UDQ (Upside-Down Quakes) is a package (program and data files) to make it possible to view seismicity in three dimensions, using Google Earth or another ‘‘Earth browser.’’ This is done by converting seismicity data (from a catalog) into files in KML, with earthquake depth replaced by elevation, since current browsers do not allow subterranean viewing. The UDQ program reads in a set of commands, which may be typed in directly, or (more repeatably) piped from a file; these commands cause the program to read seismicity data from an input file, and write the information to an output file in KML format.
This output file is then packaged with a set of icons (also part of the distribution) using the zip utility to make a KMZ file, which can be imported into Google Earth.
UDQ includes the ability to:
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Limit what is shown by geographic, temporal, or magnitude boundaries. |
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Split data into different time segments to reduce the load in displaying all the events. |
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Split data into different time segments, with large earthquakes showing up in later segments as semi-transparent icons. This is useful in examining aftershock clusters, where the mainshock can be kept visible for reference. |
The package is distributed as a gzipped tarfile. Uncompressing and untarring this will create a directory udq-1.6 containing the UDQ source and subdirectories containing files of different icons, some example commands, the KML files that should be produced by these examples, documentation, and a location for the executable.
UDQ is written in Fortran-77.
For more information consult the program manual.
March 2009: Version 1.3: initial release.
August 2009: Version 1.5: added altitude scaling, and ability to read ANSS format.