SurfSeis 5.3 was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this software available.
The default filenames for the program's installer are SurfSeis3p06.exe, SurfSeis.exe, SurfSeis3p05.exe, SurfSeis4.exe or SurfSeis5.exe etc. This program was originally developed by Kansas Geological Survey. SurfSeis belongs to Education Tools. We recommend checking the downloaded files with any free antivirus. The most popular versions of the program are 5.3, 4.2 and 4.0.
From the developer:
SurfSeis is an app that allows you to process seismic data using the multichannel analysis of surface waves (MASW) method. The Active MASW uses active seismic sources (e.g., sledgehammers, weight drop, charges, etc.) and a linear receiver array, and data collected in a roll-along manner.
You may want to check out more software, such as f x -Viewer, Pocket Stars or wxMaxima, which might be related to SurfSeis.