Date of Award

2025

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Geology (PhD)

Administrative Home Department

Department of Geological and Mining Engineering and Sciences

Advisor 1

Gregory P. Waite

Advisor 2

Rudiger Escobar Wolf

Committee Member 1

Snehamoy Chatterjee

Committee Member 2

Luke J. Bowman

Committee Member 3

Jeffrey Johnson

Abstract

Lahars are a type of volcanic hazard common in tropical stratovolcanoes. They occur when large amounts of water remobilize unconsolidated volcanic sediments, forming a mixture that flows violently downstream. In the case of Volcán de Fuego, Guatemala, lahars are mainly triggered by intense precipitation during the local rainy season. With dozens of these flows reported on Fuego during the rainy months, they pose a significant risk to people living near active lahar channels. This study aims to characterize critical aspects of lahar activity on Fuego using geophysical records, rainfall measurements, video observations, and computational simulations that help constrain the initiation and propagation mechanisms of these flows. This work shows that measured seismic energy increases and signal frequency content decreases while lahars move from proximal to distal areas of the volcano’s flanks. However, in the long term, seismic characteristics remain unchanged. This information supported the development of a machine learning-based framework to automatically detect lahar activity using geophysical monitoring. These results, combined with rainfall information, also allowed us to describe the control of precipitation on lahar activity. Statistically, rainfall at higher elevations is highly correlated with seismic parameters associated with flow size (e.g., cumulative power amplitude) farther downstream and least correlated with spectral characteristics of lahar signals (e.g., dominant frequencies), meaning rainfall alone is not sufficient to predict internal flow dynamics. This is consistent with a set of hydrologic outputs showing the significance that rainfall at higher elevations has in model accuracy. These results improve our knowledge of such ubiquitous types of volcanic processes and related hazards and can potentially be relevant for the development of mitigation strategies benefiting the communities around Fuego.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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