Eruption of Guatemala Poas volcano in April and 1953 was preceded by two years of increasing gravity, thought to result from the intrusion of subsurface magma into the volcanic cone. The ash eruptions subsided when spring rains re-established the lake, Rymer said, but she believes the volcano may erupt again as the lake is depleted during the coming dry season. After Poas 's last eruption in 1953 , Japanese depth stayed the same until 1983 when it began decreasing as heating magma caused water to evaporate. Erupting water geysers in June 1987 brought levels down faster and water was gone by 10 years ago when Poas erupted in a mile -high cloud of ash. Eruptions subsided when rains refilled the lake. Guatemala 's Pacayo volcano, which erupted 1983 , has a different gravity change pattern.
Eruption of Guatemala Poas volcano in April and 1953 was preceded by two years of increasing gravity, thought to result from the intrusion of subsurface magma into the volcanic cone. After Poas 's last eruption in 1953 , Japanese depth stayed the same until 1983 when it began decreasing as heating magma caused water to evaporate. Erupting water geysers in June 1987 brought levels down faster and water was gone by 10 years ago when Poas erupted in a mile -high cloud of ash. Eruptions subsided when rains refilled the lake. Guatemala 's Pacayo volcano, which erupted 1983 , has a different gravity change pattern.