Abstract
We report on the first study using Seismic Wave Interferometry to determine variations of seismic velocities through time, in the vicinity of Láscar volcano in Chile. Seismic Wave Interferometry has been used as a powerful tool to determine spatial and temporal changes of seismic velocities within the Earth. Spatial variations of seismic velocities are related to heterogeneities of material properties, which are expected to occur in a complex structure. However, temporal changes are indicative of dynamic process within the elastic media, and thus, this tool can be used to monitor dynamic processes at volcanic zones. We find consistent variations on three stations close to the volcano, with dv/v of ±0.6%, most likely related to the inflation/deflation process due to fluid movement of magmatic or hydrothermal origin within the volcanic structure. During the observed period of velocity variation, OVDAS reported an increase of volcanic activity evidenced by the increase of the number of long period seismic events, increase of gas emissions and the formation of incandescence above the crater. We suggest that this tool can contribute to the understanding of volcano related dynamic processes, as well as for routine volcano monitoring purposes.
Highlights
Láscar is a stratovolcano located at 23.95° S, 67.88° W, and 5,592 meters of altitude, at approximately 350 km from the trench separating the Nazca and South American plates (Fig. 1)
We report on the first study using Seismic Wave Interferometry to determine variations of seismic velocities through time, in the vicinity of Láscar volcano in Chile
During the observed period of velocity variation, Observatorio Volcanológico de los Andes del Sur (OVDAS) reported an increase of volcanic activity evidenced by the increase of the number of long period seismic events, increase of gas emissions and the formation of incandescence above the crater
Summary
Láscar is a stratovolcano located at 23.95° S, 67.88° W, and 5,592 meters of altitude, at approximately 350 km from the trench separating the Nazca and South American plates (Fig. 1). Due to the availability of seismic data from 5 broad band stations, near the crater, it poses an opportunity to test if with Seismic Wave Interferometry it is possible to detect changes of velocity around the volcano. If it is possible, it would contribute towards the understanding of the associated processes and could become a tool for monitoring purposes. The Seismic Wave Interferometry methodology consist in quantifying the stretching within the coda, giving the amount seismic velocity variation through time (Campillo, 2006; Snieder, 2006) This methodology has been applied to several volcanic centers worldwide. Since OVDAS is monitoring several volcanic centers in Chile, we asked if this methodology can contribute towards monitoring velocity changes around these volcanoes, by testing on specific case, namely Láscar
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
