MLOC External Resources

External Resources for MLOC

This section deals with software that is required (or highly recommended) for effective use of mloc, but that is not distributed from this website.


mloc makes extensive use of the Generic Mapping Tools (GMT) software for plotting. The code constructs GMT scripts, runs them automatically to create postscript files, and converts postscript files to pdf. Depending on the specifics of the relocation one or more plots are always made and many others are controlled by the user. The main scripts are saved for each run in a folder with a name ending in _gmt_scripts in case the user wishes to edit a script and re-run it.

The current production release of GMT is version 6.0.0, released November 1, 2019. As of v10.5.0 mloc expects GMT6 to be installed.

Using GMT5

In limited testing GMT5 appears to still work correctly with the standard distribution of mloc, with the exception of plotting topography. There is a work-around that will restore the ability to plot topography/bathymetry under GMT5. If you intend to use GMT5 with mloc, it would be wise to update to the latest version (v5.4.5). You will also need to edit your mloc.conf file to specify plotting with GMT5.

Google Earth

An output file in Keyhole Markup Language (KML) is produced by each run of mloc. Any program that can display a file in KML can be used to view it, but Google Earth is most commonly used. There is no requirement to display the .kml file so it can be ignored if no program is available with which to open it.

A Good Text Editor

Use of mloc requires extensive manipulation of text files, so a strong text editor is extremely useful. Some capabilities that are needed for use with mloc are:

  • Open several hundred files at once and switch quickly between them
  • Open individual files up to several hundred MB in size
  • GREP-style search and replace capability
  • Easy navigation by line number

I have used the commercial program BBEdit for many years in mloc analyses, as well as coding, and recommend it highly.

A PDF Viewer

The graphic output from mloc is all in PDF format. Any PDF reader should be able to display them.

A Line-Fitting Application

The Lg phase is not included in the tau-p software, but mloc can employ a custom travel-time model (linear in epicentral distance) for Lg (command lgtt) to better fit the observed data. mloc includes a command (ttou) to create an output file of the observed Lg travel time data that is suitable for import into any data analysis program that has the capability to fit a straight line, i.e., virtually any data analysis program you can find. I use DataGraph.