```    1/*
2This program is inspired by the morphological characteristics of the Stromboli
3Italian island.
4The Stromboli island is located at the intersection of two geological faults,
5one in the southwest-northeast direction, the other in the east-west direction,
6and contains one of the three volcanoes that are active in Italy.
7This program models the possibility that an eruption or an earthquake occurs at Stromboli.
8
9From
10Elena Bellodi and Fabrizio Riguzzi. Structure learning of probabilistic logic
11programs by searching the clause space. Theory and Practice of Logic
12Programming, FirstView Articles, 2014
13*/
14:- use_module(library(pita)).   15
16:- if(current_predicate(use_rendering/1)).   17:- use_rendering(c3).   18:- endif.   19
20:- pita.   21
24eruption : 0.6 ; earthquake : 0.3 :-
25  sudden_energy_release,
26  fault_rupture(_).
27% If there is a sudden energy release under the island and there is a fault
28% rupture, then there can be an eruption of the volcano on the island with
29% probability 0.6 or an earthquake in the area with probability 0.3
30
31sudden_energy_release : 0.7.
32% The energy release occurs with probability 0.7
33
34fault_rupture(southwest_northeast).
35fault_rupture(east_west).
36% we are sure that ruptures occur in both faults
37
?- `prob(eruption,Prob)`. % what is the probability of an eruption? % expected result 0.588 ?- `prob(earthquake,Prob)`. % what is the probability of an earthquake? % expected result 0.357 ?- `prob(eruption,Prob)`,`bar(Prob,C)`. % what is the probability of an eruption? % expected result 0.588 ?- `prob(earthquake,Prob)`,`bar(Prob,C)`. % what is the probability of an earthquake? % expected result 0.357