Harvard University
3d visualization of earthquake focal mechanisms
Introduction
On maps the focal
solution of earthquakes is often represented as a stereographic
projection of calculated nodal planes with the quadrant shaded where first
arrival of seismic waves at the receiving seismometer is compressive. In
effect this projection looks like a simple beach ball. In a 3d visualisation
environment such as gOcad it becomes desirable to represent focal solution
as actual 3d spheres with shaded quadrants. Here I make available a package
which provides this functionality and other related tasks for the gOcad
environment. It consists of some programs (awk scripts) which create the
objects in a gOcad format and a graphical interface to these programs which
is implemented as a so-called gOcad wizard.
Screenshots
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for full image, 63kb)
First screen of visualization wizard. Specify file name and type for
import. Example pictures on left shows some beach balls.
(click for full image, 32kb)
Choose type of visualization in wizard. Example picture on left shows
nodal planes and P-/T-axes.
(click
for full image, 79kb)
Import attribute field of fpfit file as properties. Example picture
on left shows a point cloud.
(click
for full image, 48kb)
First screen of Filter and Export wizard. There are fields to specify
object, filter values and a file name. Exported files can be reimported
with the visualization wizard.
How to use ?
Please consult the README
file which accompanies the package for usage and installation instructions.
Download
I prepared two archives, one for Irix and one for Linux. Except for the
scripts and the wizard which should run on any architecture, they contain
precompiled binaries of the proj
program which is used for conversion of geographic coordinates into UTM
coordinates.
Download (free for academic use),
Comments
If you like this package and use it for your work, please contact
the author.
Enjoy,
A. Plesch
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7.7.00
(click for full image, 32kb)
(click
for full image, 79kb)
(click
for full image, 48kb)