This documentation has not been updated since 2011. Visit the official GISMO site on github.com to access the latest documentation and to download the current version.

GISMO toolbox for seismology
Geophysical Institute
Alaska Volcano Observatory
University of Alaska Fairbanks

The GISMO toolbox

The GISMO toolbox is a framework for rapid development of seismic data analysis codes built on a common platform that encourages code sharing. GISMO stands for GI Seismology Matlab Objects. The GISMO toolbox consists of:

  1. core data types (classes) for handling different types of seismic data (e.g. waveform data, catalog data, instrument responses),
  2. core products built on these (e.g. the correlation toolkit); and
  3. a set of contributed codes built on these core products.

Download the GISMO toolbox



The Waveform Suite written and maintained by Celso Reyes

The waveform object is designed to allow easy data retrieval from a variety of sources and to make basic waveform research quick and easy. It is a toolkit that allows the creation of more sophisticated programs without having to be concerned with all details. Features include: Screenshot
  • Use any regularly sampled data stream
  • Mathematical functions: +, -, /, .*, .^
  • Standard manipulations: filter, crop, subset, subset, stack, normalize, automatic gain control, demean, detrend, taper, etc.
  • Statistics: max, min, mean, median, etc.
  • Waveform operations: hilbert transform, integration and differentiation
  • Operate on single waveforms or thousands
  • History feature tracks changes to your waveforms
  • Plotting tools for all included data types
  • Object architecture provides a stable base for writing more complex programs

The waveform suite was written and tested in Matlab release 2006b. Data can be imported from Antelope databases (requires the BRTT Antelope toolbox), Winston databases, SAC and Seisan files. With minimal coding, most any homegrown Matlab format can take advantage of the waveform architecture.

The waveform object:

  • makes playing with data easier by automating the tedious aspects of data manipulation
  • makes programs more stable by ensuring proper data typing
  • makes code more portable by reading multiple formats and functioning on multiple systems
  • makes troubleshooting faster by providing more detailed messages and warnings
Browse extensive waveform tutorial and matlab object primer

Note that the waveform suite used to be distributed as a stand alone product on Matlab File Exchange, but is now only maintained, developed and distributed part of GISMO.


The Correlation Toolkit written by Michael West

This toolkit provides an environment for analyzing waveforms with cross-correlation techniques based on a common data object. Features include:

Screenshot
  • Optimized cross-correlation routines capable of handling thousands of traces at a time
  • Max correlation and lag time determinations for all event pairs (no "master" events)
  • Dendrogram-type heirarchical clustering of event families
  • Plotting tools for all included data types
  • Suite of basic manipulation tools: filter, crop, subset, stack, normalize, automatic gain control, etc.
  • Functions for waveform interferometry
  • Optimized differential arrival times following Vandecar and Crosson, 1990
  • Built on the waveform suite

The correlation toolkit was written and tested in Matlab release 2007b. Most functionality should exist with versions 2006 and later. A few features of the correlation toolkit require the statistics toolbox (linkage, cluster and dedrogram plotting). Because data handling is carried out using the waveform suite, data can be imported from Antelope databases, Winston databases, SAC and Seisan files. There is also an import routine for the CORAL format. Since it uses the waveform suite, any homegrown format can be imported with limited coding.

See correlation toolkit cookbook for demo of utilities.
Presentation "Tools and techniques in seismic waveform correlation", March 28, 2008 (5 Mb .pdf)