Review on the use of natural cave speleothems as palaeoseismic or neotectonics indicators

Collapses that affect cave speleothems have frequently been attributed to earthquakes, although this has not been proved. Observations after an earthquake and laboratory tests indicate that only slender speleothems break under coseismic solicitation. Other causes as subsidence, decompression and creeping of ice or cave sediments explain most of the breaks. Tectonics is also a major cause of speleothems breakages and it is possible to detect minute movements of faults. It seems possible to make the difference between brutal coseismic movements and aseismic slow ones. However, the interpretation is often difficult, as the damage can also be caused by gravity tectonics or glacitectonics.Original Abstract: Les chutes de concretions des grottes ont souvent ete attribuees a des tremblements de terre, sans qu'aucune preuve ne soit apportee. Les observations effectuees consecutivement aux seismes et les essais en laboratoire montrent que les degats cosismiques se resument au bris de tres fines concretions. D'autres causes, comme la subsidence, la decompression, le fluage de glace ou de sediments, expliquent la majorite des ruptures observees. La tectonique active est aussi une cause importante de rupture de concretions, et meme de tres faibles mouvements de failles peuvent etre mis en evidence. Il semble parfois possible de differencier des mouvements rapides, qui pourraient etre cosismiques, de mouvements lents asismiques. Cependant, leur interpretation est souvent difficile, car ces phenomenes peuvent aussi etre gravitaires ou glaciotectoniques.