"water infiltration following heavy rains and the heavy roof added during the postwar restoration were to blame."
It's funny (?) how these little details are quietly etched in one or two sentences in small places in articles, as if the theme of massive changes in water activity on the earth weren't all somehow obviously and importantly related.
http://news.yahoo.com/s/ap/20101107/ap_on_sc/eu_italy_pompeii