Bulletin of Volcanology

, Volume 74, Issue 6, pp 1509–1519

Fumarole/plume and diffuse CO2 emission from Sierra Negra caldera, Galapagos archipelago

  • Eleazar Padrón
  • Pedro A. Hernández
  • Nemesio M. Pérez
  • Theofilos Toulkeridis
  • Gladys Melián
  • José Barrancos
  • Giorgio Virgili
  • Hirochika Sumino
  • Kenji Notsu
Research Article

DOI: 10.1007/s00445-012-0610-4

Cite this article as:
Padrón, E., Hernández, P.A., Pérez, N.M. et al. Bull Volcanol (2012) 74: 1509. doi:10.1007/s00445-012-0610-4

Abstract

Measurements of visible and diffuse gas emission were conducted in 2006 at the summit of Sierra Negra volcano, Galapagos, with the aim to better characterize degassing after the 2005 eruption. A total SO2 emission of 11 ± 2 t day−1 was derived from miniature differential optical absorption spectrometer (mini-DOAS) ground-based measurements of the plume emanating from the Mini Azufral fumarolic area, the most important site of visible degassing at Sierra Negra volcano. Using a portable multigas system, the H2S/SO2, CO2/SO2, and H2O/SO2 molar ratios in the Mina Azufral plume emissions were found to be 0.41, 52.2, and 867.9, respectively. The corresponding H2O, CO2, and H2S emission rates were 562, 394, and 3 t day−1, respectively. The total output of diffuse CO2 emissions from the summit of Sierra Negra volcano was 990 ± 85 t day−1, with 605 t day−1 being released by a deep source. The diffuse-to-plume CO2 emission ratio was about 1.5. Mina Azufral fumaroles released gasses containing 73.6 mol% of H2O; the main noncondensable components amounted to 97.4 mol% CO2, 1.5 mol% SO2, 0.6 mol% H2S, and 0.35 mol% N2. The higher H2S/SO2 ratio values found in 2006 as compared to those reported before the 2005 eruption reveal a significant hydrothermal contribution to the fumarolic emissions. 3He/4He ratios measured at Mina Azufral fumarolic discharges showed values of 17.88 ± 0.25 RA, indicating a mid-ocean ridge basalts (MORB) and a Galapagos plume contribution of 53 and 47 %, respectively.

Keywords

Sierra Negra volcano Galapagos Carbon dioxide Diffuse emission Volcanic activity Sulfur dioxide Volcanic gasses 

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Eleazar Padrón
    • 1
    • 2
  • Pedro A. Hernández
    • 1
    • 2
  • Nemesio M. Pérez
    • 1
    • 2
  • Theofilos Toulkeridis
    • 3
  • Gladys Melián
    • 1
    • 2
  • José Barrancos
    • 1
    • 2
  • Giorgio Virgili
    • 4
  • Hirochika Sumino
    • 5
  • Kenji Notsu
    • 5
  1. 1.Environmental Research DivisionInstituto Tecnológico y de Energías Renovables (ITER)S/C de TenerifeSpain
  2. 2.Instituto Volcanológico de Canarias (INVOLCAN)TenerifeSpain
  3. 3.Escuela Politécnica del EjércitoSangolquí-QuitoEcuador
  4. 4.WEST SystemsPontederaItaly
  5. 5.Geochemical Research Center, Graduate School of ScienceThe University of TokyoTokyoJapan

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