{
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"# Analyzing seismicity in the West of Germany - Lower Rhine Graben and Ruhr Area"
]
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"source": [
" Vincent Enders \n",
"\n",
""
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"
This analysis will focus on two neighboring regions in the state of Northrine-Westphalia (NRW) in the West of Germany with very different tectonic settings. The first region considered is the Lower Rhine Graben (German: Niederrheinische Bucht), which consists roughly of the region bounded by the towns of Bonn, Köln (Cologne), Aachen, Düsseldorf (Dusseldorf), Bocholt and the Dutch border. The tectonic setting of the Lower Rhine Graben continues into parts of the Netherlands (cf. e.g. Klostermann et al. 1998).
\n", "The Lower Rhine Graben is part of the European Cenozoic Rift System that consists of different graben structures in France, Germany, the Netherlands and Czech Republic (cf. e.g. Schwarz 2005). The European continent is located inside a stress field dominated by the northbound movement of the African plate and the spreading of the Atlantic ocean, which causes a movement of the European plate in the opposite direction (Grünthal 2004, Schneider 2013). These large scale plate movements lead e.g. to the formation of the Alps, but also to strain in the middle of the European continent. This strain causes graben formation in Europe. Within those grabens, a major Northwest-Southeast stress field (Ahorner, Murawski and Schneider 1972) leads to further fragmentation and the formation of a fault system that is also typical for the Lower Rhine Graben (cf. e.g. Ahorner 1962, where also a map of the fault system can be found).
\n", "The Lower Rhine Graben is a seismicly active region. In general, despite mining activities (open-pit mines) in the Lower Rhine Graben, most earthquakes in this region can be directly linked to faults (Ahorner, Murawski and Schneider 1970). Most recent earthquakes were the $M_L=5.9$ earthquake near the town of Roermond (Netherlands) that caused damage worth 150 million Deutsche Mark (approximately 90 million USD) in the German part of the Lower Rhine Graben on April 13, 1992 (Meidow 1995, GD NRW: https://www.gd.nrw.de/zip/gg_erdbeben-roermond.pdf) and the $M_L=4.8$ earthquake near Alsdorf (Germany) on July 22, 2002 (GD NRW: https://www.gd.nrw.de/zip/gg_erdbeben-alsdorf.pdf), which will be analyzed in this code. Even stronger was the earthquake near the city of Düren in 1756 with a reconstructed magnitude of $M_L=6.1$ that was felt in towns as far as Paris and Halle (Meidow 1995). More recent palaeseismologic studies even lead to the conclusion that earthquakes with magnitudes of up to $M_L=7.0$ have occured in prehistoric times and are still possible in the Lower Rhine Graben (Skupin et al. 2008, Pelzing 2008). Since the West of NRW is one of the most densely populated regions in Germany, a good knowledge of the tectonic setting is vital.
" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "In contrast to this, the neighboring Ruhr area (German: Ruhrgebiet) is not part of any large-scale tectonic system. Old thrust and normal faults as well as fold structures can be found, but those structures are dormant and no tectonic earthquakes occur in the Ruhr area (Bischoff et al. 2010). However, about 1000 earthquakes with a magnitude range of $0.7\\leq M_L \\leq 3.3$ are registered every year (Bischoff et al. 2010). The strongest recorded event, a magnitude $M_L=3.3$ earthquake near the town of Moers on December 12, 2007, will be studied in the following code.
\n", "All earthquakes in the Ruhr area are temporally and spatially correlated with mining activities (Bischoff et al. 2010). Typical locations are fractures parallel to longwalls, but focal mechanisms linked to failure of remnant pillars or reactivation of older faults have been found as well (Alber et al. 2009, Bischoff et al. 2020). The spatial correlation between earthquakes and mining activities will be investigated in this code. The Ruhr area, consisting of the towns of Duisburg, Essen, Bochum, Dortmund, Hamm and their surroundings (see map below), used to be the largest coal mining area in Germany. Mining activities started in this area in the 13th century. Modern mines were located at a depth between 700 and 1500 meters below the ground and used the longwall mining technique (Bischoff et al. 2010). The last coal mine in the Ruhr area was closed in 2018 ( https://www.rag.de/news/t2_news/eine-aera-geht-zu-ende-deutschland-nimmt-abschied-vom-heimischen-steinkohlenbergbau/ ).
\n", "Sources:
\n", "Ahorner, L.: Untersuchungen zur quartären Bruchtektonik der Niederrheinischen Bucht. Eiszeitalter und Gegenwart, Vol. 13, 1962, pp. 24-105.
\n", "Ahorner, L., Murawski, H. and Schneider, G.: Die Verbreitung von schadenverursachenden Erdbeben auf dem Gebiet der Bundesrepublik Deutschland. Versuch einer seismologischen Regionalisierung. Zeitschrift für Geophysik, No. 36, 1970, pp. 313-343.
\n", "Ahorner, L., Murawski, H. and Schneider, G.: Seismotektonische Traverse von der Nordsee bis zum Apennin. Geologische Rundschau, Vol. 61, 1972, pp. 915-942.
\n", "Alber, M. et al.: Rock mechanical investigations of seismic events in a deep longwall coal mine. International Journal of Rock Mechanics & Mining Sciences 46, 2009, pp. 408–420.
\n", "Bischoff, M. et al.: Coal Mining Induced Seismicity in the Ruhr Area, Germany. Pure and Applied Geophysics 167, 2010, pp. 63–75.
\n", "Grünthal, Gottfried: Erdbeben und Erdbebengefährdung in Deutschland sowie im europäischen Kontext. Geographie und Schule 151, 2004, pp. 14-23.
\n", "Klostermann, J., Kremers, J. and Röder, R.: Rezente tektonische Bewegungen in der Niederrheinischen Bucht. Fortschritte in der Geologie von Rheinland und Westfalen, Vol. 37, 1998, pp. 557-571.
\n", "Meidow, H.: Rekonstruktion und Reinterpretation von historischen Erdbeben in den nördlichen Rheinlanden unter Berücksichtigung der Erfahrungen bei dem Erdbeben von Roermond am 13. April 1992. Dissertation at Universität zu Köln, 1995.
\n", "Pelzing, R.: Erdbeben in Nordrhein-Westfalen. Publication of Geologischer Dienst Nordrhein-Westfalen, 2008.
\n", "Schneider, G.: Erdbeben. Eine Einführung für Geowissenschaftler und Bauingenieure. Elsevier/Spektrum Akademischer Verlag, 2013.
\n", "Schwarz, M.: Evolution und Struktur des Oberrheingrabens - quantitative Einblicke mit Hilfe dreidimensionaler thermomechanischer Modellrechnungen. Dissertation at University of Freiburg im Breisgau, 2005.
\n", "Skupin, K. et al.: Paläoseismische Untersuchungen im Bereich der Niederrheinischen Bucht. Scriptum 17, Arbeitsergebnisse aus dem Geologischen Dienst Nordrhein-Westfalen, 2008, pp. 5-72.
\n", "Zahn, U. et al.: Diercke Weltatlas, 4th edition. Westermann Katographie, 1996.
\n", "\n", "In addition to the course material from IRIS, I have studied the following tutorials to create the code presented in this work:
\n", "https://contextily.readthedocs.io/en/latest/index.html
\n", "https://geopandas.readthedocs.io/en/latest/index.html
\n", "https://stackoverflow.com/questions/54088858/plotting-a-map-using-geopandas-and-matplotlib
\n", "https://geopandas.org/gallery/create_geopandas_from_pandas.html
\n", "\n", "https://towardsdatascience.com/easy-steps-to-plot-geographic-data-on-a-map-python-11217859a2db
\n", "The author of this document is not responsible for the content of the webpages listed under any of the links in this document.
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