2022-07-27
Where there are volcanoes, the earth shakes frequently. In these regions, earthquakes often herald impending volcanic unrest. Both earthquakes and volcanoes occur mainly at the boundaries of shifting tectonic plates. One typical example is Guatemala: the country, located in Central America and sitting on the middle America Trench, has 43 volcanic systems, 25 of which are considered active and a subset of three (Pacaya, Fuego and Santiaguito) produce daily eruptive activity. Like earthquakes, volcanic activity and associated hazards are hard to predict and require close monitoring. This typically includes a seismic network that can measure background activity and allows response to events in real-time, potentially providing warnings to the local population before volcanic hazards threaten their lives. The Swiss Seismological Service (SED) at ETH Zurich is currently just involved in such a project in Guatemala.
Read more...With the support of the Swiss Agency for Development and Cooperation (SDC) and in collaboration with the Guatemalan NGO Vivamos Mejor, the SED is supporting the Guatemalan National Institute for Seismology, Vulcanology, Meteorology and Hydrology (INSIVUMEH) to establish seismic monitoring of Santiaguito, one of Guatemala’s active volcanoes. This collaboration is part of a major SDC project that aims to mitigate the risk from Santiaguito to the local population. Located in southwest Guatemala, Santiaguito is considered to be the volcano with the highest risk in Central America. Tracking seismic activity under the volcano with high precision can allow scientists to better predict eruptive phases. Additional major hazards at Santiaguito also include violent mudflows (lahars) and catastrophic pyroclastic flows, which contain a mixture of rocks, gas, ash and travel very rapidly. These two hazards pose a high risk for the surrounding communities.
INSIVUMEH is currently installing a seismic network on and around the volcano. The role of the SED team is first to help ensure a successful network deployment and data processing. Therefore, researchers from the SED travelled to Guatemala at the end of June to review plans and progress for the seismic network and associated processing. In addition, the team had the opportunity to visit the volcano and better understand the hazards it poses to local communities. The network is expected to be completed this summer. By the end of the year, an event catalogue will become available with examples of seismic records of lahar flows and volcano-tectonic earthquakes. Through previous research projects in Central America to build Earthquake Early Warning (EWARNICA / ATTAC), the SED has established a strong relationship with INSIVUMEH and can rely on previous experience in this region and in Guatemala in particular.
Once the network is operational, the SED team will work to develop scientific tools to improve the monitoring of Santiaguito. During the two-year project, they aim to build a velocity model that will help improve our understanding of volcano-tectonic seismicity and allow the tracking of evolving seismicity. Furthermore, a method will be developed to rapidly detect lahar flows on the volcano's upper slopes so that warnings may be provided to communities downstream.