First year of magnetotelluric observations at Villarrica volcano, Southern Andes

Villarrica volcano is located in the Southern Andes, one of the world's most productive volcanic arcs of the last decades and stands as the most active volcano in South America, in terms of the number of registered eruptive episodes. Besides its large eruptive record, Villarrica has other particularities, such as being currently an open conduit volcano providing a pathway through which volatiles and magma rise to the surface forming a persistent lava lake at its crater. These features make Villarrica one of the most relevant volcanoes to study along the Andes, and efforts to characterize its internal magmatic structure have arisen during recent years. Along with geochemical and geophysical measurements normally used to image the magmatic system of this volcano, the use of monitoring methods to analyze different changes in time are needed to improve the understanding of active volcanic systems such this one. Through a research project to test the capabilities of magnetotellurics as a volcano monitoring tool, a first permanent broad-band magnetotelluric station was installed at Villarrica volcano during January 2023, and has been measuring since then. Even considering the limitations of a single station experiment, interesting changes in magnetotelluric parameters measured during 2023 and beginning of 2024 have been estimated, and compared to other geophysical and geological parameters measured during this time, aiming to improve our monitoring capabilities and provide new insights into the magmatic processes at one of the most active volcanoes in the Andes. • New geophysical measurements at the most active volcano of the Southern Andes. • Testing magnetotellurics as a monitoring technique for volcanic activity. • Changes in magnetotelluric parameters are analyzed with other monitoring data.