Figure 1

Magmatic vs non-magmatic unrest. A volcano is in a stage of magmatic unrest if volcanic unrest is caused by the migration from a magma reservoir (left), which we are able to recognize as such. If we cannot recognize magma migration (regardless whether it migrates or not), but concern remains high for any other reason, the volcano will be in a state of non-magmatic unrest (right). Magma convection and crystallization in a magma chamber are often not recognized as magma migrations, and thus would results in non-magmatic unrest.