Advances in Geosciences
www.adv-geosci.net
1680-7340
1680-7359
14
2nd EGU Alexander von Humboldt Conference "The role of Geophysics in Natural Disaster Prevention"
2008
10.5194/adgeo-14-29-2008
http://www.adv-geosci.net/14/29/2008/
http://www.adv-geosci.net/14/29/2008/adgeo-14-29-2008.html
http://www.adv-geosci.net/14/29/2008/adgeo-14-29-2008.pdf
29
33
2008-01-02
Hazards of volcanic lakes: analysis of Lakes Quilotoa and Cuicocha, Ecuador
G. Gunkel
guenter.gunkel@tu-berlin.de
C. Beulker
B. Grupe
F. Viteri
Berlin University of Technology, Dept. of Water Quality Control, Germany
Berlin University of Technology, Dept. of Water, Environment and Marine Science and Technology (VWS), Germany
Universidad Central, Facultad de Geología Minas, Petroleo and Medio Ambiente, Quito, Ecuador
Volcanic lakes within calderas should be viewed as high-risk systems, and an
intensive lake monitoring must be carried out to evaluate the hazard of
potential limnic or phreatic-magmatic eruptions. In Ecuador, two caldera
lakes – Lakes Quilotoa and Cuicocha, located in the high Andean region
>3000 a.s.l. – have been the focus of these investigations. Both volcanoes
are geologically young or historically active, and have formed large and
deep calderas with lakes of 2 to 3 km in diameter, and 248 and 148 m in
depth, respectively. In both lakes, visible gas emissions of CO<sub>2</sub> occur,
and an accumulation of CO<sub>2</sub> in the deep water body must be taken into
account.
<br><br>
Investigations were carried out to evaluate the hazards of these volcanic
lakes, and in Lake Cuicocha intensive monitoring was carried out for the
evaluation of possible renewed volcanic activities. At Lake Quilotoa, a
limnic eruption and diffuse CO<sub>2</sub> degassing at the lake surface are to be
expected, while at Lake Cuicocha, an increased risk of a phreatic-magmatic
eruption exists.
Aguilera, E., Chiodini, G., Cioni, R., Guidi, M., Marini, L., and Raco, B.: Water chemistry of lake Quilotoa (Ecuador) and assessment of natural hazards, J. Volcanol. Geoth. Res., 97, 271–285, 2000.
Barclay, J., Johnstone, J. E., and Matthews, A. J.: Meteorological monitoring of an active volcano: Implications for eruption prediction, J. Volcanol. Geoth. Res., 150, 339–358, 2006.
Christenson, B. W.: Convection and stratification in Ruapehu Crater Lake, New Zealand: Implicaations for Lake Nyos-type gas release eruptions, Geochem. J., 28, 185–197, 1994.
Colt, J.: Computation of dissolved gas concentrations in water as functions of temperature, salinity, and pressure, American Fisheries Society, Special Publication 14, 155 pp., 1984.
Cotel, A. J.: A trigger mechanism for the Lake Nyos disaster, J. Volcanol. Geoth. Res., 88, 343–347, 1999.
Gunkel, G. and Casallas, J.: Limnology of an equatorial high mountain lake – Lago San Pablo, Ecuador: The significance of deep diurnal mixing for lake productivity, Limnologica, 32, 33–43, 2002.
Hansell, A. L., Horwell, C. J., and Oppenheimer, C.: The health hazards of volcanoes and geothermal areas, Occup. Environ. Med. 63, 149–156, 2006.
Imberger, J.: The diurnal mixed layer, Limnol. Oceanogr., 30, 737–770, 1985.
Le Guern, F. and Sigvaldason, G. E.: The Lake Nyos event and natural CO<sub>2</sub> degasing I, Special issues, J. Volcanol. Geoth. Res., 39, 2–3, 1989.
Le Guern, F. and Sigvaldason, G. E.: The Lake Nyos event and natural CO<sub>2</sub> degasing II, Special issues, J. Volcanol. Geoth. Res., 42, 4, 1990.
Martini, M., Giannini, L., Prati, F., Tassi, F., Capaccioni, B., and Ioizzelli P.: Chemical characters of crater lakes in the Azores and Italy: the anomaly of Lake Albano, Geochem. J., 28, 173–184, 1994.
Mastin, L. G. and Witter, J. B.: The hazards of eruptions through lakes and seawater, J. Volcanol. Geoth. Res., 97, 195–214, 2000.
Matthews, A. J., Barclay, J., Carn, S., Thompson, G., and Alexander, J.: Rainfall-induced volcanic activity on Montserrat, Geophys. Res. Lett., 29, 13, 22-1–22-4, 2002.
Mothes, P. and Hall, M. L.: El paisaje interandino y su formación por eventos volcanicos de gran magnitude, Estudios de Geografía 4, 19–38, 1991.
Mothes, P. and Hall, M. L.: Quilotoa's 800 y BP Ash: A valuable stratigraphic marker unit for the integration period, in: Actividad Volcánica y pueblos precolombinos en el Ecuador, edited by: Mothes, P., Abya-Yala, Quito, 111–138, 1998.
Simkin, T. and Siebert, L.: Volcanoes of the world, Geoscience Press, Tuscon, AZ, 349 pp., 1994.
von Hillebrandt, C. and Hall, M. L.: Mapa de los Peligros Volcánoicos Potenciales Asociados con el Volcán Cuicocha, Esc. 1:50.000, Escuela Politécnica Nacional, Quito, Instituto Geográfico Militar, 1988.