Adventive hydrothermal circulation on Stromboli volcano (Aeolian Islands, Italy) revealed by geophysical and geochemical approaches: Implications for general fluid flow models on volcanoes

• Published in: Journal of volcanology and geothermal research Vol. 196; no. 1; pp. 111 - 119
• Main Authors: Finizola, A., Ricci, T., Deiana, R., Cabusson, S. Barde, Rossi, M., Praticelli, N., Giocoli, A., Romano, G., Delcher, E., Suski, B., Revil, A., Menny, P., Di Gangi, F., Letort, J., Peltier, A., Villasante-Marcos, V., Douillet, G., Avard, G., Lelli, M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 15-09-2010; Elsevier
• Subjects: 2007 Stromboli eruptive crisis; adventive hydrothermal flow; Crystalline rocks; Earth Sciences; Earth, ocean, space; electrical resistivity tomography; Environmental Sciences; Exact sciences and technology; Global Changes; hydrothermal system; Igneous and metamorphic rocks petrology, volcanic processes, magmas; Sciences of the Universe; self-potential; soil diffuse degassing; Stromboli; temperature; Volcanology; Vulcano; Europe; Southern Europe; Aeolian Islands; Tyrrhenian Sea; Sicily Italy; Italy; Marches Italy; Mount Etna; West Mediterranean; Mediterranean Sea; Stromboli; Italy, Sicilia, Lipari Is., Stromboli I., Stromboli Volcano; electrical resistivity tomography; soil diffuse degassing; hydrothermal system; adventive hydrothermal flow; 2007 Stromboli eruptive crisis; temperature; self-potential; Stromboli; fissures; magmatic fluids; degassing; surveys; ERTS; faults; tomography; cones; thermal waters; explosions; soils; flow; electrical resistivity; models; hydrothermal circulation; impact craters; topography; subsurface; ground-penetrating radar; vents; depth; boiling
• ISSN: 0377-0273; 1872-6097
• DOI: 10.1016/j.jvolgeores.2010.07.022

On March 15th 2007 a paroxysmal explosion occurred at the Stromboli volcano. This event generated a large amount of products, mostly lithic blocks, some of which impacted the ground as far as down to 200
m
a.s.l., about 1.5
km far away from the active vents. Two days after the explosion, a new vapour emission was discovered on the north-eastern flank of the volcanic edifice, at 560
m
a.s.l., just above the area called “Nel Cannestrà”. This new vapour emission was due to a block impact. In order to investigate the block impact area to understand the appearance of the vapour emission, we conducted on May 2008 a multidisciplinary study involving Electrical Resistivity Tomography (ERT), Ground Penetrating Radar (GPR), Self-Potential (SP), CO
2 soil diffuse degassing and soil temperature surveys. This complementary data set revealed the presence of an anomalous conductive body, probably related to a shallow hydrothermal level, at about 10–15
m depth, more or less parallel to the topography. It is the first time that such a hydrothermal fluid flow, with a temperature close to the water boiling point (76
°C) has been evidenced at Stromboli at this low elevation on the flank of the edifice. The ERT results suggest a possible link between (1) the main central hydrothermal system of Stromboli, located just above the plumbing system feeding the active vents, with a maximum of subsurface soil temperature close to 90
°C and limited by the NeoStromboli summit crater boundary and (2) the investigated area of Nel Cannestrà, at ~
500
m
a.s.l., a buried eruptive fissure active 9
ka ago. In parallel, SP and CO
2 soil diffuse degassing measurements suggest in this sector at slightly lower elevation from the block impact crater a magmatic and hydrothermal fluid rising system along the N41° regional fault. A complementary ERT profile, on May 2009, carried out from the NeoStromboli crater boundary down to the block impact crater displayed a flank fluid flow apparently connected to a deeper system. The concept of shallow hydrothermal level have been compared to similar ERT results recently obtained on Mount Etna and La Fossa cone of Vulcano. This information needs to be taken into account in general fluid flow models on volcanoes. In particular, peripheral thermal waters (as those bordering the north-eastern coast of Stromboli) could be contaminated by hydrothermal and magmatic fluids coming from regional faults but also from the summit.
►Hydrothermal systems can be evidenced by multidisciplinary approach.►Shallow hydrothermal fluid flow have been evidenced at low elevation.►This shallow fluid flow come from the condensation of the main hydrothermal system.►Shallow hydrothermal fluid flow cloud be evidenced in many volcanoes.