Accessing seismic near-field information with seismometers: From laboratory constraints to volcano seismic applications

 

PhD Candidate: Johannes Thun

Supervisor: Professor Chris Bean

Funded by: EU (FP7) projects NEMOH and FUTUREVOLC

 

Abstract:

On volcanoes, where seismic events occur in a relatively confined area, we have the chance to install dense networks around the source region. Here, so-called near-field effects can play a major role in the observed waveforms - one possible effect being static ground deformation, which cannot be observed at large distances. This means that we can potentially get a more detailed insight into the process of seismic wave excitation and consequently more information on the state of the volcanic system. However, due to technical limitations of even the latest field instrumentation, recovering such subtle near-field information can be a tricky business. My research is dedicated to understanding how we can process and analyse data from near-field seismic recordings. The resulting constraints have been used on our datasets from Turrialba volcano in Costa Rica, Mount Etna in Sicily and Bardarbunga volcano in Iceland.

 

References:

Thun, J., Lokmer, I., & Bean, C. J. (2015). New observations of displacement steps associated with volcano seismic long-period events, constrained by step table experiments. Geophysical Research Letters, 42(10), 3855–3862. doi:10.1002/2015GL063924

Thun, J., Lokmer, I., Bean, C. J., Eibl, E. P. S., Bergsson, B. H., & Braiden, A. Micrometre-scale deformation observations reveal fundamental controls on geological rifting. Submitted to Scientific Reports.