Date of Award

2020

Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Geology (MS)

Administrative Home Department

Department of Geological and Mining Engineering and Sciences

Advisor 1

Rudiger Escobar Wolf

Advisor 2

Paolo Frattini

Committee Member 1

Thomas Oommen

Committee Member 2

Simon Carn

Abstract

Fuego volcano is one of the most active and hazardous volcanoes in the world. It is located in the northern part of the Central American Volcanic Arc in Guatemala and its activity can be characterized by long term, low-level background activity, and sporadic larger explosive eruptions. Its historical observations of eruptions date back to 1531, but it has been erupting vigorously since 2002 with major activity throughout 2018, producing three main eruptions in February, June and November. Its almost persistent activity generates major ashfalls, pyroclastic flows, lava flows; when heavy rains mobilize its deposits, they can form damaging lahars. Phenomena, like pyroclastic flows and lahars, have a very high potential to be hazardous and highly lethal, considering that Fuego is also surrounded by a series of small villages and cities like Escuintla, Masagua or San Miguel Los Lotes.

The sub-plinian eruption that happened between the 3rd and 5th of June 2018 was the deadliest event in the recent history of the volcano. It produced around 20 million m3 airfalll tephra volumes, and about 50 million m3 of pyroclastic flow deposits. This event triggered major lahars descending multiple channels – locally called barrancas – that surround the volcano edifice. More than 12 thousand people of the communities of Sangre de Cristo, Finca Palo Verde and Panimache have been evacuated to escape from the violent eruption.

This project is aimed to study and analyze the volcano changes throughout 2017, i.e., the year right before the June 3rd disruptive event. Although the June 3rd 2018 eruption had the largest and most tragic impact, mainly caused by the generation of pyroclastic density currents, this work shows that significant lahar activity and sediment mobilization occurred already in 2017, associated to explosive eruptive activity that was frequent that year.

Geographical, seasonal and infrastructural restrictions make ground-based monitoring not always practical. Therefore satellite-based remote sensing methods can particularly be beneficial for volcano monitoring.

High-resolution images acquired from a constellation of over 130 cubesats operated by Planet Labs Inc were used for this study. Through the satellite remote sensing data, lahar zones were detected in order to assess hazards caused by volcanic eruptions. Because the approach of automated methods was not successful in delineating the deposits in the barrancas and in the proximal areas, the lahars were visually mapped. This manual interpretation technique allowed to achieve high accuracy for hazard detection and monitoring.

Then, areas of lahars inundation were simulated and mapped using LAHARZ, a Geographical Information System (GIS) code created by the United States Geological Survey. This tool is used to produce hazard maps and evacuation solutions in a short time frame. The detected and simulated lahars zones were compared and verified. A statistical rainfall analysis was performed to see how the rainfall intensity can affect the triggering of the lahars.

The monitoring, mapping and the study of past events could assist volcanic hazard mitigation efforts in Guatemala and other active volcanoes in the world, enabling volcanologists and local governments to predict lahar and minimize the loss of human life and property.

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