Impact of tephra falls on Andean communities: The influences of eruption size and weather conditions during the 1999–2001 activity of Tungurahua volcano, Ecuador

Abstract:

Repeated ash fall events have occurred during the 1999-ongoing eruption of Tungurahua volcano, Ecuador, notably during the late 1999 and August 2001 eruptive phases. While the eruptive styles were similar, these two phases had different impacts on nearby rural and urban Andean populations: ash falls in late 1999 had limited effects on human health and farming, whereas the 2001 phase resulted in medical problems, death of animals in livestock, and damages to houses and crops. Here we investigate the origin of this difference by estimating the size of the August 2001 event (VEI, magnitude, intensity), and by comparing monitoring information of the 1999 and 2001 phases (duration, explosion rate, column height, SO2 output rate). The results show that both phases ranked at VEI 3, although the longer 1999 phase was likely larger than the 2001 phase. Mass magnitude (M) and intensity (I) indexes calculated …

Año de publicación:

2012

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