In an Instituto Geofísico de Perú (IGP) report, a photo showed a fumarolic plume rising above Sabancaya on 8 March. During the third week of March, a bluish colored plume rose 500 m above the crater, possibly indicating sulfur dioxide emissions. On 25 March the seismic network detected a continuing high rate of volcano-tectonic (VT) earthquakes and an increasing number of long-period (LP) events. On 27 March and 1 April VT earthquakes continued to be dominant and located below the NE sector of the crater. The number and amplitude of LP events did not change.

Previously, residents of Sallalli, 11 km S of Sabancaya, reported that fumarolic activity had increased on 5 December 2012. Four earthquakes within 15 km of the crater during 22-23 February caused damage in Maca, 20 km NE. In response, the Instituto Geofísico de Perú (IGP) installed seismic stations and recorded hundreds of earthquakes per day.

INGEMMET also installed monitoring equipment, and in partnership with IGP increased monitoring efforts. On 27 February scientists observed that the emissions were mostly water vapor, carbon dioxide, and sulfur dioxide. During 28 February-5 March there were 400-500 earthquakes per day recorded, mostly volcano-tectonic events.

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)