ORIGINAL ARTICLE Evaporite karst and sinkholes: a synthesis on the case of Camaiore (Italy) V. Buchignani Æ G. D’Amato Avanzi Æ R. Giannecchini Æ A. Puccinelli Received: 1 June 2006 / Accepted: 6 March 2007 / Published online: 15 May 2007 Ó Springer-Verlag 2007 Abstract In 1995 a sinkhole suddenly formed at Camaiore (Tuscany, Italy), causing destruction or heavy damages to several houses and resulting in the evacuation of many people. To understand the causes, for the formation and evolution of the collapse, surface and underground geo- logic features were investigated and reconstructed on the basis of geologic and geognostic surveys. The sinkhole area is underlain by thick alluvial deposits that cover a bedrock consisting of the Calcare cavernoso formation. This formation results from hydration and dissolution of Triassic evaporites and has a characteristic spongy and vacuolate texture. The bedrock contains karst cavities, generally filled by breccia and/or alluvial materials. Thus, the sinkhole disaster could be ascribed to deep collapse of a cave in the bedrock, and might be considered a distant effect of ancient karst phenomena in evaporites. Keywords Evaporite Á Karst Á Sinkhole Á Italy Introduction Sinkholes are particularly common in karst areas and are among the most frequent and fearful natural catastrophes in the USA, especially in Florida (Beck 1984). It is also difficult to develop effective countermeasures for such phenomena, whose forecasting is still very problematic (Sinclair and Stewart 1985; Newton 1987; Wilson and Shock 1996). On 15 October 1995, a sinkhole suddenly formed in Camaiore (northern Tuscany, Italy), causing destruction or heavy damage to several houses (Fig. 1). The collapse occurred 5 days after an M 4.8 earthquake, about 50 km from Camaiore; that seismic event was clearly felt at Camaiore. The sinkhole started in the night, with a progressive funnel-shaped lowering of the ground (about 2 m in the centre). At 7 a.m. the sinkhole opened with a diameter of 15–20 m, and groundwater rising up to 2–3 m below the ground surface. In a few hours, the sinkhole progressively widened to about 30 m, reaching a depth of about 18 m. The water table then stabilized at 4–5 m below the surface. According to residents who witnessed the event, prior to the collapse there were ground movements and structural deformations that alerted the population, and they could escape without injury. As an emergency countermeasure, the sinkhole was quickly filled with about 4,500 m 3 of rock fragments, thus stopping the widening process. However, many people had to leave their homes for a long time. Several authors studied this sinkhole event, trying to understand its main features and causes (Buchignani 2002; D’Amato Avanzi et al. 2002, 2004; Buchignani et al. 2004; Di Filippo and Toro 2004). Since geological structure and evolution usually control development of sinkholes, many investigations particularly focused on understanding the geological features of the area. They mainly consisted of geological and geophysical surveys and deep boreholes. This paper aims at explaining and summarizing the main results of several different studies on the surface and underground characteristics of the Camaiore area that led to the development of the sinkhole. V. Buchignani Lucca, Italy G. D’Amato Avanzi Á R. Giannecchini (&) Á A. Puccinelli Dipartimento di Scienze della Terra, Universita ` di Pisa, Via S. Maria, 53, 56126 Pisa, Italy e-mail: rgiannecchini@dst.unipi.it 123 Environ Geol (2008) 53:1037–1044 DOI 10.1007/s00254-007-0730-x