Ambrym is a large basaltic shield volcano located in the Vanuatu archipelago, part of the New Hebrides volcanic arc. It features a 12-km-wide caldera formed by a massive Plinian eruption approximately 1,900 years ago. Within this caldera are two active cones, Marum and Benbow, which are known for their persistent lava lakes, though these drained in late 2018. The volcano is characterised by frequent activity, including explosive eruptions, lava flows, ash plumes, and gas emissions.
November 2024 Update
Ambrym Volcano exhibited a new effusive eruption on November 1st, 2024, originating from the Benbow crater. Evidence suggests fire fountaining likely occurred at the active northern “son of Benbow” vent, which has displayed eruptive activity in April 2022, December 2023, and January 2024. Radar data indicates the presence of lava flows associated with this eruption. An incandescent glow was visible on the Vanuatu Meteorology and Geohazards Department web camera. Increased gas output accompanies such activity, with sulfur dioxide (SO2) mass reaching nearly 300 tons on November 1st. Additionally, a minor ash plume, reaching heights of 1-2 km, was detected by NOAA/CIMSS satellite data.
High thermal anomaly – 621 MW (MODIS) recorded over Benbow’s crater.
This pattern of intermittent eruptions is characteristic of the volcano’s current phase of activity.
Significant Ground Deformation Detected
An interferogram produced by Sentinel-1 (InSAR) (2024-11-11 with ref of 2024-10-30 dt=12 days) shows a complex pattern of concentric fringes and dense fringe patterns, which indicate rapid or a steep deformation gradient.
Significant ground deformation is occurring, likely related to magma movement beneath the caldera and dike intrusion. It represents the most significant ground deformation observed at Ambrym since the draining of the lava lakes in 2018.
This rapid and significant inflation suggests a heightened potential for a new eruption, underscoring the critical need for continuous and vigilant monitoring of Ambrym Volcano.