Swarm of earthquakes

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As earthquake swarm or earthquake swarms in the will Geophysics some form of earthquakes designated series. Several earthquakes occur in certain regions of the earth's crust within a limited period of time. The quakes are usually of similar strength and their accumulation can last for several days to about a year.

A characteristic feature is often a slow rise and fall of seismic activity over time, which is not subject to any known law. Since the magnitudes of the earthquakes of an earthquake swarm differ only slightly, the seismicity cannot be divided into pre-, main- and aftershocks .

Overview of the swarmquakes in May and June 2014 in the German-Czech border area. The colors red, orange and yellow indicate the depth of the respective epicenter in kilometers.

The term earthquake swarm was first used by Josef Knett in 1899 in a treatise on an accumulation of more than 100 macroseismically perceived earthquakes in the Vogtland / West Bohemia region, which occurred within five weeks in 1824. There were stronger earthquakes in the region in 1897, 1903, 1908, 1936 and 1962, 1985 and 2000. In the winter of 1985/1986 the strongest earthquake recorded so far was in Vogtland / Bohemia, which reached a magnitude of 4.6 on the Richter scale . The series of earthquakes in 2014 showed similar values ​​for which magnitudes of 4.2 to 4.6 are given. The epicenter of this quake was near the Czech town of Nový Kostel at a depth of 8.5 kilometers. The last series of swarm quakes occurred in January 2019.

Earthquake swarms occur worldwide mainly in volcanically active regions. It is therefore believed that they are caused by the movement of fluids in the earth's crust . Artificially caused swarms of micro-earthquakes were also B. observed during oil production and pressure tests in deep boreholes.

Occurrence in Germany

In Germany there are swarms of earthquakes z. B. in Vogtland , in Hesse near Groß-Gerau and near Bad Schwalbach im Taunus (events in Andernach are also considered) and in Bavaria at Hochstaufen near Bad Reichenhall . In the latter area, it has been shown that swarms of earthquakes occur after heavy rain .

Web links

Individual evidence

  1. quake swarms in the area of Novy Kostel (Czech Republic) , umwelt.sachsen.de, Retrieved on June 3rd, 2014
  2. Strongest earthquake since 1985 , Mitteldeutsche Zeitung, June 1, 2014.
  3. Swarm quakes in Vogtland! Several earthquakes shake Saxony. In: tag24.de. January 23, 2019, accessed January 27, 2019 .
  4. http://www.echo-online.de/lokales/suedhessen/erdbeben-experten-erkennen-serie_15552693.htm
  5. Homuth: Microseismicity in Hesse - The earthquake series near Bad Schwalbach im Taunus. HLNUG , accessed July 2, 2019 .
  6. Jens Skapski: Small swarm of earthquakes in Andernach. Jens Skapski , accessed October 29, 2019 .
  7. If it rains earthquakes in Bavaria - precipitation can trigger seismic instability , University of Munich, November 2, 2006