Cotopaxi – stratovolcano, Ecuador

About the volcano

Cotopaxi is a near-perfect glaciated cone south of Quito. Its eruptions are dangerous above all because they melt ice: in 1877 lahars – volcanic mudflows – ran more than a hundred kilometres down the valleys, reaching both the Pacific and the Amazon basin. Today the towns of the Latacunga valley and the outskirts of Quito lie in their path. The volcano woke in 2015 after decades of quiet and was active again in 2022–2023, so Ecuador's Geophysical Institute keeps a dense sensor network around it.

Eruption history

VEI – Volcanic Explosivity Index: 0 = lava outpouring, 4 = like Eyjafjallajökull 2010, 6 = like Pinatubo 1991, 7 = like Tambora 1815. The scale is logarithmic – each step is about 10 times more material.

Start	End	VEI	Vent and dating
21 October 2022	6 July 2023	2	Summit crater · Observations: Reported
14 August 2015	24 January 2016	2	Summit crater · Observations: Reported
2 July 1940	—	2	Observations: Reported
2 February 1939	—	2	Observations: Reported
2 July 1931	—	2	Observations: Reported
2 July 1926	—	2	Observations: Reported
2 July 1922	—	2	Observations: Reported
2 July 1908	2 July 1914	1	Observations: Reported
16 June 1907	—	2	Observations: Reported
21 August 1906	19 September 1906	2	Observations: Reported
2 July 1905	—	2	Observations: Reported
26 September 1903	16 December 1904	3	Observations: Reported
2 July 1895	—	2	Observations: Reported
16 January 1886	—	2	Observations: Reported
23 July 1885	—	2	Observations: Reported
16 December 1883	—	2	Observations: Reported
16 August 1883	—	2	Observations: Reported
16 January 1882	16 March 1882	2	Observations: Reported
16 February 1880	16 July 1880	3	Observations: Reported
26 February 1879	19 June 1879	2	Observations: Reported
23 August 1878	24 August 1878	2	Observations: Reported
16 January 1877	2 September 1877	4	Observations: Reported
2 July 1870	2 July 1876	2	Observations: Reported
16 July 1869	16 August 1869	3	Observations: Reported
15 August 1868	16 August 1868	2	Observations: Reported
2 July 1867	—	2	Observations: Reported
21 September 1866	26 September 1866	2	Observations: Reported
2 July 1863	—	2	Observations: Reported
2 July 1860	2 July 1862	2	Observations: Reported
2 July 1859	—	2	Observations: Reported
16 November 1858	16 December 1858	2	Observations: Reported
2 July 1857	—	2	Observations: Reported
16 October 1856	16 December 1856	2	Observations: Reported
16 May 1856	—	2	Observations: Reported
16 November 1855	—	2	Observations: Reported
14 September 1854	—	2	Observations: Reported
3 April 1854	—	2	Observations: Reported
13 September 1853	15 September 1853	3	Observations: Reported
2 July 1852	—	2	Observations: Reported
16 June 1851	—	2	Observations: Reported
2 July 1850	—	2	Observations: Reported
16 April 1845	—	2	Observations: Reported
2 July 1844	—	2	Observations: Reported
4 January 1803	5 January 1803	3	Observations: Reported
4 April 1768	—	4	Observations: Reported
10 February 1766	December 1766	3	Observations: Reported
2 September 1750	4 September 1750	2	Observations: Reported
1747	1749	2	Observations: Reported
February 1746	—	2	Observations: Reported
May 1744	December 1744	4	Observations: Reported
27 September 1743	4 October 1743	2	Observations: Reported
April 1743	—	3	Observations: Reported
9 December 1742	—	3	Observations: Reported
15 June 1742	July 1742	3	Observations: Reported
1740	1741	2	Observations: Reported
1738	—	2	Observations: Reported
1698	—	3	Observations: Reported
June 1534	July 1534	4	Observations: Reported
October 1533	November 1533	2	Observations: Reported
15 November 1532	—	4	Observations: Reported
c. 1350	—	4	Correlation: Tephrochronology
1260 ± 150 years	—	?	Correlation: Tephrochronology
1130 ± 75 years	—	5	Isotopic: 14C (uncalibrated)
c. 950	—	3	Correlation: Tephrochronology
770 ± 75 years	—	4	Isotopic: 14C (uncalibrated)
740 ± 75 years	—	4	Isotopic: 14C (uncalibrated)
550 ± 200 years	—	?	Correlation: Tephrochronology
370 ± 200 years	—	?	Correlation: Tephrochronology
180 ± 100 years	—	4	Isotopic: 14C (uncalibrated)
c. 150	—	4	Correlation: Tephrochronology
70 ± 150 years	—	4	Isotopic: 14C (uncalibrated)
c. 50 BCE	—	3	Correlation: Tephrochronology
230 BCE ± 200 years	—	4	Isotopic: 14C (uncalibrated)
c. 400 BCE	—	4	Correlation: Tephrochronology
c. 1,050 BCE	—	4	Correlation: Tephrochronology
1,510 BCE ± 150 years	—	?	Isotopic: 14C (uncalibrated)
c. 2,050 BCE	—	5	Correlation: Tephrochronology
2,220 BCE ± 100 years	—	?	Isotopic: 14C (uncalibrated)
2,250 BCE	—	?	Correlation: Tephrochronology
2,640 BCE ± 200 years	—	5	Isotopic: 14C (uncalibrated)
3,280 BCE ± 500 years	—	5	Correlation: Tephrochronology
3,880 BCE ± 75 years	—	5	Isotopic: 14C (uncalibrated)
4,350 BCE ± 75 years	—	5	Isotopic: 14C (uncalibrated)
5,820 BCE ± 75 years	—	5	Isotopic: 14C (uncalibrated)
7,690 BCE ± 75 years	—	2	Isotopic: 14C (uncalibrated)

Data: Global Volcanism Program, Smithsonian Institution (#352050) · Wikipedia (pl) · Wikipedia (en)