Volcanic activity in Costa Rica and Nicaragua in 1954

The volcanic activity in Costa Rica in 1954 was limited chiefly to Irazú and Poás volcanoes, although fumarolic activity was reported at Rincon de la Vieja. The activity of Irazú is entirely fumarolic and of about the same intensity as in previous years. Volcano Poás, which had maintained a geyser‐like activity from a lake which filled the bottom of the active crater for many years, began a new eruption in March or April, 1953. This, which appears to be a major eruption, is continuing with a large gas column frequently visible from San Jose' and some fresh ash, cinders, and scoria on the upper slopes of the active cone. The volcanic activity in Nicaragua was limited to the following vents: (1) Concepción has been in a mild state of activity since 1948. The explosions, which sent out a cloud of gas, occur at intervals of about 30 minutes. (2) Santiago, which has been in a vigorous state of fumarolic activity since 1947, is continuing with some increase in the volume of gas and a corresponding increase in the area in which vegetation is being damaged. (3) Momotombo exhibited fumarolic activity at the summit crater in about the same intensity as in previous years. (4) Las Pilas began fumarolic activity in October, 1952, which has increased steadily in volume. The activity is localized along a fracture near the summit. (5) Cerro Negro contains some active furnaroles in the summit crater. (6) Telica has vigorous fumarolic activity in the summit crater in about the same intensity as in previous years. (7) El Viejo is reported to have some furnaroles in the crater but none were observed in a flight over it in a small plane.