2008 eruptions

7 phreatic eruptions occurred at Guagua Pichincha Volcano on 1 February 2008. The eruptions were preceded by a magnitude 4.1 earthquake on 6 December 2007.

2003 possible eruption

On 17 April 2003, seismic signals were detected that could have accompanied a minor eruption at Guagua Pichincha, but there was no visual confirmation that an eruption happened.

2002 eruption

On 11 October 2002, 4 phreatic eruptions occurred after several days of heavy rainfall. The eruptions ejected blocks 100-200 m from the vent. Long-period and volcano-tectonic earthquakes and continuous background tremor were recorded until 17 October.
Source: GVP monthly reports

2001 eruption - lava dome growth and ash explosions

Guagua Pichincha's activity in early 2001 consisted principally of gradual lava dome growth. There were ash eruptions on 18, 31 March, and 25 May 2001. The explosion on 25 May produced a ash cloud reaching an altitude of 8.5 km. On 26 November 2001, seismic signals indicated a 20 minute-long phreatic explosion around noon, followed by 16 hours of continuous tremor.

2000 eruptions

During 2000, Guagua Pichincha produced a series of mostly minor ash explosions. A partial collapse of its lava dome which grew in December 199 and January ("dome 8") occurred on 12 July.

1997 phreatic eruptions

During March-October 1997, Guagua Pichincha produced a series of phreatic explosions. The eruptions occurred without any precursory warning signal. Their intensity peaked in May 1997 and the last one was recorded on 18 October 1997. This activity resembled phreatic explosions that occurred in 1981, 1990, and 1993.

1993 eruptions and fatalities

A phreatic explosion at 11h46 local time on 12 March 1993 from Guagua Pichincha's central dome killed 2 young volcanologists. A warning of possible activity had been transmitted to them by radio at 10h30, but for unknown reasons they were still on the lava dome when the eruption occurred.
(source: GVP monthly reports)

1981 reawakening after 100 years of slumber

New activity started in 1981 with phreatic ash explosions and an increase in fumarole activity. This was the first activity after about 100 years of dormancy and started a new cycle of activity.

1660 Plinian eruption of Guagua Pichincha

Quito has been significantly affected several times by eruptions of Guagua Pichincha. The worst of these events occurred in 1660, when as much as 25 cm of ash covered the city. A similar event today, as the its population approaches 2 millions, could spell a major disaster.
The eruption in 1660 began on 28 October 1and lasted for 12 hours. A plinian eruption column developed, reached ca. 25 km altitude and deposited ash and pumice over Quito, which was in a total darkness during the eruption. Pyroclastic flows and surges swept down the flanks of the volcano, but the topographic relief of Rucu Pichincha prevented flows from reaching Quito itself.
The ash fell as far north as Popayan, Columbia (300 km ), and to the south at Loja (430 km ), and to the west it reached the Pacific coast (170 km). Earthquakes during the eruption caused panic in Quito.
There are no reports of fatalities, but the the eruption caused a significant economic downturn to the city and its surrounding region.