Dept. of Geology & Geophysics
Laramie, WY 82070
Phone: 307-766-3363 (o)
Phone: 307-459-1368 (h)
email: zzhang7 (a) uwyo.edu
Welcome to my homepage!
I graduated from the University of Sciences and Technology of China with a B.S. in Geophysics in July, 2002. And I got a M.S. in Geophysics at Kansas State University in May, 2006. I have been a research assistant in the department of Earth Sciences at Boston University from 2006 to 2008.
My PhD research is currently focussed on seismic characterization of the velocity structure about the 410 km velocity discontinuity which is associated with the pressure induced solid state phase transition between Olivine and Wadsleyite. This characterization is being done using western US broad-band data from the EarthScope Transportable Array and selected PASSCAL experiements.
Previous work (Jasbinsek and Dueker, 2007; Jasbinsek and Dueker, in review) finds that a 20 km thick low velocity layer atop the 410 km Olivine-Wadsleyite phase transition, with a 5-7% shear velocity reduction, is quite common beneath the western U.S.The origin of the layer is suggested to be consistent with the water filter model (Bercovici and Karato, Nature, 2003). A testable hypothesis is that where cold sinking slab will destroy any prior 410 water filter melt layer (It is observed in Ristra SE end).
New transportable array tomograms of velocity structure about the 410 (Macquarie et al., 2008; Burkick et al., 2008 ) show that high velocity material is present about the 410 km discontinuity beneath northern Nevada and west-central Utah.
Thus, we predict that a low velocity zone atop the 410 km discon should be absent in these regions. We are testing this hypothesis by processing TA and Ristra 1.5 data.
Preliminary results will be presented at AGU fall meeting on Tuesday (Dec. 16, 2008).
Another project I will work on is called CREST(Colorado Rockies Experiment and Seismic Transects ). We just deployed 59 seismometers in Rocky Mountain Range in summer 2008. In this project I will work on anisotropy, seismicity and local earthquake tomography.
I also did a project called Cascadia Array for Earthscope by use of seismic tomography and receiver functions at Boston University. CAFE is to elucidate the relationship between ETS (Episodic Tremor and Slip), water pathway, magmetism. Here are two cross-sections in Cascadia, one is tele P wave tomography, the other is tele S wave tomography (it is based on picked S waves, not Vp/Vs). And the result of migration of receiver function.
The CAFE project is still on-going, more data will be processed.