How can satellite images help scientists follow changes at the summit of an erupting volcano?
In this episode of the Behind the Science Podcast, host Dr. Paul Flores speaks with Aris Paolo A. Castro, an instructor and master’s student at UP Diliman’s National Institute of Geological Sciences (NIGS), about tracking the growth and collapse of Mayon’s lava domes through remote sensing.
Castro had wanted to become an educator since elementary school. His interest in geology developed during senior high school, when an enthusiastic Earth science teacher helped him decide on his college course. After graduating in 2023, he began teaching while taking master’s classes and preparing for the geologist licensure examination, where he placed sixth. Preparing his lessons also became part of his review, supported by careful time management and studying with friends.
The featured study began as a project for a graduate remote sensing class in 2024. Castro and his partner wanted to apply their coursework to volcanology. Reports of lava dome growth and collapse at Mayon prompted them to reconstruct the sequence using satellite images. Encouraged by their professors, they submitted and presented the work at PhilGEOS, eventually developing it into a published conference paper.
Castro explains that a lava dome forms when thick, viscous lava accumulates near a volcano’s summit. Understanding its growth and destruction matters because dome collapse can generate hazardous pyroclastic density currents. Remote sensing allows researchers to observe these changes from a distance, reducing the need to approach an active summit.
Using Landsat and Sentinel-2 imagery, the researchers combined satellite bands to produce false-color images that highlighted hot volcanic material. Bright orange and yellow features helped them identify changes around the summit and material extending down the slopes. They processed and annotated the images in QGIS, then compared their interpretations with PHIVOLCS bulletins describing rockfalls and pyroclastic density currents.
The team identified five constructive phases and four destructive phases between 20 August 2022 and 8 December 2023. The sequence showed repeated dome growth, collapse, and renewed formation, ending with another constructive phase. Cloud cover and volcanic plumes sometimes obscured the summit, so using two satellite datasets helped fill observational gaps. Castro emphasized the qualitative scope of the work, with measurements of vertical growth remaining outside the study.
The episode also explores the practical demands of starting a research career. Freely available imagery and a laptop capable of running QGIS made the project accessible. Finding time and energy alongside teaching and graduate coursework proved challenging. Castro recalled feeling burned out and learning to take breaks so he could regain enjoyment in his work.
For aspiring researchers, his advice is to “keep asking” and remain willing to learn. He also encouraged students to manage their time and seek help from supervisors and more experienced colleagues. Asking questions, he explained, allows advisers to provide guidance before uncertainty delays the research further.
Hear Castro’s account of turning a classroom project into a publication and finding his footing as a researcher and educator. Behind the Science is a collaboration between the Marine & Earth Science Learning Hub and the UP Resilience Institute.
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Research spotlight:
Castro, A. P. A., Jatulan, P. M. C., Principe, J. A., & Tamondong, A. M. (2026). Spatiotemporal modeling of lava dome evolution of Mt. Mayon during its 2023 eruption using remote sensing data. ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, X-5/W4-2025, 159–164. DOI: 10.5194/isprs-annals-X-5-W4-2025-159-2026.
Know a scientist whose research journey deserves to be heard? Send your nominations in disaster risk reduction and geosciences to upri.educ@up.edu.ph for consideration in a future Behind the Science episode.