Becky is correct in saying that the Post Office's insurance covers earthquakes and landslides. You can download a copy of their policy in Acrobat format here;
http://www.poste.it/bancoposta/poste...teassicura.pdf
The relevant part is on page 7...
6) terremoti, valanghe, slavine, inondazioni, alluvioni
ed allagamenti in genere;
which translates as....
6) earthquakes, mudslides, avalanches, and floods.
Copeland Insurance also offer a European policy covering earthquakes, subsidence etc.
Copeland Insurance
230-234 Portland Road
London
SE25 4SL
Tel: 020-8656-8435
Fax: 020-8655-1271
You can read a copy by opening the attachment here....