Co-seismic ruptures and deformations recorded by speleothems in the epicentral zone of the Basel earthquake |
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| Authors: | Francis Lemeille Marc Cushing David Carbon Bertrand Grellet Thomas Bitterli Christine Flehoc |
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| Institution: | 1. IPSN CEA, BP 6, 92265 Fontenay-aux-Roses cedex, France;2. edward.cushing@ipsn.fr;3. francis.lemeille@ipsn.fr;4. GEO-TER, p?le géoenvironnement, 3, rue Jean-Monnet, 34830 Clapiers, France;5. geoter@mnet.fr;6. Deceased on October 25 1998 during a speleogical expedition in the Bernese Oberland Institut suisse de spéléologie et karstologie (ISSKA) Société suisse de spéléologie;7. BRGM, BP 6009, 45060 Orléans cedex 2, France;8. flehoc@smn.brgm.fr;9. innocent@smn.brgm.fr |
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| Abstract: | AbstractThe study of growth anomalies of speleothems in a karstic environment can provide potential evidence or palaeoearthquakes. These data are used to study the recurrence times of major earthquakes in areas where evidence for historic seismicity is lacking. A study has been carried out in the epicentral area of the 1356 Basel earthquake (epicentral intensity = VII-VIII, macroseismic magnitude = 6.2). The Bättlerloch and Dieboldslöchli caves, situated in the area of greatest damage, show growth anomalies of speleothems possibly related to a seismic event (several breaks of speleothems an offsets of the axis of the regrowths). The first U/Th disequilibrum measurements by alpha spectrometry show recent ages (less than several tens of thousands of years and pro a y historic). 14C dating by AMS of carbonate laminations taken on both sides of the anomalies confirm the evidence of a seismic event around 1300 AD. More accurate datings by U/Th TIMS are carried out in order to compare the information provided by the two different dating methods. © Elsevier, Paris |
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| Keywords: | Basel Jura karst speleothems earthquake |
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