zmap a tool for analyses of seismicity patterns typical applications ...

• First rename mydata into a: a = mydata; then start zmap and type: startwitha
• Use the ‘Import Filter’ option from the ZMAP menu, and select the ASCII
import filter.
To get your data into ASCII column format, you can use various tools. On a PC, I often
use textpad (http://www.textpad.com/). In block selection mode, you can delete columns,
and by copying and pasting a blank column, you can add blanks between dates. On a
UNIX workstation, cut and paste work well:
cut –c4-8 catalog.dat > year
cut –c9-10 catalog.dat > month
…
paste long lat year month … > mydata.dat
which will be a tab separated file that can be readily read into Matlab.
Other options to import your data: Writing your own import filters
A second option to import your data is to write your own import filter. A number of
existing filters are listed in the ./importfilters directory. When you choose “Import Data”
from the ZMAP menu, an window will list all available filters:
Select a filter and choose “Import”, then select the name of the file to be imported. The
filters generally will try to read the entire data matrix at once. If this fails, it will read line
by line and report lines that could not be imported.
To design a filter that fits you data format is relatively easy. Lets assume that you would
like to read in the SCEC DC earthquake catalog for 2001
(http://www.scecdc.scec.org/ftp/catalogs/SCEC_DC/2001.cat). The first few lines are
shown below.
2001/01/01 01:16:25.7 le 1.0 h 35.123 -118.538 5.2 A 9172298 0 0 0 0
2001/01/01 01:21:55.9 le 1.6 h 35.047 -119.083 10.9 A 9172300 0 0 0 0
55