• Antelope Release 5.5 Linux 2.6.32-220.el6.x86_64 2015-04-21

 

NAME

cluster_cleanup - removes redundant cluster associations for pmelgrid

SYNOPSIS

cluster_cleanup dbin dbout [-pf pffile]

SUPPORT


Contributed code: NO BRTT support.
THIS PIECE OF SOFTWARE WAS CONTRIBUTED BY THE ANTELOPE USER COMMUNITY. BRTT DISCLAIMS ALL OWNERSHIP, LIABILITY, AND SUPPORT FOR THIS PIECE OF SOFTWARE.

FOR HELP WITH THIS PIECE OF SOFTWARE, PLEASE CONTACT THE CONTRIBUTING AUTHOR.

DESCRIPTION

This program is part of a suite of programs connected to what is best called pmelgrid. This is a relocation method that uses multiple event location in combination with a (normally) three-dimensional grid of control points. Preliminary hypocenter locations are associated to points in space with a companion program cluster (cluster.1). Experience has show that the current algorithm used in cluster frequently builds completely or nearly completely redundant associations with neighboring grid points. This program aims to remove redundant grid associations.

The algorithm used here occurs in two stages of reduction. The program first opens an extension table called "hypocentroid" in an input database. It loads a grid file from the database controlled by a parameter file definition. The program checks the location of computed hypocentroids in the input database relative to each grid point. If multiple grid points have hypocentroids that fall within the same grid cell the program chooses the one with the maximum number of event associations and caches this information internally. The program then enters an (optional) secondary reduction controlled by the parameter redundant_check_method. The secondary algorithm aims to remove clusters that contain completely duplicate lists of evids or ones that are total subsets of another with larger counts.

OPTIONS

The -pf parameter can be used to use an alternative to the standard pffile derived from the program name -- the usual Antelope convention.

PARAMETER FILE

gridname is a string parameter used to identify the GCLgrid that contains the set of control points to be used by the program.

redundant_check_method controls the secondary removal algorithm. Must be one of three possible string or the program will abort with an exception noting this condition. The allowed values for this parameter are: (1) exact, (2) maximum_associations, or (3) distance_only. If exact is used, only clusters with an exact match of evids will be deleted in the secondary scan. If maximum_association is used, clusters are compared by pairs and if one cluster is a complete subset of the other (i.e. all evids in one occur in the other) the member with the smaller count is discarded. Finally, if set to distance_only the secondary removal algorithm is completely bypassed.

SEE ALSO

cluster(1), dbpmel(1), makegclgrid(1)

BUGS AND CAVEATS

The program is not very general. It will only work with GCLgrid objects stored in a database. The database design of the hypocentroid and cluster tables do not require this.

AUTHOR

Gary L. Pavlis
Dept. of Geol. Sci.
1001 East 10th Street
Bloomington, IN 47405
pavlis@indiana.edu


Antelope User Group Contributed Software
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