3-D ambient noise tomography of Llaima Volcano, Chile
Abstract
The ambient seismic field can be used at local scales to estimate subsurface structure. In particular, ambient noise tomography can be used to study the local structure around volcanic edifices and be used to infer the magmatic plumbing. Exhibiting many characteristics of an open-vent volcanic system, Llaima Volcano, Chile experiences periods of relative quiescence, punctuated by periods of volcanic unrest. Following the most recent eruptive period between 2007-2009, the current period of quiescence at Llaima was interrupted by an observed increase in volcano-tectonic activity directly following the 2010 Mw 8.8 Maule earthquake off the coast of south-central Chile. Geochemical evidence points toward the existence of a region of magma storage at shallow depths residing above a deeper magmatic chamber. We use ambient seismic tomography to study the geometry and depths of velocity anomalies beneath the surface of Llaima. We use a continuous ambient seismic dataset collected between January and March 2015. We utilize the complete 9-component Green's tensor to investigate the local surface with Rayleigh and Love waves. Three-dimensional shear wave velocity models are derived from 1D dispersion inversion of 2D group velocity maps. Anisotropic characteristics of the model are investigated, as well as the ambient seismic source directionality. Using existing gravity data and local seismicity, we place our new velocity model(s) in the context of the volcanic system and discuss linkages between magma storage and Llaima's eruption history.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMS018.0010R
- Keywords:
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- 7203 Body waves;
- SEISMOLOGY;
- 7255 Surface waves and free oscillations;
- SEISMOLOGY;
- 7270 Tomography;
- SEISMOLOGY;
- 7299 General or miscellaneous;
- SEISMOLOGY