Observatorio Vulcanológico del Sur del IGP (OVS-IGP) and Observatorio Vulcanológico del INGEMMET (OVI) reported that during 15-21 May explosive activity at Sabancaya was similar to the previous week, with an average of 39 explosions detected per day. The number and magnitude of long-period and hybrid events was low. Gas-and-ash plumes rose as high as 4.2 km above the crater rim and drifted more than 40 km NE, E, and SE. The MIROVA system detected six thermal anomalies.

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)