There are some GPS stations on the island of Ambrym (used for tectonic studies), but there is no published data on volcanic deformation. Ambrym is a basaltic volcano, with a 12 km wide caldera. Ambrym has an ephemeral lava lake, and has had several recent eruptions. The most recent was in 2015, but smaller eruptions from cones within the caldera have possibly occurred approximately yearly during historical times.