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Table of Contents for GEON IDV web site Introducing the GEON IDV GEON IDV Displays, and Data from UNAVCO and GEON Download & Run the GEON IDV Tutorial ... How to Use the GEON IDV ... More Tips Data Formats: How to Put Your Data in the IDV

GEON IDV Tutorial

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Part 5 - Tomography in a Globe Display, and Seismic Ray Paths

Get a  new display window for the full Earth globe with main menu choice
"File -> Display -> New -> Display Window -> Globe Display -> One pane."
A new window opens with an empty globe with map lines and a wireframe box. The North pole is centered; drag up to see the conventional
side view. If you like, turn off the wireframe box with menu choice in that window "View -> Show -> Wireframe box" checked off.

Set the Vertical Scale to Min value -6371, Max value 6371, units km (use View->Viewpoint->Vertical Scale main menu choice).

Load the data from the UNAVCO catalog http://geon.unavco.org/unavco/catalog.xml in the Dashboard's Dat Chooser "Catalogs" entry 
box; it should already be there from last time). Click on the blue button by "Seismic Tomography", then click on 
"bksVelPertOn4DegGrid" (11 down), and click Add Source. The Data Type is Grids from an OPeNDAP server.

The Dashboard's Fields says "Vs perturbation (%)."

Make a display of type 3D Surface -> Isosurface.  You can resize the window  or zoom the display  if you like.

You can change the isosurface level with the display control. Try -2.5 [percent] and rotate the globe to see the
rises under the Pacific and Indian oceans.

Right and left arrow will rotate the display around the vertical axis.

Now add the data from the catalog "Global Stain Rate Map Project Data -> No Net Rotation global velocity vectors."
Make a display with "Fields" panel selection "2D -> Derived -> Vectors from ve and vn"; and Displays panel "Vector Plan view." 
In the display control for the new display in the Dashboard, choose  5 for both "Vector Size" and  "Skip Interval."
 
Click the menu choice "View -> Show -> Autorotate."

Click the menu choice "View -> Full Screen."

4 degrees by 16 level seismic global tomography and GSRM plate surface motion vectors

Seismic Ray Paths

The GEON IDV can plot seismic rays paths. The ray path can have only location (latitude, longitude, and depth) or also
have one or more additional values at each point on the path, such as seismic velocity, anisotropy, or temperature.
The ray path can be colored by any additional parameter. Segments of ray pahts can have time values so you can
see time animaiton along the path.

A data file for simple ray path data is is located on the UNAVCO GEON web server at URL 
http://geon.unavco.org/unavco/NETCDF/raypath_P_wave_30deg_p3.nc
This file has no time or parameter values, just latitude, longitude, and depth.

Make sure your globe display window is on top of the flat map display.

Use the Data Chooser's  "URLs" tab. Set "Data Source Type" to "Track files." Enter the URL above into the "URL" box; click Add Source.

In the Fields selector click on the blue "Track" button, then on "Altitude," under Fields. Click Create Display.

You will see a ray path from the Aleutian Islands going to the south, into the mantle.

(Oddly, the display list titles such a display "Altitude Topography 3D Relief")

High Resolution 3D Global Grids

To see high-resolution global 3D grids similar to tomography results use the data source in the catalog
Geomodels : Allan McNamara Mantle Convection Model (temperature).  Make the display the same way as for the 
seismic tomography display.  This is a big data set and it may slow or freeze your computer.
The values are temperature as a fraction of temperature at the core mantle
boundary; 1.0 at the core and 0.0039 at the surface. The higher the value (closer to 1.0) the hotter the temperature surface.
Try an isosurface value of  0.65 to see fins of apparently upwelling temperature. 
Change the color table: right click on the Displays list color bar to see color controls menu. Choose the Basic submenu; item 
"Mantle temperatures."

Allan McNamara's mantle convection model; temperature isosurface value 0.65.

You can make "plan views" -- horizontal cross sections -- in the globe display, which are of course shells at a fixed radius.

The globe display does not yet support full use of vertical cross sections.

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