Podrobnosti záznamu

Název
    Magma intrusions and earthquake swarm occurremce in the western part of the Bohemian Massif
Údaj o odpovědnosti
    Aleš Špičák, Josef Horálek, Alena Boušková, Čestmír Tomek, Jiří Vaněk
Autor
    Boušková, Alena
    Horálek, Josef
    Špičák, Aleš
    Tomek, Čestmír
    Vaněk, Jiří
Jazyk
    anglicky
Zdrojový dokument - seriál
    Studia geophysica et geodaetica
Svazek/č.
    Roč. 43, č. 1
Strany
    s. 87-106
Rok
    1999
Poznámky
    9 obr.
    il.
    Obsahuje bibliografické odkazy
    Zkr. název ser.: Stud. geophys. geod. (Praha)
Předmětová skupina
    bohemikum
    geologie regionální
    geotektonika
    intruze
    kenozoické vulkanity Českého masivu
    měření seizmické
    moldanubikum
    saxothuringikum
    seizmicita
    vulkanismus
    zemětřesení indukované
    zemětřesný roj
Geografické jméno
    Česká republika
    Francie
    Itálie
    SRN
Klíčové slovo
    Bohemian
    Earthquake
    Intrusions
    Magma
    Massif
    Occurremce
    Swarm
    Western
Abstrakt (anglicky)
   We are proposing a hypothesis that earthquake swarms in the West Bohemia/Vogtland seismoactive region are generated by magmatic activity currently transported to the upper crustal layers. We assume that the injection of magma and/or related fluids and gases causes hydraulic fracturing which is manifested as an earthquake swarm at the surface. Our statements are supported by hree spheres of evidence coming from the western part of the Bohemian Massif: characteristic manifestations of recent geodynamic activity, the information from the neighbouring KTB deep drilling project and from the 9HR seismic reflection profile, and the detalied analysis of local seismological data. (1) recent manifestations of geodynamic activity include Quaternary volcanism, rich CO2 emissions, anomalies of mantlederived 3He, mineral springs, moffets, etc. (2) The fluid injection experiment in the neighbouring KTB deep borehole at a depth of 9 km induced hundreds of micro-earthquakes.
   This indicates that the Earth's crust is near frictional failure in the western part of the Bohemian Massif and an addition of a small amount of energy to the tectonic stress is enough to induce an earthquake. Some pronounced reflections in the closely passing 9HR seismic reflection profile are interpreted as being caused by recent magmatic sills in the crust. (3) The local broadband seismological network WEBNET provided high quality data that enable precise localization of seismic events. The events of the January 1997 earthquake swarm are confined to an extremely narrow volume at depths of about 9 km. Their seismograms display pronounced reflections of P- and S-waves in the upper crust. The analysis of the process of faulting has disclosed a considerable variability of the source mechanism during the swarm. We conclude that the mechanism of intraplate earthquake swarms generated by magma intrusions is similar to that of induced seismicity.
   As the recent tectonic processes and manifestations of geodynamic activity are similar in European areas
Přispěvatel
    Česká geologická služba
Kód přispěvatele
    ČGS (UNM)
Zdrojový formát
    U
Datum vložení
    6. 3. 2008
Datum importu
    8. 8. 2012