1356 Basel earthquake

1356 Basel earthquake
Date October 18, 1356 (1356-10-18)
Magnitude 6.2-6.5 Mw
Countries or regions  Switzerland, Basel
Casualties 1,000

The Basel earthquake of 18 October 1356 is the most significant seismological event to have occurred in Central Europe in recorded history[1] and may have had a Mw magnitude as strong as 7.1.[2]

The earthquake destroyed the town of Basel, Switzerland, sited near the southern end of the Upper Rhine Graben, and caused much destruction in a vast region extending into France and Germany. Though major earthquakes are common at the seismically active edges of tectonic plates in Turkey, Greece and Italy, intraplate earthquakes are rare events in Central Europe: according to the Swiss Seismological Service, of more than 10,000 earthquakes in Switzerland over the past 800 years, only half a dozen of them have registered more than 6.0 on the Richter scale.[3]

The epicentre was in Germany, in the Upper Rhine valley (Rhine rift) between Waldkirch and St. Peter in Breisgau-Hochschwarzwald.

The earthquake could be felt as far away as Zürich, Konstanz and even in Île-de-France. The maximum seismic intensity registered on the MSK scale was of IX–X. Notably, the macroseismic map was established on the basis of damages reported by the region's 30 to 40 castles.[4][5]

From this macroseismic data, various studies have been conducted to estimate the Mw magnitude of the earthquake, which have resulted in various values of 6.2 (BRGM 1998)[5][2]; 6.0 (GEO-TER 2002)[2]; 6.9 (SED 2004) with a follow-up report suggesting a range of between 6.7 to 7.1[2]; 6.6 (GFZ 2006)[2]; and a major Swiss study by 21 European experts, with American involvement, in which four sub-groups estimated values of 6.9, 6.9, 6.5 to 6.9, and 6.5 ± 0.5 (PEGASOS 2002 - 2004)[2]. There are also different opinions about which faults were involved.[2]

After a precursor tremblor between 19:00 and 20:00 local time, the main earthquake struck in the evening at around 22:00, and numerous aftershocks followed during the night between October 18–19.[6] Basel experienced a second, very violent shock in the middle of the night. The town within the ramparts was destroyed by a fire when torches and candles falling to the floor set the wooden houses ablaze. The number of deaths within the town of Basel alone is estimated at 300. All major churches and castles within a 30 km radius of Basel were destroyed.[5]

The seismic crisis lasted a year. The modeling of the macroseismic data[5] suggests that the earthquake's source had an East-West orientation, a direction corresponding with the overlapping faults on the Jura Front.[7] On the other hand, recent paleoseismologic studies attribute instead the cause of this earthquake to a normal fault, oriented NNE-SSW and south of the town.[8] The significant magnitude of the event suggests a possible extension of this fault under the town itself.

This earthquake is also known as the 'Séisme de la Saint-Luc', as 18 October is the feast day of Saint Luke the Evangelist.

See also

References

  1. ^ "The most damaging intra-plate earthquake known to have occurred in central Europe", according to (Risk Management Solutions) 1356 Basel Earthquake: 650-year Retrospective, 2006.
  2. ^ a b c d e f g Centrale Nucléaire de Fessenheim : appréciation du risque sismique RÉSONANCE Ingénieurs-Conseils SA, published 2007-09-05, accessed 2011-03-30
  3. ^ "Switzerland prepares for seismic calamity" 18 October 2006; the canton of Valais in southern Switzerland experienced notable earthquakes in 1855 and 1946 (Risk Management Solutions 2006)
  4. ^ D. Mayer-Rosa and B. Cadiot (1979). "A review of the 1356 Basel earthquake: basic data", Tectonophysics, 53, pp. 325–333.
  5. ^ a b c d Lambert J., Winter T., Dewez T. J. B. et P. Sabourault (2005). "New hypotheses on the maximum damage area of the 1356 Basel earthquake (Switzerland)", Quaternary Science Reviews, 24, pp. 383–401.[1]PDF (1.26 MiB) [2]
  6. ^ Von Waltenkofen K. (1357). Alphabetum Narrationum.
  7. ^ Meyer, B., Lacassin, R., Brulhet, J., Mouroux, B., 1994. "The Basel 1356 earthquake: which fault produced it?" Terra Nova 6, 54–63.
  8. ^ Meghraoui M., Delouis B., Ferry M., Giardini D., Huggenberger P., Spottke I. et M. Granet (2001). "Active Normal Faulting in the Upper Rhine Graben and Paleoseismic Identification of the 1356 Basel Earthquake" Science, 293, pp. 2070–73. doi: 10.1126/science.1010618
This article incorporates information from this version of the equivalent article on the French Wikipedia.

External links