Subduction zone volcansim

Satellite radar interferometry has the potential to detect uplift caused by subsurface magma intrusions at unmonitored volcanoes, and provide information that could lead to early warning of volcanic unrest. We are studying arc volcanoes around the world in order to identify and understand the significance of precursory inflation. Our focus areas are the volcanoes in Southeast Asia, Central America and Northern Andes. 

Volcano interaction in Kyushu, southern Japan

 Chaman Fault System

The SAR data acquired by the Japanese ALOS-1 satellite offer opportunities for large-scale surveys of voclanic deformation across an entire arc. Anieri Morales-Rivera did this for the Northern Andes, detecting inflation and subsidence at several volcanoes mostly in Ecuador during the 2007-2011 period. See our paper in GCubed for a description of the observations and interpretations.

 


Cotopaxi, Ecuador, 2015 eruption

 Chaman Fault System

Lahars from glacier-covered Cotopaxi volcano, located a few tens of kilometers south of the Ecuadorian capital of Quito, threaten several communities in Ecuador’s Inter-Andean valley. The volcano started a new phase of eruptions in August 2015, the first eruption since a disastrous eruption in 1877. The eruptions occurred a few months after the establishing of the Geohazard Supersite of the Ecuadorian volcanoes which provides multi-sensor SAR imagery of all the active volcanoes. Anieri Morales-Rivera shows in our paper that InSAR using Cosmo-Skymed SAR picked up a few cm of inflation during 4 months prior to the eruption.


Volcanoes in the Northern Andes

 Chaman Fault System

The SAR data acquired by the Japanese ALOS-1 satellite offer opportunities for large-scale surveys of voclanic deformation across an entire arc. Anieri Morales-Rivera did this for the Northern Andes, detecting inflation and subsidence at several volcanoes mostly in Ecuador during the 2007-2011 period. See our paper in GCubed for a description of the observations and interpretations.


Inflation of Indonesia’s volcanoes

Subduction zone volcansim

Indonesia is home to the world’s most dangerous volcanoes. Estelle Chaussard used InSAR data of the Japanese ALOS-1 satellite for a survey of the volcanic arc. She found that six volcanoes were actively inflating during the 2007-2009 period. At some volcanoes inflation was precursory to significant eruptions. See our GRL paper and our JGR paper .


Magma ascent through the crust

 Chaman Fault System

Why have some arc volcanoes shallow magma reservoirs (at 1-5 km depth) and others much deeper one? What are the controls on the depth of magma accumulation in the crust? Our study of the Indonesian volcanoes showed that most of them have shallow reservoirs (see our GRL paper). The Indonesian volcanic arc is characterized by a strike-slip and extensional tectonic setting. This suggest that the depth of magma storage is controlled by the stress regime. A global study on the correlation between magma chamber depth and geodynamic paramaters describing the upper and the subducting plate confirms that processes in the upper plate control the reservoir depth. Please e-mail Estelle for a copy of our submitted paper.