GEOLOGY

Detailed explanation-1: -Active volcanoes have a recent history of eruptions; they are likely to erupt again. Dormant volcanoes have not erupted for a very long time but may erupt at a future time. Extinct volcanoes are not expected to erupt in the future. Inside an active volcano is a chamber in which molten rock, called magma, collects.

Detailed explanation-2: -Most volcanoes provide warnings before an eruption. Magmatic eruptions involve the rise of magma toward the surface, which normally generates detectable earthquakes. It can also deform the ground surface and cause anomalous heat flow or changes in the temperature and chemistry of the groundwater and spring waters.

Detailed explanation-3: -Mauna Loa erupted most recently in 1984, and will erupt again in the future, posing significant risks to people living on the flanks of the volcano.

Detailed explanation-4: -It is difficult to gather enough data to find clear patterns in this wide range of volcanic behaviors. Many locations do not have adequate data due to financial constraints, but sometimes we are looking at the wrong signals. For example, some volcanoes have only one seismometer on them.