    Original URL path: http://www.norsar.no/monitoring/infrasound/Regional-Bulletin/ (2016-02-03)
    Open archived version from archive

  • Search
    norsar about us Publications 2009 Books Chapter in bookBenito M C Lindholm E Camacho A Climent G Marroquin E Molina W Rojas E Talavera J J Es Read More 2010 norsar about us Publications 2010 Books Chapter in bookPolom U L Hansen S Sauvin J S L Heureux I Lecomte C M Krawczyk M Vanneste O Long Read More 2010 norsar about us News 2010 Read More 2011 norsar about us News 2011 Read More 1 2 3 4 5 6 7 8 9 10 51 Articles found Title Achilles Joint Qualification System norsar about us News 2012 Achilles Read More AGU Fall 2009 microearthquake session norsar about us News 2009 AGU Fall 2009 microearthquake session NORSAR organizes session on microearthquakes at this years AGU Fall meeting in San Francisco Interested scientists are invited to submit manu Read More Announced Nuclear Test by North Korea norsar about us News 2009 Announced Nuclear Test by North Korea The NORSAR observatory recorded today 25 May 2009 at 01 04 24 GMT seismic signals from a presumed underground nuclear test in North Korea The test Read More Annual Report 2013 norsar about us News 2014 Annual Report 2013 Read More Arctic seismology session at ESC 2010 norsar about us News 2010 Arctic seismology session at ESC 2010 Call for Abstracts NORSAR and the Institute of Geophysics of the University of Warsaw would like to call for contributions to the followi Read More Avdelingsleder for Seismologi og Prøvestanskontroll norsar about us Careers stb manager Vi søker en dyktig avdelingsleder til vår avdeling for Seismologi og Prøvestanskontroll med evnen til å motivere til gode resultater Read More CO2 Storage Monitoring norsar about us News 2009 CO2 Storage Monitoring The key requirement to a safe storage of CO2 is to be constantly aware of the position

    Original URL path: http://www.norsar.no/monitoring/search/1/1/ (2016-02-03)
    Open archived version from archive

  • EARTHQUAKES
    EARTHQUAKES Earthquakes An earthquake is the result of a sudden release of energy in the Earth s crust that creates seismic waves The distribution of earthquakes on the Earth is not random but concentrates in belts which correspond to the three existing kinds of lithospheric plate boundaries compressional subduction zones continent continent collision extensional mid ocean ridges and transforms In terms of seismic energy approximately 98 are released at plate boundaries and thereof 80 originate from subduction zones 15 from continent continent collisions and up to 5 from mid ocean ridges The figure shows the distribution of seismicity worldwide from 1973 to 2007 The the earthquake depth is indicated by the color scale Data provided by USGS Figure plotted using GMT At the Earth s surface earthquakes manifest themselves by a shaking and sometimes displacement of the ground When a large earthquake epicenter is located offshore the seabed sometimes suffers sufficient displacement to cause a tsunami The shaking in earthquakes can also trigger landslides and occasionally volcanic activity Seismic waves released by earthquakes are generally recorded with seismometers and analyzed to report for example the moment magnitude of an earthquake The Richter magnitude was developed in 1935 by Charles Richter and Beno Gutenberg at the California Institute of Technology Since it is a logarithmic scale an increase of one magnitude implies a tenfold increase in shaking amplitude The intensity of shaking is generally measured on the modified Mercalli scale In its most generic sense the word earthquake is used to describe any seismic event whether a natural phenomenon or an event caused by humans that generates seismic waves Earthquakes are caused mostly by rupture of geological faults but also by volcanic activity landslides mine blasts nuclear experiments and production injection in hydrocarbon reservoirs The approximate energy equivalents of earthquakes in

    Original URL path: http://www.norsar.no/seismology/Earthquakes/ (2016-02-03)
    Open archived version from archive