KWI Conduit| Volume VIII, Number 1 |
Spring 2000
|
KWI Conduit| Volume VIII, Number 1 |
Spring 2000
|
On the 31st of March, the City of Grosetto and the Province of Grosetto, in cooperation with the Region of Tuscany, in Italy, sponsored a day-long conference on sinkholes titled “Le Voragini Catastrofiche—Sinkholes: A New Problem for Tuscany.” The conference was held in the Conference Salon of the City of Grosetto and approximately one hundred professionals and government officials were in attendance. Simultaneous translation was provided from Italian to English and from English to Italian.
The conference was prompted by the development of a large new sinkhole last year on agricultural land near Grosetto. The sinkhole which collapsed over a two day time period is approximately 100 meters in diameter. It is now water-filled and relatively shallow, but the underlying limestone is covered by 200 meters of unconsolidated sediment. A similar sinkhole developed in 1995 near Camaiore and destroyed five houses. However, these are the only large, damaging sinkholes to have formed in the Region of Tuscany in recent time.
Dr. Barry F. Beck, of P.E. LaMoreaux & Associates, Inc., Oak Ridge, Tennessee, USA, was the keynote speaker. He summarized the current state-of-knowledge on traditional karstic sinkhole development and its relationship to man’s activities. However, he stressed that these two sinkholes are in unusual geologic settings and may not have formed by the traditional processes. The cover sediment is many times thicker than in most karst areas. Moreover, the area is tectonically active and there are thermal springs. In fact, when the Grosetto sinkhole collapsed, two thermal springs within a few miles of the site produced unusual quantities of mud.
Also speaking were Dr. Paolo Forti (U of Bologna) who spoke on “Hyperkarst evolution in a thermal aquifer,” Dr. Ugo Sauro (U of Padua) on “Some recent collapses in the karst of the Veneteian Fore-Alps,” Luigi Micheli (Regional Geologist for Tuscany) on “Superficial karst in the Calcare Cavernosa in Tuscany,” and Sanja Favre (U of Zagrabe) on “Calculating tectonic strain and stress from sinkhole distribution,” among many others. There were several papers describing the local geology relevant to the sinkhole collapse, including “Hydrogeology and evolution of the Plain of Grosetto” presented by Dr. G. Pranzini of the University of Florence. A proceedings volume of the conference presentations is planned.
At mid-day the participants journeyed to the site of the Grosetto Sinkhole where a luncheon was held. Those who had not yet seen the sinkhole had the opportunity to visit it.
The Region of Tuscany sponsored Dr. Beck’s participation in this conference, and he is very grateful for their support. The Region is now negotiating with P.E. LaMoreaux & Associates, Inc., to direct a multidisciplinary study of the nature of this sinkhole collapse and whether it was triggered by the use of irrigation water in the region or other human influences.
KWI Conduit
(c) 2000 Karst Waters Institute