Yannick Withoos, Postgraduate Researcher

Hazardous explosive eruptions at a flooded caldera volcano, Philippines

Contact DetailsYannick Withoos

Project Overview

I am researching the prehistoric caldera-forming eruptions of Taal volcano in the Philippines. It is likely that some of these eruptions were of a large phreatomagmatic style, which is a very dangerous and understudied eruption style. Taal volcano is only 50 km south of the capital city Manila, which has a population of 1.78 million. Consequently, it is paramount that we better understand what the possible impacts of such wide-reaching caldera-forming eruptions could be. My main research methods include fieldwork around Taal caldera. I also collect samples from here to analyse back at Leicester. The methods of analysis include petrography (both optical and electron microscopes), granulometry, and XRF analysis. Using a combination of lab and field techniques I hope to better describe each eruption unit and depositional facies produced by Taal’s caldera-forming eruptions, as well as gain a better understanding about how they eruptions occurred.

Research Theme

Solid Earth

Research Questions

  • How many prehistoric eruptions have occurred at Taal and how many of these involved caldera collapses?
  • What are the depositional facies produced by Taal’s prehistoric eruptions?
  • Does the juvenile chemistry change between eruptions and does the chemistry affect eruption style?
  • How many indicators of magma-water interaction do we find at Taal and do these coincide with what is found other large-scale phreatomagmatic eruptions?
  • How many eruptions were magmatic vs. phreatomagmatic?


Withoos, Y, Branney, M, Barry, T, Miles, A, 2018. ‘How do giant flooded caldera volcanoes erupt? Repeated phreatomagmatic ignimbrite eruptions at Taal Caldera, Philippines’ in the Program for Cities on Volcanoes 10, Naples 2018.

Withoos, Y and Cashman, K, 2018. ‘An ash shape and componentry study of the 2015 – 2016 eruption of Momotombo, Nicaragua’ in the Scientific Program for the Volcanic and Magmatic Studies Group Meeting Leeds 2018.

Hernández, P.A., Norrie, J, Withoos, Y, García-Merino, M, Melián, G, Padrón, E, Barrancos, J, Padilla, G, Rodríguez, F, Pérez, N.M., 2017. ‘Diffuse CO2 degassing monitoring of the oceanic active volcanic island of El Hierro, Canary Islands, Spain’ in Geophysical Research Abstracts 19, EGU General Assembly Vienna 2017.

El Hierro, Canary Islands, Spain’ in Geophysical Research Abstracts 19, EGU General Assembly Vienna 2017

Further Links

CENTA NERC DTP profile: http://www.centa.org.uk/about/students/yannickwithoos/

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