There was a download of Talwani 2.3 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. We recommend checking the downloaded files with any free antivirus. Talwani lies within Photo & Graphics Tools, more precisely 3D Design. The actual developer of the free program is PACES. The most popular versions of the program 2.3 and 1.0.
From the developer:
The Talwani software is a gravity profile forward modeling program based on the technique of Talwani et al. (1959) and Cady (1980). This version of the program runs on a PC using the Windows operating system. The model that the user constructs can consist of 2-D (infinite strike extent) or 2-1/2 dimensional bodies.
You may want to check out more software, such as 3D Studio VIZ R3, Win4D Advance or Abalone, which might be related to Talwani.