Vertical component verification

This page documents our efforts to verify that the vertical component codes are working correctly.

Code status

The JBSim3D codes and the SGT codes contain provisions for calculating Z-component SGTs and seismograms. As part of our migration from RWG to AWP for producing SGTs, we went through an extensive code comparison process, which identified that Z component SGTs must be multiplied by two when being converted from AWP to RWG format. This is, according to emails with Rob, "to account for the free-surface effect for the Z component force. In AWP-ODC I believe the Z-component is located at the free-surface whereas the X & Y components are ½ grid above/below. In my code the free-surface is coincident with the X & Y components, and Z is ½ grid above/below (I apply the factor of 2 free-surface scaling to the X & Y forces within the FD code)."