VOLUME 1- 1991

Contents
To the readers
VII
M. Dragoni, S. Pondrelli: Lava flow dynamics with vertical temperature variation
1
M. Martini, L. Giannini, B. Capaccioni: Geochemical and seismic precursors of volcanic activity
7
M. Martini, L. Giannini, B. Capaccioni: The influence of water on chemical changes of fumarolic gases: different characters and their implications in forecasting volcanic activity
13
M. Neri, V. H. Garduno, G. Pasquarè, R. Rasà: Studio strutturale e modello cinematico della Valle del Bove e del settore nord-orientale etneo
17
R. Cristofolini, R. A. Corsaro, C. Ferlito: Variazioni petrochimiche nella successione etnea: un riesame in base a nuovi dati da campioni di superficie e da sondaggi
25
G. Distefano, S. Gresta: Energy releases at Etna volcano during 1983-1987
39
A. Montalto, G. Distefano, G. Patanè: Sismicità e dinamica dei fluidi magmatici al vulcano Etna
43
G. Patanè, S. Imposa, S. Menza, G. Distefano, G. Lombardo: Considerations on Etna´s low-energy seismic and volcanic activity in 1990
49
E. Cubellis, C. Del Gaudio, M. Ferri, M. Grimaldi, F. Obrizzo, C. Ricco, G. Luongo: Gravity anomalies in the Campanian Plain (Southern Italy) and their volcano-tectonic implications
57
M. D´Orazio, M. A. Laurenzi 1. M. Villa: 40Ar/39Ar dating of a shoshonitic lava flow of the Radicofani volcanic center (Southern Tuscany)
63
B. Capaccioni, S. Coniglio, F. Fratini: Clay minerals on recent products of hydromagmatic activity: considerations on their genesis
69
G. Gasparotto, E. Lanti, G. Lanzafame, P. L. Rossi, C. A. Tranne: La palagonitizzazione quale processo di trasformazione idrotermale: le piroclastiti di Cala Pozzolana di Ponente dell´isola di Linosa (Canale di Sicilia)
79
F. Sortino, S. Inguaggiato, S. Francofonte: Determination of HF, HCI, and total sulphur in fumarolic fluids by ion chromatography
89
Collected papers on unrest at Vulcano
 
F. Barberi, G. Neri, M. Valenza, L. Villari: 1987-1990 unrest at Vulcano
95
G. Frazzetta, L. La Volpe: Volcanic history and maximum expected eruption at "La Fossa di Vulcano" (Aeolian Islands, Italy)
107
A. Gioncada, A. Sbrana: "La Fossa caldera", Vulcano: inferences from deep drillings
115
R. Rasà, L. Villari: Geomorphological and morpho-structural investigations on the Fossa Cone (Vulcano, Aeolian Islands): a first outline
127
G. Gabbianelli, C. Romagnoli, P. L. Rossi, N. Calanchi, F. Lucchini: Submarine morphology and tectonics of Vulcano (Aeolian Islands, Southeastern Tyrrhenian Sea) 
135
F. Ferrucci, G. Gaudiosi, G. Milano, A. Nercessian, G. Vilardo, G. Luongo: Seismological exploration of Vulcano (Aeolian Islands, southern Tyrrhenian Sea): case history 
143
G. Falzone, B. Puglisi, R. Velardita: Ground deformation studies in the Lipari-Vulcano eruptive complex (Aeolian Islands): notes and comments on the most significant observations during the period 1975-1988, with particular reference to the Summer 1988 Special Surveillance Plan
153
G. Neri, A. Montalto, D. Patanè, E. Privitera: Earthquake space-time-magnitude patterns at Aeolian Islands (Southern Italy) and implications for the volcanic surveillance of Vulcano Contents 
163
G. Vilardo, M. Castellano, G. Gaudiosi, F. Ferrucci: Seismic surveillance at Vulcano by use of a portable digital array: features of the seismicity and relocation of the events in a 3-D heterogeneous structure
 171
G. Chiodini, R. Cioni, M. Guidi, L. Marini: Geochemical variations at Fossa Grande crater fumaroles (Vulcano Island, Italy) in summer 1988
179
G. Chiodini, R. Cioni, B. Raco, G. Taddeucci: Gas geobarometry applied to evaluate phreatic explosion hazard at Vulcano Island (Sicily, Italy) 
193
G. Capasso, G. Dongarra, R. Favara, S. Hauser, M. Valenza: Chemical changes in waters from Vulcano Island: an update 
199
M. F. Le Cloarec, E. Corazza, M. Pennisi, G. Lambert: Radioactivity of fumarolic gases at Vulcano (Italy) 
211
G. Magro, M. Pennisi: Light noble gases and nitrogen in the crater fluids at Vulcano (Italy): special survey from June to September 1988 
215
B. Badalamenti, S. Gurrieri, S. Hauser, F. Parello, M. Valenza: Change in the soil CO2 output at Vulcano Island during the summer 1988 
219
B. Badalamenti, G. Chiodini, R. Cioni, R. Favara, S. Francofonte, S. Gurrieri, S. Hauser, S. Inguaggiato, F. Italiano, G. Magro, P. M. Nuccio, F. Parello, M. Pennisi, L. Romeo, M. Russo, F. Sortino, M. Valenza, F. Vurro: Special field workshop at Vulcano (Aeolian Islands) during summer 1988: geochemical results 
223
R. Bargagli, C. Barghigiani: Preliminary report on Hg distribution at Vulcano Island in relation to the volcanic activity 
229
M. Brondi, M. Dall´Aglio: Evolution of mercury, arsenic, antimony, radon and helium contents in ground waters and fumaroles since 1983 through 1989 at Vulcano Island (Southern Italy)
233
F. Italiano, P. M. Nuccio: Preliminary investigations on the underwater gaseous manifestations of Vulcano and Lipari 
243
F. Italiano, P. M. Nuccio, G. Pecoraino, M. Valenza: Monitoring of acid gases at the crater of Vulcano using the method of the alkaline traps 
249
Data related to eruptive activity, unrest phenomena and other observations on the italian active volcanoes l990
255
ETNA
 
S. Calvari, M. Coltelli, M. Pompilio, V. Scribano: The eruptive activity between October 1989 and December 1990 
257
E. Privitera, C. Cardaci, D. Patane, S. Spampinato: Seismic activity 
260
A. Bonaccorso, O. Campisi, G. Falzone, B. Puglisi, R. Velardita, L. Villari: Ground deformation: electroptical distance measurementes and ground tilt 
265
G. Nunnari, G. Puglisi: GPS survey
268
STROMBOLI
 
S. Falsaperla: Stromboli 
272
VULCANO
 
G. Budetta, T. Caltabiano, C. Del Negro, F. Ferrucci: A permanent array for magnetic observation at Vulcano 
275