A new version of the locator (ISCloc2.2.7), including minor bug fixes, was released in July 2025. The documentation remains the same as the previous version (ISCloc2.2.6).

Download ISCloc (68 MB).

The previous version (2.2.6), released in February 2015, remains available below

Download ISCloc (Previous Version) (42 MB).

Download ISCloc documentation (pdf).

Download registered station list (csv).

Download ISCloc Virtual Machine (844 MB).

The new ISC location algorithm became operational on January 1, 2011. The main features of the location algorithm include:

• uses of all IASPEI standard phases with a valid ak135 travel time prediction;
• obtains an initial guess for the hypocentre using the Neighbourhood Algorithm;
• tests for depth resolution before attempting for a free-depth solution;
• accounting for correlated travel time prediction errors along similar ray paths.

The ISC location algorithm can also be compiled in a way that enables the use of regional Pg, Lg, Pn and Sn travel time predictions from a 3D velocity model. The Regional Seismic Travel Time (RSTT) software package has been developed by the US DoE Lawrence Livermore, Los Alamos and Sandia National Laboratories, and it consists of a global upper mantle 3D velocity model as well as very fast ray tracing utilities through the model. The RSTT package can be downloaded from the DoE NNSA website.

We express our gratitude to Malcolm Sambridge and Brian Kennett (Australian National University) for making code of the Neighbourhood Algorithm available to us; Bob Engdahl (Colorado University at Boulder) for discussions and for providing the code for bounce point corrections; Jack Murphy and Brian Barker (Science Applications International Corp.) for the depth-phase stacking algorithm; Johannes Schweitzer (NORSAR) for discussions on the libtau software; and Steve Myers (LLNL), Sandy Ballard (Sandia), and Michael Begnaud (LANL) for discussions on the RSTT software package.

The software package comes as is; we cannot provide support or maintenance. You may freely modify the code in order to integrate it to your processing environment. If you use the ISC location algorithm, please refer to the article:

Bondar, I. and D. Storchak, 2011. Improved location procedures at the International Seismological Centre, Geophys. J. Int., 186, 1220-1244, doi: 10.1111/j.1365-246X.2011.05107.x.

Video tutorials for ISCloc Virtual Machine Implementation in Microsoft Windows environment.

1. Installation
2. Extensions Installation
3. Importing ISCloc into VirtualBox
4. Starting ISCLocator
5. USB Mass Storage usage