JJ Cuno Marie K. Takach M. Rivera Rigoberto Aguilar Frank III Tepley F. Garcia-Arenal Christopher Harpel 2023 <div id="Abs1-section" class="c-article-section"><div id="Abs1-content" class="c-article-section__content"><p>Between 38.5&nbsp;ka&nbsp;cal BP and 32.4&nbsp;ka&nbsp;cal BP, a dacitic Volcanic Explosivity Index 5 eruption at Misti volcano emplaced the Sacarosa tephra-fall deposit. Its biotite phenocrysts, fine grain size, scarce lithics, and abundant loose crystals characterize the deposit at locations sampled. The eruption’s ~ 800&nbsp;°C magma rose rapidly from ~ 10&nbsp;km depth, culminating in a Plinian eruption which reached a mass eruption rate of 7.7 × 10⁶–4.1 × 10⁷&nbsp;kg/s and emplaced about 3 km³<span>&nbsp;</span>of tephra within tens of hours. The unit comprises two layers of subequal thickness separated by a diffuse contact with the upper distinguished by being slightly coarser and less well sorted than the lower. The deposit’s coarser upper layer indicates either climactic conditions or a lesser degree of fragmentation during the latter half of the eruption. Strong winds distributed the deposit southwest of Misti, where it crops out over at least 800 km²<span>&nbsp;</span>and drapes the present site of Arequipa with up to 100&nbsp;cm of tephra. The Sacarosa deposit is the first among the Cayma stage deposits, a distinctive group of felsic, biotite-bearing units, to be carefully described and its eruption characterized. Several Cayma stage deposits were emplaced by voluminous explosive eruptions similar to the Sacarosa eruption, representing a ~ 8.9–15.5 ky interval of powerful eruptions. Such an explosive eruption today would threaten Arequipa’s over 1,100,000 residents, many of whom live within the Sacarosa deposit’s distribution.</p></div></div> application/pdf 10.1007/s00445-023-01654-z en Springer The late Pleistocene Sacarosa tephra-fall deposit, Misti Volcano, Arequipa, Peru: Its magma, eruption, and implications for past and future activity article