Volcanic Hazards Evaluation of Yucamane Volcano, Southern Peru
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Volcanic Hazards Evaluation of Yucamane Volcano, Southern Peru M. Rivera 1 & J. Mariño 1 1Dirección de Geología Ambient al – INGEMMET, Lima, Perú mriv [email protected] Geologic studies, historical registries compilation of volcanic eruptions and observations on Ast er satellite images helped to consider the main volc anic hazards of the Yuc amane v olcano t hat could affect six towns. One of them is Candarave city , located 16 km sout h of the v olcano, where liv es approximately 6000 people. The main v olcanic hazards acc ording t o their f requency include: 1) Tephra-fall, t wo cases are distinguished: emissions of ash and ballistic projections. The f irst hypothesis is bas ed on ash and pumic e lapilli of Pleist ocene and Holocene age located around the v olcano. The most recent Plinian eruption happened ca. 3270 yr B.P. emplaced more that 1 k m 3 of pumic e f all. The second hypothesis is bas ed on t he ballistic blocks t hat measure up to 3 m of diamet er emitted bef ore 3270 y r B.P. loc ated on the west edge of the crater. 2) Lahars, those c an be induc ed by rainstorms and snow-melt. Bas ed on lahar deposits these are f ound in drainages located at 5 km south f lank of the v olcano. 3) Pyroclastic f lows , three cas es are distinguished: block -and-ash f lows t hat can be generated by the growth and destruction of domes. The hy pothesis is based on the pres ence of two deposits of block -and-ash f lows of Pleistoc ene age at 5 km s outh of the crater. Scoria f lows t hat can be generat ed by v ulcanian eruptions, like a Holocene depos it, v isible 5 km sout h of the crater. Pyroclastic surges, bas ed on a pyroclastic surge deposit that measures 60 cm thick t o 6 km in the south f lank of the v olcano (Honda ravine). 4) Rockslide and debris av alanches can be generated by probable collapse of part of the s outh f lank of the v olc ano summit, this in the c ase of v iolent eruption or the growth of a dome within the v olcanic building. .