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Tracking Secondary Lahar Flow Paths and Characterizing Pulses and Surges Using Infrasound Array Networks at Volcán De Fuego, Guatemala

Session: Infrasound and the Seismo-Acoustic Wavefield [Poster]

Type: Poster

Date: 4/20/2021

Presentation Time: 04:15 PM Pacific

Description: 

Lahars are one of the most impactful hazards at many volcanoes, including at Volcan Fuego (Guatemala). Due to their sudden onset, variations in initiation mechanisms (rainfall, eruption-induced, or spontaneous), and complex flow behavior, lahars remain a major challenge to those studying them. On 1 December 2018, a storm system at Volcan Fuego produced heavy rainfall and a subsequent lahar. This event was detected by permanent, telemetered seismo-acoustic stations along several of the river channels, particularly two stations located along the Las Lajas channel, approximately 7.5 km and 12 km from the summit, on the southeast side of the volcano. To establish the timing, duration, and speed of the lahar, cross-correlated lag times were calculated for the infrasound records within both the infrasound arrays and between the two different arrays. Co-located seismic and acoustic signals are highly correlated and indicate at least 4 or 5 pulses/surges in the lahar with approximately 10 minute intervals between pulses. Flow speeds appeared to decrease from ~8.3m/s to ~6.3m/s over the course of the event. We argue that varying sediment load is reflected by clear fluctuations in infrasound and seismic power recorded at one of the stations. This particular event studied with infrasound provides insight into how lahars occur around Volcán Fuego. When compared with the seismic records, infrasound signal analysis reinforces the importance and utility of this technology to detect and track rain-triggered lahars, as well as quantify the hydrological and geomorphic parameters that characterize these types of flows. Future studies of Volcán Fuego will focus on quantifying the occurrence of these events as rapid gravity mass movements.

Presenting Author: Ashley R. Bosa

Student Presenter: Yes

Authors