Poas Volcano

Updated: Mar 31, 2025 18:00 GMT - refresh

Stratovolcano

Costa Rica, 10.2°N / -84.23°W

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Summit height: 2708 m (8,884 ft)

Current status: minor activity or eruption warning (3 out of 5)

Last update: 31 Mar 2025 (Volcanic Ash Advisory)

Poás is one of Costa Rica´s most active volcanoes, and one of its most frequently visited and prominent ones. It contains a green acid crater lake and during some of its frequent phreatic eruptions, water from the lake is ejected like a geyser.

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Typical eruption style: Phreatic eruptions, sometimes geyser-like ejections of water from the acid crater lake.
Poas volcano eruptions: 1828, 1834, 1838(?), 1860, 1879(?), 1880, 1888-91, 1895, 1898-1907, 1910, 1910, 1914, 1914-15, 1925, 1929, 1941-46, 1948-51, 1952-57, 1958-61, 1963, 1964-65, 1967, 1969, 1970, 1972-73, 1974-75, 1976, 1977, 1977-78, 1978, 1979-80, 1980, 1981, 1987-90, 1991, 1992, 1992-93, 1994, 1996, 2010, 2011, 2012, 2013, 2014, 2016, 2017

Latest nearby earthquakes

Date and Time	Mag / Depth	Distance / Location
Mar 30, 12:28 pm (GMT -6)	2.5 6 km	1.7 km (1 mi) to the S	Costa Rica: 8 km Al Oeste De Varablanca, Heredia.	Info
Tuesday, March 25, 2025 GMT (2 quakes)
Mar 25, 11:28 am (Universal Time)	2.3 4 km	22 km (14 mi) to the W	31 km Al Oeste De Vara Blanca, Costa Rica	Info
Mar 25, 05:28 am (GMT -6)	3.1 6 km	22 km (14 mi) to the W	Costa Rica I FELT IT	Info
Saturday, March 22, 2025 GMT (1 quake)
Mar 22, 02:34 am (Universal Time)	2? 4 km	3 km (1.9 mi) to the N	Costa Rica (unconfirmed)	Info
Thursday, March 20, 2025 GMT (1 quake)
Mar 20, 07:09 pm (Universal Time)	2? 4 km	9.7 km (6.1 mi) to the SE	Costa Rica (unconfirmed)	Info
Wednesday, March 19, 2025 GMT (1 quake)
Mar 19, 05:10 am (Universal Time)	2? 80 km	18 km (11 mi) to the SW	Costa Rica (unconfirmed)	Info

View recent quakes

Background

The broad, well-vegetated edifice of Poás has three craters in a N-S line. The 2708-m-high basaltic-to-dacitic complex stratovolcano is cut by a N-S-trending fissure that extends to the lower northern flank, where a parasite volcano (the Congo stratovolcano) and several explosion craters, or maars, most of them lake-filled, have been created.
Poás has two summit crater lakes. The southermost one, Botos, is cold, clear has not eruptied for about 7500 years. The other crater lake is geothermally heated and -after Kawah Ijen in Indonesia - is probably the world's second most acidic natural lake. Its pH is near zero.
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Source: GVP, Smithsonian Institution

Poas Volcano Photos

Vulkan Poás in Costa Rica (Photo: Astrid_Furrer)

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Significant volcanic eruptions: Poas volcano

In the past 10,000 years, Poas has had at least 61 confirmed volcanic eruptions, out of which 54 are documented by historical records, while the others can be inferred from geological evidence.
Additionally, there are 2 uncertain or discredited eruptions from Poas volcano.

The table below lists all known eruptions (date in bold face) of Poas volcano since around 1900. Updates on the most recent volcanic activity of Poas can be found on the news page of Poas volcano.

Date	Note	VEI
2023 Dec 1 - 2024 May 5	Historical obs./docs.	1
2023 Aug 2 - Aug 11	Historical obs./docs.	1
2022 Apr 6	Crater lake - Fumarola Naranja Historical obs./docs.	1
2019 Feb 7 - Sep 30	Historical obs./docs.	2
2017 Apr 12 - Nov 6	Laguna Caliente Crater Historical obs./docs.	1
2016 Jun 5 - Aug 16	Lake in summit crater Historical obs./docs.	1
2009 Nov 16 ±15 d. - 2014 Oct 13	Historical obs./docs.	1
2009 Jan 12 - Mar 21 ?	Historical obs./docs.	1
2008 Jan 13	Historical obs./docs.	1
2006 Sep 25 - Dec 16	Historical obs./docs.	1
2006 Mar 24	Historical obs./docs.	1
1996 Apr 8	Historical obs./docs.	1
1994 Mar 16 ±15 d. - Oct 16 ±15 d.	Historical obs./docs.	2
1992 Oct 16 ±15 d. - 1993 Sep 16 ±15 d.	Historical obs./docs.	0
1992 Feb 16 ±15 d. - Mar 16 ±15 d.	Historical obs./docs.	1
1991 Mar 6 - Sep 16 ±15 d.	Historical obs./docs.	1
1987 Jun 16 ±15 d. - 1990 Jun 16 ±15 d.	Historical obs./docs.	2
1981 Mar 16 ±15 d. - May 16 ±15 d.	Historical obs./docs.	1
1980 Dec 26	Historical obs./docs.	1
1980 Sep 12	Historical obs./docs.	1
1979 Sep 8 - 1980 Jan 16 ±15 d.	Historical obs./docs.	1
1978 Sep 22 - Dec 16 ±15 d.	Historical obs./docs.	1
1977 Dec 18 - 1978 Jun 15	Historical obs./docs.	2
1977 May 16 ±15 d. - Jul 16 ±15 d.	Historical obs./docs.	1
1976 Jun 21 - Nov 16 ±15 d.	Historical obs./docs.	2
1974 Sep 11 - 1975 Feb 16 ±15 d.	Historical obs./docs.	2
1972 Feb 9 - 1973 Sep 8	Historical obs./docs.	2
1970 Jul 16 ±15 d.	Historical obs./docs.	1
1969 May 3 - Jun 3	Historical obs./docs.	2
1968 Jul 2 ±182 d.	Historical obs./docs.	1
1967 Jan 1	Historical obs./docs.	1
1964 Dec 25 - 1965 Mar 16 ±15 d.	Historical obs./docs.	2
1963 May 23 - Jul 2	Historical obs./docs.	2
1958 Jul 2 ±182 d. - 1961 Jul 3 ?	Historical obs./docs.	2
1952 Mar 23 - 1957 Dec 25	Historical obs./docs.	2
1948 - 1951 Jul 2 ±182 d.	Historical obs./docs.	1
1946 Nov 4 ±4 d.	Historical obs./docs.	1
1941 - 1946	Historical obs./docs.	1
1932 - 1934	Historical obs./docs.	1?
1929	Historical obs./docs.	1
1925	Historical obs./docs.	1
1916	Historical obs./docs.	2
1914 Oct 8 - 1915 May 15 or later	Historical obs./docs.	2
1914 May 30	Historical obs./docs.	2
1910 Sep 12 - Oct 14	Historical obs./docs.	1
1910 Jan 25 - Feb	Historical obs./docs.	2
1898 Dec 29 - 1907 Dec 31 ±365 d.	Historical obs./docs.	1

Remark:

Our list of volcanic eruptions closely follows the database of eruptions of the Smithsonian's Global Volcanism Project (GVP), the internationally most recognized data source for volcanic eruptions, but also includes significant eruptive episodes or related volcano events. "Volcanic eruptions" are usually to be understood as sequences of individual eruptive episodes that can follow each other, or even overlap (if several vents are involved), and can last many years, decades or even longer. For example, the current activity of Stromboli volcano is understood as a single eruption that has been ongoing since 1934.

Sources: NOAA National Centers for Environmental Information (NCEI), Global Significant Volcanic Eruptions Database. doi:10.7289/V5TD9V7K | Global Volcanism Project / Smithsonian Institution

Poas Volcano FAQ

+When was the last eruption of Poas volcano?

The last confirmed eruption of Poas occurred during 2023 - 2024.

+How often does Poas volcano erupt?

Since 1747, Poas volcano has had at least 54 historically documented eruptions. This means that it erupts on average every 5.1 years.
Many eruptions of Poas have lasted more than one year. In total, the volcano has been in eruption during 89 out of 278 years until now. In other words, Poas has been active at least one in 3.1 years on average. Note that this value is likely an underestimate, because the known history of eruptions from Poas is likely incomplete, especially further back in time.

+How active is Poas volcano at present?

Poas volcano is extremely active: Since 1900, it has been frequently active, showing eruptive activity during 77 years out of 126 as of now. The last eruption was from 2023 until 2024 and ended 11 months ago.

+When was the largest eruption of Poas volcano?

The largest eruption of Poas volcano in historic times occurred in 2019. It ranks as a strombolian to vulcanian eruption with a magnitude 2 on the VEI (Volcanic Explosivity Index) scale.

Latest satellite images

See also: Sentinel hub | Landsat 8 | NASA FIRMS

Latest satellite images

Poas Volcano Maps

Below is a selection of maps showing the location and surroundings of the volcano at various resolutions based on aerial-imagery / terrain maps. Feel free to use them for non-commercial purposes on your blog or website as long as you credit them with a link back to this page (click to copy it).