WORKING GROUP 9 
MARCHESINI, PISTOLESI, BOLOGNINI 
525 
Fig. 1. Regional gravity (Bouguer Anomaly according to G. Salvini 1954), and Post-Pliocene 
uplift (top of Pliocene according to Sestini 1932). Steam-producing areas shaded. 
The purpose of this study is two-fold: 1. To investigate the relationship be 
tween the faults and fractures observed on the airphotographs and the geol 
ogical and production pictures of the field. 2. To evaluate the convenience of 
extending photo interpretation to new areas. 
The steam-field 
The steam-producing area consists of six separate production centers, 
now covering a total surface of approximately 40 square km. Exploration drill