3-D Ambient Noise Tomography of Llaima Volcano, Chile

Llaima is a glaciated, basaltic-andesitic stratocone in the South-Central Andean Volcanic Zone. It is one of the largest and most active volcanoes in Chile. However, uncertainty remains regarding the depths and geometry of where magma is stored and the routes which it takes towards the Earth's surface. To provide a structural framework for the interpretation of petrological and geochemical data, I apply ambient noise tomography (ANT) to produce a 3-D shear wave velocity ( v s ) model of Llaima's magmatic plumbing. The results of this project show slow shear wave velocity anomalies within the upper 8 km of the crust which are interpreted as the locations of upper and lower magma reservoirs. Among the structures that are revealed by fast shear wave velocity anomalies is a geometry that is interpreted as a dike within a cluster of volcano tectonic (VT) activity. This VT cluster has been suggested to have followed the 2010 M8.8 Maule megathrust earthquake off the coast of Chile (Mora-Stock et al. , 2014; Franco, 2019). I use information that has been derived from previous studies such as the coordinates of scoria cones along Llaima's flanks, gravitational anomalies, and local seismicity (which includes the depths and locations of volcano tectonic and long period seismicity) to place the resulting model within a framework that provides insight on the current state of this magmatic system.