Observatorio Vulcanológico del Sur del IGP (OVS-IGP) and Observatorio Vulcanológico del INGEMMET (OVI) reported that explosive activity at Sabancaya increased compared to the previous week; there was an average of 19 explosions recorded per day during 10-16 July. Gas-and-ash plumes rose 3.5 km above the crater rim and drifted more than 40 km NW and E. Sulfur dioxide flux was as high as 2,959 tons per day, recorded on 16 July. The MIROVA system detected six thermal anomalies. An explosion at 0931 on 19 July generated an ash plume that rose 4 km above the crater rim and drifted N.

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