Building a Volcano Early Warning System (EWS) at Pico

Pico de Orizaba is the highest volcano in Mexico and preserves a glacier at the top. The volcano is an old structure and has experienced several cone collapses and subsequent rebuilds in its eruptive history of less than 600,000 years. Thinking about the potential threat to villages located along the major river drainages, Dr. Blake Weissling and I submitted a GWB proposal to monitor precipitation at altitudes over 4000 m above sea level (asl) and to better characterize the lahar forming zone at proglacial ramp. We also wanted to work on lahar (mud or debris flows) detection and monitoring, and posterior on a lahar-warning system for local habitants.

We faced many challenges from the start, including local bureaucracy issues. Geophysical equipment, made available through the Benemérita Autonomous University of Puebla (BUAP), State Civil Protection and private companies, had to be carried and moved between 4200 and 5300 m asl. Relationships with other institutions, like Institute of Ecology (INECOL) and the National Autonomous University of Mexico (UNAM), along with ‘just mountain friends’ provided crucial help with 4×4 transportation. Drones were pushed to their vertical flying limits in order to get the proximal lahar zone mapped (above 3800 m asl).

When the pandemic arrived in early 2020, all instruments and telemetry component acquisitions from universities were put on complete hold. Student involvement was no longer possible and only the project leaders and one crucial technician undertook field work. However, we used the ‘stay at home’ time for integrating a project webpage into the Seismological and Volcanological Observatory (OSV) at the Earth Sciences Center of the Veracruz University (UV). This new infrastructure and monitoring efforts will be integrated into the OSV in order to guarantee long term sustainability.

More than 15 students were involved during the project execution, several of whom worked on very interesting, virtually supported thesis proposals (geomorphology, hydrology, glacier modelling, lahar modeling, vulnerability studies, etc). Geophysical studies revealed glacier’s ice thickness and structure, as well as the uppermost sediment package thickness at the proglacial ramp; drone mapping showed the shape and characteristics of the main ravine, later used for a susceptibility study; and lahar modeling by using Flo2D software will offer scenario maps for future lahar events.

GWB granted us a one year, no cost extension, which is making it possible to finish the project in a timely manner. In the final stage of our project, we are installing a high-mountain rain monitoring network (Davis, Campbell stations and gauges), two seismic sensors along the main ravine, a camera to visually confirm lahar events, Ubiquity radios, Airfiber antennas, solar panels, and batteries.

Although this project will end in August 2021, our work at the volcano will continue. Our presence there will be supported by the observatory, the lead organization, and other local institutions. The installed infrastructure will need to be maintained, however, should last for several years. Through observing the extraordinary rain events at these altitudes, thresholds can be fixed and an Early Warning System (EWS) can be mounted at the first village to be impacted by a larger lahar event in the future.

We would like to thank the GWB Committee, staff, and SEG Foundation donors for making our work possible.

Photo: L to R: Dr. Blake Weissling, Dr. Katrin Sieron, and Sergio Teran, UTSA master student

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