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| Titel |
Geochemical monitoring of Taal volcano (Philippines) by means of diffuse CO2 degassing studies |
| VerfasserIn |
Eleazar Padrón, Pedro A. Hernández, Carlo Arcilla, Nemesio M. Pérez, Alfredo M. Lagmay, Fátima Rodriguez, Gerald Quina, Mar Alonso, Germán D. Padilla, Mario A. Aurelio |
| 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 |
250146225
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| Publikation (Nr.) |
 EGU/EGU2017-10236.pdf |
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| Zusammenfassung |
| Observing changes in the discharge rate of CO2 is an important part of volcanic monitoring
programs, because it is released by progressive depressurization of magma during ascent and
reach the surface well before their parental magma. Taal Volcano in Southwest Luzon,
Philippines, lies between a volcanic arc front facing the subduction zone along the
Manila Trench and a volcanic field formed from extension beyond the arc front. Taal
Volcano Island is formed by a main tuff cone surrounded by several smaller tuff cones,
tuff rings and scoria cones. This island is located in the center of the 30 km wide
Taal Caldera, now filled by Taal Lake. To monitor the volcanic activity of Taal
volcano is a priority task in the Philippines, because several million people live
within a 20-km radius of Taal’s caldera rim. During the last period of volcanic
unrest from 2010 to 2011, the main crater lake of Taal volcano released the highest
diffuse CO2 emission rates through the water surface reported to date by volcanic
lakes worldwide. The maximum CO2 emission rate measured in the study period
occurred two months before the strongest seismic activity recorded during the unrest
period (Arpa et al., 2013, Bull Volcanol 75:747). After the unrest period, diffuse
CO2 emission has remained in the range 532-860 t/d in the period 2013-2016. In
January 2016, an automatic geochemical station to monitor in a continuous mode the
diffuse CO2 degassing in a selected location of Taal, was installed in January 2016 to
improve the early warning system at the volcano. The station is located at Daang
Kastila, at the northern portion of the main crater rim. It measures hourly the diffuse
CO2 efflux, atmospheric CO2 concentration, soil water content and temperature,
wind speed and direction, air temperature and humidity, rainfall, and barometric
pressure. The 2016 time series show CO2 efflux values in the range 20-690 g m−2
d−1.Soil temperature, heavily influenced by rainfall, ranged between 74 and 96oC.
Although short-temp fluctuations in the diffuse CO2 emission time series at Daang
Kastila were partially driven by meteorological parameters, the main CO2 efflux
changes were not driven by fluctuations of meteorological variables such as wind
speed or barometric pressure and seem clearly to be associated with fluid pressure
fluctuations in the volcanic system. These results showed the potential of applying
continuous and discrete monitoring of soil CO2 efflux to improve and optimize
the detection of early warning signals of future volcanic unrest at Taal volcano. |
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