Curtin/CSIRO Geophysics Seminar, 30th June 2022
Seismic attenuation parameters in volcanic rocks at a variety of scales
Date: Thursday, 30th of June, 2022
Time: 1:30 PM – 2:30 PM
Location: CSIRO/ARRC Auditorium, 26 Dick Perry Avenue, Kensington; MS Teams
Presenter: Dr Pilar Di Martino
Interpretation of seismic data is the most common geophysical method used for mapping and characterizing the interior of the Earth. However, an important portion of this data is attenuated by seismic scattering and absorption, which manifest themselves as seismic coda waves. Much uncertainty exists about the relationship between the stochastic wave-packets comprised in the seismic coda, the total attenuation we can measure from them, and the intrinsic physical properties of the propagating medium.
In this framework, this study explores the connection between attenuation and scattering parameters, with rock properties (petrophysical/mineralogical) and lays down the use of these parameters to contribute to imaging techniques of heterogeneous sequences. This is tackled through: (1) an extensive petrological and mineralogical characterization of volcanic rocks at the laboratory scale; (2) acquiring S-wave waveforms at ultrasonic frequencies and calibrating the recording of the coda waves to perform attenuation analyses; (3) modelling the full seismic wavefield in synthetic samples using spectral element methods; and (4) performing scattering and absorption tomography in a real volcano, using active data recorded at meter spacing.
The findings show the relevance of including stochastic attenuation parameters in the characterization of heterogeneous settings, like volcanoes, in which the analysis of phases provides insufficient details on the interactive processes taking place.
Short biography:
Pilar just completed her PhD through a joint programme between the University of Aberdeen and Curtin University (http://aberdeencurtinalliance.org/ ). During her time at Curtin (2019), she was based at the Centre for Exploration Geophysics working on connecting ultrasonic attenuation parameters with rock physical properties. Pilar recently joined Schlumberger in Milan as a geophysicist.