High resolution geodesy for active, deforming volcanoes

Lead Research Organisation: University of Bristol
Department Name: Earth Sciences


Some volcanic eruptions have enormous economic and humanitarian costs, but measurements that help anticipate them can reduce their impact. The pathway of the magma to the surface is impossible to observe directly and we must rely on secondary signs such as small earthquakes, gas emission and surface deformation to infer magma movement Our proposed work uses the latter. Specifically, we will use the satellite radar interferometry technique known as InSAR to detect changes of less than 1 cm in the position of the earth's surface. InSAR can measure the pressurisation of magma reservoirs, which typically deforms the ground surface over distances of tens of kilometres and lasts for several years. Yet, it is becoming increasingly clear that there are other signals on volcanoes that are smaller in scale and occur more rapidly for which the current use of InSAR is poorly suited. We plan to observe these signals using the satellite TerraSAR-X, which operates at a shorter wavelength than its predecessors, producing images with 2 m resolution every 11 days. We have chosen to target a range of actively erupting volcanoes in Latin America, whose proximity to major population centres and infrastructure are a particular cause for concern. Radar measurements are especially important in this region since frequent cloud cover can make direct and airborne observations difficult. We will address scientific questions related to the growth of volcanic domes, major instabilities on the flank of the volcanoes and the patterns of surface deformation that accompany eruptive crises. Some volcanoes erupt almost continuously, but with especially dangerous eruptive crises occurring every year or two. At these volcanoes, we will use the frequent TerraSAR-X imagery to learn whether uplift and subsidence occur 1) during the heightened period of earthquakes and explosion lasting several months before a major eruption; 2) rapidly during the eruption itself or 3) more slowly as the volcano relaxes into a quiet period following the eruption. Other volcanoes are forming new lava domes from slow-moving, viscous magma. When new material is added particularly quickly, the dome is very unstable and collapses are accompanied by dangerous flows and ash columns. Subtle features in the high resolution radar images will give us clues as to the state of the dome, its growth rate and collapse events. Finally, low resolution images have shown that the flank of Volcan Arenal in Costa Rica is sliding rapidly downhill as new lava flows and ash falls accumulate - a sudden failure could cause a massive landslide and possibly even trigger a major explosive eruption. The new, higher resolution images will tell us if the volcano flank is moving as a single coherent block, or is actually broken up into a number of smaller blocks moving at different rates. We will work closely with the volcano observatories responsible for monitoring these volcanoes to maximize the practical utility of our work.


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Description We have demonstrated the use of X-band radar satellites such as TerraSAR-X and CosmoSkyMed for volcano monitoring in Latin America and educated volcano observatories in Colombia, Ecuador and Costa Rica in InSAR techniques building for strong future collaborations.

We have shown that the flank deformation at Arenal volcano, Costa Rica is caused by a combination of loading and sliding of shallow units near that edifice and that these processes were not influenced by the 2012 Nicoya Earthquake

We have shown that deformation on the western flank of Tungurahua Volcano, Ecuador occurs during many small eruptions and is associated with the internal structure of the volcanic edifice. We have demonstrated the use of radar amplitude and bistatic radar for measuring volume flux of effusive eruptions and ash fall.
Exploitation Route This provided inspiration for the Committee for Earth Observing Satellites (CEOS) Volcano Disaster Risk Management (DRM) Pilot (I am on the science team), which aims to build a regional volcano monitoring system using multi platform satellite observations. It also led to my involvement with the USGS Powell Centre for Synthesis topic on 'Optimizing satellite resources for the global assessment and mitigation of volcanic hazards'.
Sectors Environment,Government, Democracy and Justice

Description We have demonstrated the use of X-band radar satellites such as TerraSAR-X and CosmoSkyMed for volcano monitoring in Latin America and educated volcano observatories in Colombia, Ecuador and Costa Rica in InSAR techniques building for strong future collaborations.
First Year Of Impact 2013
Sector Environment,Government, Democracy and Justice
Impact Types Societal,Economic,Policy & public services

Description Exploring Global Patterns of Volcanic Deformation with Satellite Radar.
Amount £15,000 (GBP)
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 04/2013 
End 04/2014
Description Streva
Amount £705,479 (GBP)
Funding ID NE/J019984/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 01/2012 
End 01/2017
Description IG-EPN 
Organisation The Geophysical Institute of the National Polytechnic School of Ecuador (IG-EPN)
Country Ecuador 
Sector Academic/University 
PI Contribution Contribution of satellite data and interpretations to monitoring volcanoes in unrest and eruption, including Tungurahua, Cotopaxi, Reventador and Chiles Cerro-Negro. PDRA spent 1 month on secondment. Co-hosting a short course.
Collaborator Contribution Data sharing, particularly of ground-based deformation measurements. Co-hosting a short course.
Impact Joint publications. Research used to inform alert levels with direct impact on policy, society and economics.
Start Year 2013
Description OVSICORI-UNA 
Organisation Vulcanological and Seismological Observatory of Costa Rica
Country Costa Rica 
Sector Academic/University 
PI Contribution Collaboration with Costa Rica's volcano and earthquake monitoring agency (based at the Universidad Nacional).
Start Year 2013