fumarolic activity was recorded. In late 1986 an increased fumarolic activity heralded the onset of a new eruptive period, and satellite images observed the occurrence of black spots where the ice had melted or boiled away. During this time, the death of animals was observed in the area. This period reached a climax in May 1990, when an eruption with a volcanic explosivity index of 2–3 occurred. This eruption threw ash to distances of from the summit and was accompanied by strong earthquake activity and the formation of eruption columns that reached heights of . The eruption and further activity, through 1990, enlarged the summit crater and caused the formation of new rows of fumaroles. Chemical analysis, of the volcanic rocks, suggests that this phase of volcanic activity was started by the injection of mafic magma into the magma chamber. This eruption displaced between 4,000 and 1,500 people in the region. After the large 1990 eruption, the style of activity at Sabancaya changed towards a frequent occurrence of explosive eruptions with however low output, which threw ballistic blocks to distances of about from the summit crater; this pattern of activity is referred to as "Vulcanian eruptions". Ash fall from these eruptions induced melting of the glaciers on Ampato, in 1995 exposing the Mummy Juanita on the latter volcano. These explosive eruptions became less common over time (from paroxysms every 20–30 minutes to only 5–6 eruptions per day) and the proportional amount of fresh volcanic material increased at first; since 1997 discontinuous eruptions generate steam columns no higher than and ejected material is almost entirely lithic. Satellite imagery has evidenced the occurrence of temperature anomalies on Sabancaya on the scale of , probably owing to fumarolic activity. In March and April 2013, fumarolic activity and the occurrence of seismic swarms increased leading to local infrastructure being damaged; an eruption occurred in August 2014. This pulse of activity was accompanied by an increased release of , which was being emitted at a rate of in 2014. Ash was emitted by the volcano multiple times through 2014 and 2015, and there has been steady shallow seismic activity since 2013. A further increase of fumarolic activity was observed in 2016, when new fumaroles appeared and sulfur flux increased to sulfur dioxide. Ash eruptions have occurred since 6 November 2016, with an eruption column high five days later. This renewed activity was accompanied by ground