TY - GEN A1 - Donner, Stefanie A1 - Rößler, Dirk A1 - Strecker, Manfred A1 - Landgraf, Angela A1 - Ballato, Paolo T1 - Erweiterte Momententensorinversion und ihre seismotektonische Anwendung : Elbursgebirge, Nordiran T1 - Extended moment tensor inversion and its seismotectonic application : Alborz Mountains, Northern Iran N2 - Der Elburs im Norden Irans ist ein durch die Konvergenz der Arabischen und Eurasischen Platte verursachtes doppelt konvergentes Gebirge. Das komplexe System von Blattverschiebungen und Überschiebungen sowie die Aufnahme der Deformation im Elburs ist noch nicht sehr gut verstanden. Eine neu zu entwicklende Methode zur Inversion von seismischen Momententensoren, die unterschiedliche Beobachtungen verschiedener Stationstypen kombiniert invertiert, soll die bisher hauptsächlich strukturelle/geomorphologische Datengrundlage um Momententensoren auch kleinerer Magnituden (M < 4.5) erweitern. Dies ist die notwendige Grundlage für detaillierte seismotektonische Studien, die wiederum die Basis für seismische Gefährdungsanalysen bilden. KW - Momententensor KW - Iran KW - Seismotektonik KW - moment tensor KW - Iran KW - seismotectonics Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-29308 ER - TY - GEN A1 - Donner, Stefanie A1 - Strecker, Manfred A1 - Rößler, Dirk A1 - Ghods, Abdolreza A1 - Krüger, Frank A1 - Landgraf, Angela A1 - Ballato, Paolo T1 - Earthquake source models for earthquakes in Northern Iran N2 - The complex system of strike-slip and thrust faults in the Alborz Mountains, Northern Iran, are not well understood yet. Mainly structural and geomorphic data are available so far. As a more extensive base for seismotectonic studies and seismic hazard analysis we plan to do a comprehensive seismic moment tensor study also from smaller magnitudes (M < 4.5) by developing a new algorithm. Here, we present first preliminary results. KW - Elburs KW - Iran KW - Momententensor KW - Seismotektonik KW - Alborz KW - Iran KW - moment tensor KW - seismotectonics Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-32581 ER - TY - JOUR A1 - Rößler, Dirk A1 - Krüger, Frank A1 - Rümpker, Georg A1 - Psencik, Ivan T1 - Tensile source components of swarm events in West Bohemia in 2000 by considering seismic anisotropy N2 - Earthquake swarms occur frequently in West Bohemia, Central Europe. Their occurrence is correlated with and propably triggered by fluids that escape on the earth's surface near the epicentres. These fluids raise up periodically from a seemingbly deep-seated source in the upper mantle. Moment tensors for swarm events in 1997 indicate tensile faulting. However, they were determined under assumption of seismic isotropy although anisotropy can be observed. Anisotropy may obscure moment tensors and their interpretation. In 2000, more than 10,000 swarm earthquakes occurred near Novy Kostel, West Bohemia. Event triggering by fluid injection is likely. Activity lasted from 28/08 until 31/12/00 (9 phases) with maximum ML=3.2. High quality P-wave seismograms were used to retrieve the source mechanisms for 112 events between 28/08/00 and 30/10/00 using > 20 stations. We determine the source geometry using a new algorithm and different velocity models including anisotropy. From inversions of P waves we observe ML<3.2, strike-slip events on steep N-S oriented faults with additional normal or reverse components. Tensile components seem to be evident for more than 60% of the processed swarm events in West Bohemia during the phases 1-7. Being most significant at great depths and at phases 1-4 during the swarm they are time and location dependent. Although tensile components are reduced when anisotropy is assumed they persist and seem to be important. They can be explained by pore-pressure changes due to the injection of fluids that raise up. Our findings agree with other observations e.g. correlation of fluid transport and seismicity, variations in b-value, forcing rate, and in pore pressure diffusion. Tests of our results show their significance. KW - Seismologie KW - Erbeben KW - Momententensor KW - Anisotropie KW - Vogtland KW - Seismology KW - tensile earthquake KW - moment tensor KW - anisotropy KW - West Bohemia Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12975 ER -