The Miravalles area is continually monitored, as some
seismic activity is taking place under and inside the caldera.
However, the last recorded eruption of steam vents was in 1946.
Because the
park contains a large underground heated reservoir, it is the site of a
geothermal
energy plant. The hydrothermal field is a hot-water dominated system,
with
a vapor dominated cap (few tens of meters thick) in some parts of the
geothermal
field.