The Technical and Scientific Committee for volcanic risk management of the Arequipa region (comprised of five groups including IGP's OVS and INGEMMET's OVI) reported 288 explosions at Sabancaya during 21-27 November. Ash plumes rose as high as 4.5 km above the crater rim and drifted 35-40 km E and SE. Sulfur dioxide emissions were as high as 3,300 tonnes/day and deformation was detected on the SE flank. During 28-29 November ash plumes rose 2 km and drifted 30 km S and SE. The Alert level remained at Yellow; the public was warned to stay at least 10 km away from the volcano.

Geological Summary. Sabancaya, located in the saddle NE of Ampato and SE of Hualca Hualca volcanoes, is the youngest of these volcanic centers and the only one to have erupted in historical time. The oldest of the three, Nevado Hualca Hualca, is of probable late-Pliocene to early Pleistocene age. The name Sabancaya (meaning "tongue of fire" in the Quechua language) first appeared in records in 1595 CE, suggesting activity prior to that date. Holocene activity has consisted of Plinian eruptions followed by emission of voluminous andesitic and dacitic lava flows, which form an extensive apron around the volcano on all sides but the south. Records of observed eruptions date back to 1750 CE.

Sources: Instituto Geofísico del Perú (IGP), Instituto Geológico Minero y Metalúrgico (INGEMMET)