[CIG-ALL] IRIS WEBINAR: Tomographic Study of Lithosphere Dynamics in the Eastern Mediterranean - 3/12, 2 PM Eastern

[Andy Frassetto]

"A Snapshot of Eastern Mediterranean Lithosphere and Upper Mantle: Clues 
for the Demise of Tethys Ocean" will be presented at 2 pm EST (6 pm UTC) 
on Wednesday, 3/12.

Please register *only* if you intend to watch the webinar live: 
https://www2.gotomeeting.com/register/857750082

You will be emailed a confirmation containing a link for watching the 
live broadcast. A recording will be subsequently posted here: 
http://www.youtube.com/user/IRISEnO. Access to older webinars, along 
with related materials and information is found here: 
http://www.iris.edu/hq/webinar/

Presenter: Dr. C. Berk Biryol, Postdoctoral Research Associate, 
University of North Carolina at Chapel Hill

Abstract: The tectonics of the Mediterranean region is characterized by 
an intricate configuration of arcuate subduction zones and mountain 
belts. The evolution and the geodynamics of these zones are controlled 
by closure of Tethys Ocean between converging Eurasia and Africa. The 
interplay between convergence-related compression and slab rollback 
related extension is further complicated by processes such as 
termination of subduction, tearing and detachment of subducting oceanic 
lithosphere. Our recent studies using various seismological techniques 
reveal the complexity of lithospheric and upper mantle structures in the 
Anatolian region using a dataset composed of over 200 seismic stations.

Our body-wave tomography results reveal segmented layout of the Aegean 
and the Cyprus slabs that are separated from each other by a tear as 
wide as 300 km beneath Western Anatolia. The geometry of this tear 
suggests it was formed by differential subduction and rollback rates 
along the Aegean and Cyprus trenches. This configuration of slabs and 
the associated geodynamic setting is consistent with our upper mantle 
seismic anisotropy observations from shear-wave splitting measurements 
favoring a SW direction of asthenospheric flow. We infer that this flow 
is controlled by the differential forces acting on the upper-mantle, 
exerted by the slab-roll-back taking place along the Aegean and the 
Cyprean Subduction Zones. The gaps associated with the slab tears and 
edges are occupied by slow velocity material and underlie major volcanic 
provinces of Anatolia. Recent ambient noise tomography results reveal 
the fragmented nature of the Anatolian lithosphere with seismic velocity 
variations across paleo-suture zones and major active-tectonic features 
such as the North Anatolian Fault Zone.

Overall, our observations hold important clues about the effects of 
Tethys Ocean closure on the structure of subduction zones and 
lithosphere in the eastern Mediterranean.

Please direct any related questions or the name of your favorite seismic 
station to Andy Frassetto (andyf at iris.edu).

System Requirements
PC-based attendees: Windows® 8, 7, Vista, XP or 2003 Server
Mac®-based attendees: Mac OS® X 10.6 or newer
Mobile attendees: iPhone®, iPad®, Android™ phone or Android tablet