Instituto Geofísico del Perú (IGP) reported that moderate levels of eruptive activity continued at Sabancaya during 20-26 March. The monitoring network recorded a range of 5-30 explosions per day. Explosions generated ash plumes that rose as high as 1.1 km above the summit crater and drifted less than 10 km in multiple directions; plume heights were not visible during 24-26 March. Seismic signals associated with the movement of magma and gases were registered; totaled counts ranged between 16 and 76 events per day. Thermal anomalies over the lava dome in the summit crater were identified in satellite images almost daily but were not detected during the night of 22 March. Deformation monitoring data indicated continued slight inflation near the Hualca Hualca sector (4 km N). The Alert Level remained at Orange (the third level on a four-color scale) and the public was reminded to stay at least 12 km away from the summit crater in all directions.

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.

Source: Instituto Geofísico del Perú (IGP)