Over the past decade, remote sensing has been used increasingly in the study of active volcanoes and their associated hazards. Ground‐based remote sensing techniques, such as those aimed at the analysis of volcanic gases or fumarole temperatures, are now part of routine monitoring operations with additional satellite‐based remote sensing methods. It is likely that the use of satellite‐based systems will be most beneficial for volcano monitoring in developing country regions and remote areas. In such situations, an operational real‐time satellite remote sensing system could provide rapid assessment of volcanic activity levels and potentially be used to derive crucial information for disaster prevention. This would allow key at‐risk areas to be rapidly and appropriately targeted. An operational test of such a system has been carried out in the past 3 years in Central America, based on local reception and analysis of Advanced Very High Resolution Radiometer (AVHRR) imagery. Here we analyse the performance and data quality for recent activity of Fuego volcano (Guatemala). We assess the ability of the system to detect, quantify and monitor periods of heightened activity and consider the benefits of such information being available in near‐real time to local geoscientists and for hazard mitigation. We show that the system is able to detect significant changes in volcanic activity (November and December 2004, February and December 2005). There are good comparisons for these events with large‐scale monitoring systems using additional remote sensing data. This paper provides one of the few evaluations of the direct application of operational AVHRR data to volcanic hazard monitoring and disaster management in developing countries.
An infrared thermometer, spectroradiometer and digital video camera were used to observe and document short‐term evolution of surface brightness temperature and morphology at Santiaguito lava dome, Guatemala. The thermometer dataset shows 40–70 minute‐long cooling cycles, each defined by a cooling curve that is both initiated and terminated by rapid increases in temperature due to regular ash venting. The average cooling rate calculated for each cycle range from 0.9 to 1.6°C/min. We applied a two‐component thermal mixture model to the spectroradiometer (0.4–2.5 μm) dataset. The results suggest that the observed surface morphology changed from a cool (120–250°C) crust‐dominated surface with high temperature fractures (>900°C) in the first segment of the measurement period to an isothermal surface at moderately high temperature (350–500°C) during the second segment. We attribute the change in the thermal state of the surface to the physical rearrangement of the dome's surface during the most energetic of the ash eruptions.
The United Nations has targeted Santa Maria volcano, Guatemala, as part of its multidisciplinary "Decade Volcano" program to mitigate volcanic hazards. As part of this program to spotlight one of the world's most dangerous volcanoes, and on the basis of paleomagnetic data, we represent a wholly new interpretation of the temporal evolution of the Santa María volcano. Santa María is a typical, moderate-sized ($$10 km^{3}$$), basaltic-andesite stratovolcano. In 1902, a catastrophic Plinian eruption produced a crater in the south flank of the volcano exposing 250 m of interbedded lava flows, laharic material, and pyroclastic deposits comprising approximately 40% of the cone's infrastructure. A reanalysis of 25 block samples collected by Rose and co-workers and analysis of 48 cores from eight newly sampled lava flows reconfirms and refines the geomagnetic excursion. The resulting geomagnetic waveform is strongly correlatable with that of the 25 to 28 ka Mono Lake excursion. By inference, the latter 40% of the cone's volume ($$4 km^{3}$$) was emplaced in a 1000-3000 yr period with cone construction ending about 25 ka. The corresponding volcanic flux rate ranges from $$0.13 m^{3}/s to 0.04 m^{3}/s$$; a range similar to young, active stratovolcanoes along the Central American arc. Extrapolating a flux of $$0.13 m^{3}/s to 0.04 m^{3}/s$$ throughout the entire construction of Santa Maria suggests that cone growth began between 27.5-32.5 ka. However, up to $$20 km^{3}$$ of dacite tephra was ejected in the 1902 Plinian eruption, suggesting that the magma system feeding Santa Maria remained active during the past 25,000 yr. Assuming a geologically reasonable, constant flux rate of $$0.13 m^{3}/s$$, a cumulative volume of nearly $$100 km^{3}$$ of magma could have been stored in the magma chamber)s) beneath Santa Maria. Because only $$20 km^{3}$$ of magma was erupted in 1902, as much as $$80 km^{3}$$ of magma, or its solidified complement, remains in situ in the crust. Thus the growth of even a moderate-sized volcano in Central America is complemented by voluminous intrusion of magma into the crust.
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