Sources, Ascent and Release of Magma and Hydrothermal Fluids at Restless Calderas: Lessons from Santorini Volcano, Greece and Aluto Volcano, Ethiopia

Friday, 19 December 2014: 4:45 PM
Tamsin A Mather1, William Hutchison1, Michelle Parks2, David M Pyle1, Juliet Biggs3, Paraskevi Nomikou4, Gezahegn Yirgu5, Tobias P Fischer6, Stefano Caliro7 and Giovanni Chiodini7, (1)University of Oxford, Department of Earth Sciences, Oxford, United Kingdom, (2)University of Iceland, Nordic Volcanological Center, Institute of Earth Sciences, Reykjavik, Iceland, (3)University of Bristol, School of Earth Sciences, Bristol, United Kingdom, (4)University of Athens, Faculty of Geology and Geoenvironment, Athens, Greece, (5)Addis Ababa University, School of Earth Sciences, Addis Ababa, Ethiopia, (6)University of New Mexico, Department of Earth and Planetary Sciences, Albuquerque, NM, United States, (7)Istituto Nazionale di Geofisicae Vulcanologia, sezione di Napoli, Osservatorio Vesuviano, Naples, Italy
Understanding the behavior of magma and hydrothermal fluids at restless calderas is important for many reasons. The interplay between the magmatic and hydrothermal systems at caldera-forming volcanoes is key to interpreting many of the geophysical signals measured at the surface used to understand their subsurface state and structure. Several recent studies have highlighted that structural controls may be important in terms of the movements of both types of fluids in the Earth’s crust below volcanoes with implications including hazard management and geothermal prospecting. Caldera-forming systems are often characterized by eruptive activity covering a wide range of size scales and repose intervals. Understanding how these different scales of volcanism at the same system relate to each other is a key science challenge when seeking to understand these types of volcano. This presentation will explore these issues using examples from two caldera-forming systems. Santorini volcano in Greece is a relatively well-studied system that last erupted significantly about 75 years ago and has recently experienced a period of unusual unrest. Aluto volcano in Ethiopia is more poorly studied but has been shown to be actively deforming and is an area of focus for investment in geothermal power in the Main Ethiopian Rift. In each case lessons from field mapping and geochemistry, high-resolution digital elevation models, interferometric synthetic aperture radar (InSAR) and degassing surveys and compositions can be brought together to yield insights into the behavior of these and similar volcanic systems.