Fig. 7

Flowchart illustrating the classification choices required for recording instances of volcano deformation in a database. Both the deformation information within the GVP’s VOTW database and the COMET volcano databases start by categorising by volcano using the Smithsonian list of volcanoes active in the Holocene. The GVP VOTW database (orange path) then allows the creation of separate entries for different deformation episodes. Note that although deformation episodes presented here are classified by Holocene volcano, VOTW also includes 1100 Pleistocene volcanoes, which may provide improvements for classification. Episodes are distinguished from each other on the basis of a change in location, change in sign, and temporal separation determined by either the start/stop of deformation, or the start/stop of observation. The COMET deformation catalogue (red path) aims to record InSAR observations for each volcano, with a particular emphasis on null results. In practice, both approaches result in a large number of entries that are defined by the start and end of deformation detection – a classification that depends on both timing of both observation and deformation