[unav_all] Webinar: A 3-D Model of the Crust and Uppermost Mantle Beneath the Central and Western US by Joint Inversion of Receiver Functions and Surface Wave Dispersion

Andy Frassetto andyf at iris.edu
Wed Oct 17 21:32:35 MDT 2012

Please consider attending a webinar on "A 3-D Model of the Crust and 
Uppermost Mantle Beneath the Central and Western US by Joint Inversion 
of Receiver Functions and Surface Wave Dispersion" on October 25, 2012 
from 3-4 pm EDT. This webinar is sponsored by the Transportable Array 
Working Group, part of the USArray governance.

There are 100 spots available for attendees. To attend, register by 
entering your name and email here: 
https://www2.gotomeeting.com/register/116439258 You will then receive a 
confirmation email containing information about joining the webinar. 
***This same email can be used to unreserve your spot if you ultimately 
cannot attend the webinar.***

The webinar will be recorded and available for viewing afterward. 
Following the presentation there will be the opportunity to ask the 
speaker questions. More information on IRIS research webinars, including 
links to previously recorded presentations, may be found here: 

Please contact Andy Frassetto (andyf at iris.edu) with any additional 

Presenter: Weisen Shen, Department of Physics, University of Colorado at 

Summary: "Rayleigh wave phase velocity maps from ambient noise and 
earthquake data are inverted jointly with receiver functions observed at 
~1400 stations from the USArray Transportable Array west of 85°W 
longitude for data recorded in the years 2005 through 2012 to produce a 
3-D model of shear wave speeds beneath the central and western US to a 
depth of 150 km. Eikonal tomography is applied to ambient noise data to 
produce over 300000 Rayleigh wave phase speed curves and Helmholtz 
tomography is applied to data following 2000 (Ms greater than 4.5) 
earthquakes so that Rayleigh wave dispersion maps are constructed from 8 
sec to 80 sec period with associated uncertainties across the region. 
Harmonic stripping generates back-azimuth independent receiver functions 
with uncertainty estimates for each of the stations. A non-linear 
Bayesian Monte-Carlo method is used to estimate a distribution of Vs 
models beneath each station by jointly interpreting surface wave 
dispersion and receiver functions and their uncertainties. The 
assimilation of receiver functions improves the vertical resolution of 
the model by reducing the range of estimated Moho depths, improving the 
determination of the shear velocity jump across Moho, and improving the 
resolution of the depth of anomalies in the uppermost mantle. A great 
variety of geological and tectonic features are revealed in the 3-D 
model and call for more detailed local to regional scale analysis and 
interpretation. In particular, we will discuss the preliminary model of 
crustal and uppermost mantle structure beneath the Mid-Continental Rift."

System Requirements
PC-based attendees
Required: Windows® 7, Vista, XP or 2003 Server
Macintosh®-based attendees
Required: Mac OS® X 10.5 or newer

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