Q-values and Attenuation of the Shallow Crust Under Uturuncu Volcano, Bolivia

Heather L. McFarlin, Stephen R. McNutt, Glenn Thompson

Research output: Contribution to conferencePresentation

Abstract

Uturuncu Volcano, located in the Altiplano-Puna region of the central Andes, near the border of Bolivia and Chile, has been shown to be inflating at a rate of 1-2 cm/yr over an area that is about 70 km wide. The PLUTONS project deployed 28 broadband seismometers around Uturuncu from April 2009 to October 2012. Several thousand shallow (depth < 20 km) local earthquakes were recorded. Attenuation of seismic waves along travel paths for these local crustal earthquakes can be measured by calculating Q-values, which we have performed using the method of single station spectral ratios by Frankel (1982). Large scatter in the Q-values for various distances and travel times appear to be a function of variations in source depth, focal mechanism, and back azimuth. Preliminary Q-values were calculated for azimuths in 30° increments in sectors around each station. Estimates for Q range from about 60 to 700, with many showing a low Q in the direction of the summit from each station. This suggests that the volcanic pile is more highly attenuating than the surrounding crust.

Original languageAmerican English
StatePublished - Dec 11 2017
EventAGU Fall Meeting -
Duration: Dec 13 2019 → …

Conference

ConferenceAGU Fall Meeting
Period12/13/19 → …

Disciplines

  • Earth Sciences

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