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| Titel |
Diffuse CO2 degassing monitoring of Cerro Negro volcano, Nicaragua |
| VerfasserIn |
Pedro A. Hernández, Mar Alonso, Martha Ibarra, Wesly Rodríguez, Gladys V. Melián, Armando Saballos, José Barrancos, Nemesio M. Pérez, Julio Álvarez, William Martínez |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250146316
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| Publikation (Nr.) |
 EGU/EGU2017-10336.pdf |
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| Zusammenfassung |
| We report the results of fourteen soil CO2 efflux surveys by the closed accumulation chamber
method at Cerro Negro volcano, Nicaragua. The surveys were undertaken from 1999 to 2016
to constrain the diffuse CO2 emission from this volcano and to evaluate the spatial and
temporal variations of CO2 degassing rate in relation to the eruptive cycle. Cerro Negro is an
active basaltic volcano belonging to the active Central American Volcanic Arc which includes
a 1,100 Km long chain of 41 active volcanoes from Guatemala to Panama. Cerro Negro first
erupted in 1850 and has experienced 21 eruptive eruptions with inter eruptive average
periods between 7 and 9 years. Since the last eruption occurred on 5 August 1999,
with erupted lava flows and ash clouds together with gas emissions, a collaborative
research program between INETER and ITER/INVOLCAN has been established for
monitoring diffuse CO2 emissions from this volcano. The first survey carried out at Cerro
Negro was in December 1999, just 3 months after the 1999 eruption, with a total
diffuse CO2 emission output estimated on 1,869 ± 197 td−1. The second survey
carried out in March 2003, three years after the eruption, yielded a value of 432 ±
54 td−1. Both values that can be considered within the post-eruptive phase. The
last survey performed at Cerro Negro was in November 2016, with an estimated
diffuse CO2 emission of 63 ± 14 t⋅d−1and soil CO2 efflux values ranging from
non-detectable (∼0.5 g m−2 d−1) up to 7264 g m−2 d−1. The long-term record of
diffuse CO2 emissions at Cerro Negro shows small temporal variations in CO2
emissions with a peak in 2004 (256 ± 26 td−1) followed by a peak in seismicity. Except
this value, the rest of estimated values can be considered within the inter-eruptive
phase, period during which a decreasing trend on the total diffuse CO2 output has
been observed, with estimates between 10 and 83 t⋅d−1. Regarding to the spatial
distribution of diffuse CO2 values, most of relatively high CO2 efflux values were
measured along the 1995 and 1999 craters together with higher soil H2S efflux and soil
temperatures, and always close to the fumarolic areas, suggesting a structural control of
the degassing process. The observed relationship between the long-term record of
diffuse CO2 emissions and volcanic-seismic activity indicates that monitoring CO2
emission is an important geochemical tool for the volcanic surveillance at Cerro Negro. |
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