Unrest, Eruption and Volcanic impacts in Vanuatu from constellation satellite measurements

The Vanuatu volcanic arc stretches ~1200 km in the southwestern Pacific, includes fifteen major volcanoes, of which seven are currently active, notably the large caldera systems of Ambrym and Ambae and persistent strombolian activity at Yasur.    Over the past decades Ambrym and Ambae have both had major episodes of passive degassing as well as eruptions.  Recent eruptions have led to the evacuations of homes and damage to crops, water supplies and therefore livelihoods of surrounding communities.   

 Satellite imagery has great potential for volcano monitoring in Vanuatu, especially using radar wavelengths, which penetrate through cloud. SAR amplitude can provide information about the distribution of eruptive deposits, the changing shape of topography and recent work has also shown therefore potentially also effusion rate (e.g., Dualeh et al., 2023).  Volcanism in Vanuatu is modified by active hydrothermal systems, local rifting and in some cases caldera topography (Hamling et al., 2019, Shreve et al., 2019, 2022). Deformation measurements suitable for the detection of deeper magmatic processes are challenging due to both the relatively small size of the islands and the limitations in phase coherence due to dense vegetation.  

For this project, the student will use the latest methods in satellite remote sensing to investigate (1) transitions from unrest to eruption at Vanuatu’s active volcanoes and (2) characteristics of the shallow magmatic and hydrothermal zones with the aim of identifying priorities for hazard assessment with satellite imagery.  

This project will combine satellite measurements from a range of radar, optical and infrared instruments to: 

1. Quantify changes to volcanic topography, especially in vent location and shape, lava effusion and crater lakes 

1.  Measure deformation associated with shallow magmatic and hydrothermal processes during unrest using satellite radar of multiple wavelengths 

1. Assess the impacts of degassing and eruptions on surrounding vegetation, including assessing correlations between vegetation health and degassing flux 

 This student will be supervised by scientists at the University of Leeds (Ebmeier, Ferguson) and at GNS, New Zealand (Hamling, Kilgour).   GNS (www.gns.cri.nz ) are CASE partners for this project and will host the PhD student for research visits during the project.   In the UK the student will be part of the Centre for the Observations and Modelling of Earthquakes, Volcanoes and Tectonics (COMET), which will provide opportunities for training as well as a network of scientists using Earth Observations to research geohazards.    

Related reading: 

Dualeh, E. W., et al. “Rapid pre-explosion increase in dome extrusion rate at La Soufrière, St. Vincent quantified from synthetic aperture radar backscatter.” Earth and Planetary Science Letters 603 (2023): 117980. 

Hamling, Ian J., Sandrine Cevuard, and Esline Garaebiti. “Large‐scale drainage of a complex magmatic system: Observations from the 2018 eruption of Ambrym volcano, Vanuatu.” Geophysical Research Letters 46.9 (2019): 4609-4617. 

Shreve, Tara, et al. “From prodigious volcanic degassing to caldera subsidence and quiescence at Ambrym (Vanuatu): The influence of regional tectonics.” Scientific Reports 9.1 (2019): 18868. 

Shreve, Tara, R. Grandin, and Marie Boichu. “Reservoir depressurization driven by passive gas emissions at Ambrym volcano.” Earth and Planetary Science Letters 584 (2022): 117512.