Overall Green alert Volcanic eruption for Poas
in Costa Rica

Event summary

GREEN alert: The Poas Volcanic eruption is unlikely to require external humanitarian assistance based on the exposed population and coping capacity.

GDACS ID VO 1000110
Name: Poas (345040)
Lat/Lon: 10.2 , -84.23
Event Date: 23 Apr 2025 UTC
Exposed Population 30km: About 1390000 people within 30km
Exposed Population 100km: About 4210000 people within 100km
Max Volc. Explosivity Index VEI: 2
Population Exposure Index PEI: 5
Inserted at: 27 Mar 2025 06:50 UTC

GDACS Score

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Indonesia - Volcanic eruption and earthquake (ECHO 26 Mar 2025)Fri, 21 Mar 2025 11:17

  • A new explosive eruption of the Lewotobi Laki-laki volcano, in East Flores regency, East Nusa Tenggara province, has been recorded on 20 March. The ash column reached up to 8 km above the crater.
  • According to media, there were no immediate reports of damage to the nearby villages. Following this event the volcano's alert level was raised from level 3 to level 4, all activities within a radius of 6 km from the crater are forbidden, and people have to avoid the southwest-northeast sector up to 7 km distance from the crater.
  • Furthermore, on 18 March, two earthquakes, the highest of 5.5 M as recorded by national authorities,  occurred in North Tapanuli regency, in North Sumatra province. These seismic events triggered a landslide which resulted in one death, one injured person, two buried houses and 13 damaged houses.
Costa Rica - Volcanic unrest (ECHO 01 Apr 2025)Thu, 27 Mar 2025 10:50

  • Between late February and March, Poás Volcano, located in Alajuela province, 45 km northwest of San José, increased its activity, characterised by eruptions and gas emissions.
  • According to the International Federation of Red Cross and Red Crescent Societies (IFRC), as of March 25, the volcano has maintained a continuous eruption with small but frequent pulses. Moreover, strong odours and, in some cases, ash fall have been reported across several surrounding communities, affecting 460,000 people.
  • The Civil Protection of Costa Rica has issued a yellow warning, placing the cantons of Alajuela, Poás, Grecia, Sarchí, Naranjo, Zarcero and Río Cuarto under alert.
Costa Rica - Volcanic unrest, update (ECHO 28 Apr 2025)Wed, 23 Apr 2025 11:26

  • Poás Volcano, located in Alajuela Province, approximately 45 km northwest of the capital San José, continues to exhibit explosive activity. On 21 April, the Volcanological and Seismological Observatory of Costa Rica (OVSICORI) reported a major eruption, with an ash plume rising up to 2 km above the crater.
  • According to media reports, ashfall from the eruption affected several administrative divisions, including Zarcero, Grecia, Alajuela, Heredia, and San José.
  • The alert level for the volcano remains at 3 (on a scale from 1 to 4), as reported by OVSICORI.
  • Costa Rica’s Civil Protection has placed the cantons of Alajuela, Poás, Grecia, Naranjo, Río Cuarto, Zarcero, and Sarchí under orange and green alerts.
Detailed event map. European Union, 2025. Map produced by EC-JRC.
The boundaries and the names shown on this map do not imply official endorsement or acceptance by the European Union.

Updates on volcanic activity (Smithsonian)

The Smithsonian/USGS Weekly Volcanic Activity Report provides information about global volcanism on a weekly basis. Latest Poas report has been published on 19 Mar 2025 09:07.
The Observatorio Vulcanol?gico y Sismol?gico de Costa Rica-Universidad Nacional (OVSICORI-UNA) reported that eruptive activity at Po?s continued at an elevated level through 18 March. Four significant phreatic eruptions were recorded on 9 March that ejected material as high as 300 m above the lake?s surface and produced a steam-and-gas plume that rose 1 km. The monitoring network did not record eruptive events during 11-12 March. Sulfur dioxide emissions fluctuated; emissions detected in satellite data averaged 344 tons per day (t/d) on 11 March and 472 t/d on 12 March and relatively high concentrations were measured by a gas sensor located at the Visitor Observation Deck on 12 March. Residents in Grecia (16 km SW), Sarch? (18 km SW), and San Gertrudis (13 km SSW) reported a sulfur odor and minor ashfall. A small phreatic eruption occurred at 0536 on 13 March, though continuous and voluminous emissions of steam and gas obscured views of the event. A sequence of small phreatic events was recorded during 1800-2000, culminating in a moderate phreatic eruption at 2000. A plume containing significant amounts of sulfur dioxide, hydrogen sulfide, and tephra drifted NW as far as the SW part of Nicaragua. Sulfur dioxide emissions detected in satellite data averaged 844 t/d. At 2300 instruments located at the visitor building of the Parque Nacional Volc?n Po?s recorded extreme levels of sulfur dioxide gas and particulates in the air; these conditions lasted until around 0300 on 14 March. During 0140-0200 on 14 March a gas monitoring station in San Isidro de Coronado measured high levels of sulfur dioxide gas from a plume that drifted S and E of the Valle Central. Residents of Heredia (28 km SE), Alajuela (21 km S), and San Jos? (33 km SE) reported sulfur odors, minor ashfall, and adverse health effects like respiratory discomfort for both residents and animals. Gas-and-steam emissions continued from both Boca A and Boca C through 18 March. The Alert Level remained at 3 (the second highest level on a four-level scale) and the Aviation Color Code remained at Orange (the second highest color on a four-color scale). Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)
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Latest media headlines

Costa Rica, l’eruzione del vulcano Poás mette in crisi il turismo loca.. 4/26/2025 6:41:00 AM.

Le recenti eruzioni del vulcano Poás, in Costa Rica, hanno fortemente danneggiato il turismo nelle comunità vicine, pur senza effetti diretti come ceneri o gas tossici. La chiusura a tempo indeterminato del Parco Nazionale e la disinformazi
...(more)
Desechan posibilidad de gran terremoto por actividad de volcán tico 4/25/2025 10:23:00 PM.

Aunque los accidentes geológicos como este de la norteña provincia de Alajuela sí pueden generar sismos, estos no alcanzan la magnitud de los terremotos tectónicos, añadió el estudioso del Observatorio Vulcanológico y Sismológico (Ovsicori)
...(more)
¿Puede la actividad del volcán Poás provocar un gran terremoto? 4/25/2025 5:24:00 PM.

Expertos en vulcanología responden a esta interrogante. Ante el aumento en la actividad del volcán Poás, ¿podría desencadenar un gran terremoto? Expertos en vulcanología afirman que este escenario es altamente improbable. Cyril Muller, vul
...(more)
Un nuage de trois kilomètres de haut: le volcan Poás est entré en érup.. 4/25/2025 9:40:00 AM.

Le volcan Poás est entré en éruption au Costa Rica. 23 avril 2025 Lundi au Costa Rica, l''une des attractions touristiques les plus connues du pays s''est réveillée. Le Poás a projeté dans les airs un nuage de cendres d''environ trois kilom
...(more)

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Estimated casualties (PAGER)

USGS estimates the number of casualties for each earthquake for the Prompt Assessment of Global Earthquakes for Response (PAGER) product.
The graph shows the current fatalities estimate.

Exposed population

Data, images, links, services and documents

For this events, GDACS has links to information from the following sources: EC-JRC (32), (2), INGV (2), DesInventar (1), WMO (1), INFORM (2), JSR (1),