Misti volcano in Peru has produced many pyroclastic falls and flows over th
e last 34,000 yr. Three groups are distinguished within the pyroclastic str
atigraphy. The first group is composed of a few mica-bearing, rhyolitic pyr
oclastic fall and flow deposits older than 34,000 yr BP, which represent th
e oldest pyroclastic deposits attributed to Misti. The second group consist
s of several mica-bearing, dacitic fall deposits erupted between 34,000 and
31,200 yr BP. The third group is made up of several tens of amphibole- and
pyroxene-bearing, andesitic pyroclastic-fall and Row deposits. Most deposi
ts of this latter group were erupted bt tween 31,200 and 24,840 yr BP. a fe
w others between 24,840 and 10,670 yr BP, and the last at 1920 pr BP. Most
fallout deposits represent plinian and subplinian eruptions of less than 1
km(3) (DRE). Mineral assemblages and major-element compositions define a hi
gh-K calc-alkaline series, while Sr (> 400 ppm) and Y (< 18 ppm) contents a
re typical of adakitic magmas. The city of Arequipa (700,000 population) is
located 17 km from, and 3500 m lower than, Misti. The four primary volcani
c hazards fur Arequipa include ash and pumice fallout, pyroclastic flow, la
har, and debris avalanche. Those points emphasise the fact that Misti must
be considered a high-risk volcano and deserves more interest than it has re
ceived to date. (C) 2001 Elsevier Science Ltd. Ail rights reserved.