A magmatic source for fumaroles and diffuse degassing from the summit crater of Teide Volcano (Tenerife, Canary Islands): a geochemical evidence for the 2004-2005 seismic-volcanic crisis.

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Title:	A magmatic source for fumaroles and diffuse degassing from the summit crater of Teide Volcano (Tenerife, Canary Islands): a geochemical evidence for the 2004-2005 seismic-volcanic crisis.
Authors:	Melián, G. gladys@iter.es, Tassi, F., Pérez, N., Hernández, P., Sortino, F.¹, Vaselli, O., Padrón, E., Nolasco, D., Barrancos, J., Padilla, G., Rodríguez, F., Dionis, S., Calvo, D., Notsu, K.², Sumino, H.²
Source:	Bulletin of Volcanology. Aug2012, Vol. 74 Issue 6, p1465-1483. 19p.
Subject Terms:	Volcanoes, Geochemical modeling, Volcanic gases, Carbon dioxide
Geographic Terms:	Tenerife (Canary Islands), Canary Islands
Abstract:	The present work reports the results of 15 studies of diffuse CO degassing performed at Teide Volcano crater (Canary Island, Spain) and the chemical and isotopic compositions of fluids discharged from a fumarolic field located at the top of the volcano as measured between 1991 and 2010. A higher contribution of magmatic gases accompanied by enhanced total diffuse CO emissions were observed in relation with a seismic crisis that occurred in Tenerife Island between 2001 and 2005, with the main peak of seismic activity between April and June 2004. A significant pulse in total diffuse CO emission was observed at the crater of Teide (up to 26.3 t day) in 2001. In December 2003, the chemical composition of the Teide fumarole changed significantly, including the appearance of SO, an increase in the HCl and CO concentrations and in the CH/CH and CH/CH ratios, and a decrease in the HS, CH, and CH concentrations and in the gas/steam ratio. A few months after a drastic decrease in seismic activity, the SO, HCl, and CO concentrations and the CH/CH and CH/CH ratios strongly decreased, whereas the CH and CH concentrations and the gas/steam ratios increased. According to the trends shown by both the geochemical parameters and the seismic signals late in the observation period, the risk of a rejuvenation of volcanic activity at Teide is considered to be low. The associated temporal changes in seismic activity and magmatic degassing indicate that geophysical and fluid geochemistry signals in this system are related. Future monitoring programs aimed at mitigating volcanic hazard on Tenerife Island should involve coupled geophysical and geochemical studies. [ABSTRACT FROM AUTHOR]
Database:	Energy & Power Source

Description
Abstract:	The present work reports the results of 15 studies of diffuse CO degassing performed at Teide Volcano crater (Canary Island, Spain) and the chemical and isotopic compositions of fluids discharged from a fumarolic field located at the top of the volcano as measured between 1991 and 2010. A higher contribution of magmatic gases accompanied by enhanced total diffuse CO emissions were observed in relation with a seismic crisis that occurred in Tenerife Island between 2001 and 2005, with the main peak of seismic activity between April and June 2004. A significant pulse in total diffuse CO emission was observed at the crater of Teide (up to 26.3 t day) in 2001. In December 2003, the chemical composition of the Teide fumarole changed significantly, including the appearance of SO, an increase in the HCl and CO concentrations and in the CH/CH and CH/CH ratios, and a decrease in the HS, CH, and CH concentrations and in the gas/steam ratio. A few months after a drastic decrease in seismic activity, the SO, HCl, and CO concentrations and the CH/CH and CH/CH ratios strongly decreased, whereas the CH and CH concentrations and the gas/steam ratios increased. According to the trends shown by both the geochemical parameters and the seismic signals late in the observation period, the risk of a rejuvenation of volcanic activity at Teide is considered to be low. The associated temporal changes in seismic activity and magmatic degassing indicate that geophysical and fluid geochemistry signals in this system are related. Future monitoring programs aimed at mitigating volcanic hazard on Tenerife Island should involve coupled geophysical and geochemical studies. [ABSTRACT FROM AUTHOR]
ISSN:	02588900
DOI:	10.1007/s00445-012-0613-1