Paleoterremotos del Pleistoceno superior - Holoceno observados en sondeos en el Lago Seewen (N de Suiza): eventos equiparables al destructivo terremoto de Basel (1356)

• A. Becker ^[3] ; M.A. Rodríguez-Pascua ^[1] ; C. Davenport ^[2]
  1. [1] Universidad San Pablo

     Universidad San Pablo

     México

     
  2. [2] University of East Anglia

     University of East Anglia

     Norwich District, Reino Unido

     
  3. [3] Institut für Geophysik

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• Localización: Geotemas (Madrid), ISSN 1576-5172, Nº. 6, 3, 2004 (Ejemplar dedicado a: IV Congreso Geológico de España (Zaragoza, 12-15 julio, 2004)), págs. 139-143
• Idioma: español
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• Resumen

  • Former Lake Seewen is located in the Canton of Solothurn, northern Switzerland, which was originated by the Fulnau landslide. The rock masses slid into a river gorge and blocked the flow of the river Seebach about 12,500 y BP which is suitable for paleoseismic research. Four catastrophic events were identified in the sediments which can be correlated among 5 drill sites by different techniques (sedimentology, radiocarbon dates, magnetic susceptibility, palynostratigraphy, micropaleontology; X-ray imaging, paleoseismology), two earthquakes and two floods. The paleo-earthquakes caused seismic liquefaction processes in the sediments: sand-dykes, mushroom structures, collapse structures and disrupted layers; ever with magnitudes greater than 5.5. The ages (2s) in calendar years before Christ (BC) for the earthquakes are 10,350 - 9,750 BC and 4,160 - 3,820 BC, for the floods 5,870 - 5,650 BC and 5,210 - 4,930 BC. Although only two earthquake events could be detected in the sediments of Lake Seewen, it is an important contribution to the record of strong earthquakes in Central Europe, a region which is generally characterized by a low level of seismic activity and for which the historical seismic record does not include many earthquake shocks with magnitudes M > 5.5.