[unav_all] IRIS WEBINAR - Causes and Consequences of Upper-Mantle Seismic Anisotropy - 4/8, 12 PM Eastern

Andy Frassetto andyf at iris.edu
Fri Apr 3 06:42:24 MDT 2015


Please register for "*Advancing our understanding of the causes and 
consequences of upper-mantle seismic anisotropy*" on April 8, 12:00 PM 
EDT at https://attendee.gotowebinar.com/register/8252320016670849281

*Presenter:* Lars Hansen, Associate Professor, University of Oxford

*Abstract:* Over the past 50 years, observed anisotropy in seismic wave 
propagation has been linked to viscous flow in Earth's upper mantle. The 
generally straightforward correlation of seismically fast directions 
with the flow direction has been borne out through laboratory and field 
observations of crystallographic-preferred orientations (i.e., textures) 
in olivine-rich rocks. Thus, a relationship has been established between 
the micromechanical deformation of olivine and patterns of seismic 
anisotropy. However, as laboratory methods and characterization 
techniques have improved, new insight has been gained into the details 
of olivine textural evolution, which may allow for new geodynamic 
hypotheses to be tested with observations of seismic anisotropy. Here I 
will review recent advances in our understanding of olivine textural 
evolution. New laboratory experiments reveal a protracted evolution rich 
with detail in terms of the symmetry and strength of the resulting 
anisotropy. These data have been used to calibrate models for texture 
development and mechanical anisotropy that can be used to quantify the 
geodynamic consequences of upper mantle anisotropy. I will outline 
several applications of these calibrated models to interpreting 
seismological observations and predicting geodynamic responses.

After registering, you will receive a confirmation email containing 
information on how to attend. *Please note that the webinar software 
limits attendance to 100 participants*; join the webinar early in case 
it is oversubscribed. Recordings are typically posted shortly afterwards 
at: https://www.youtube.com/playlist?list=PLD4D607C2FA317E6D
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