Poas volcano (Costa Rica) - Smithsonian / USGS Weekly Volcanic Activity Report for 7 September-13 September 2022 (Continuing Activity)
On 9 September OVSICORI-UNA reported that activity at Poás had increased since mid-August, characterized by notably increased seismicity. Seismic signals consisted of tremors with variable amplitudes and durations, prolonged harmonic tremors, and some long-period earthquakes with magnitudes greater than those recorded during 2022; there was no increase in low-frequency earthquakes. The energy of the seismicity had also dramatically increased in the previous few days.
jeu., 8 sept. 2022, 10:0010:00 AM | AUTEUR : VN
Sulfur dioxide emissions around the crater were mainly stable at 100 tons per day, though on a few occasions the concentrations were higher; about 300 tons per day was recorded during 17-18 August and higher than 500 tons per day was recorded on 2 September. The volume of water in Boca A lake had significantly increased during August 2021-September 2022, stabilizing at 1.4 million cubic meters between July and September with minor variations measured from week to week. Convection cells in the lake were more active and a new one formed in the N part of the lake (over the Boca C vent) since mid-August.
OVSICORI-UNA stated that these data indicated disturbances to the shallow (less than 2 km) hydrothermal system and did not reflect an influx of magma. Fumarolic degassing and lake convection continued during 9-13 September.
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)
From: Global Volcanism Program, 2022. Report on Poas. In: Mayberry, G (ed.), Weekly Volcanic Activity Report 31 August-6 September 2022. Smithsonian Institution and US Geological Survey.
mer., 20 avril 2022, 19:07
Poas volcano (Costa Rica) - Smithsonian / USGS Weekly Volcanic Activity Report for 13 April-19 April 2022 (New Activity / Unrest)
OVSICORI-UNA reported that submarine fumaroles in the S part of Poás's Boca A lake and subaerial fumaroles along the E margins continued to produce low-temperature gas emissions during 13-19 April. The lake water continued to convect, and was light gray in color, since the phreatic explosion that had occurred on 6 April at “Orange Fumarola” located in a fumarolic field along the inner N crater wall. For a period of time on 17 April a gas monitoring station in Coronado measured a higher concentration of sulfur dioxide aerosols, between 8.5 and 17.6 micrograms of gas per cubic meter of ambient air, which was higher than the daily average of 6.7. ... Read all
mer., 13 avril 2022, 23:59
Poas volcano (Costa Rica) - Smithsonian / USGS Weekly Volcanic Activity Report for 6 April-12 April 2022 (New Activity / Unrest)
OVSICORI-UNA reported that on 6 April at 0240 a phreatic explosion from a vent called “Orange Fumarola” located in a fumarolic field along the inner N crater wall at Poás generated a plume that rose 500 m above the crater rim. Activity lasted for three minutes. The event caused a small landslide that modified the vent. ... Read all