Fit Window

The Fit Window allows you to try to use the arrival times of diffraction hyperbolae to estimate the velocity structure around the diffractors. The window displays the picked arrivals for the diffractor specified in the pop-up menu at lower right. The diffraction times should be linear on this plot if the point over the diffractor is entered in the "X center" edit field at the lower left. Clicking on the Invert Times button will cause the line shown to be fit through the points as best as possible. This line can be adjusted by clicking on it and either moving the handles at either end or dragging the line. When the cursor is over a line, the two-way travel time and RMS velocity for that line will be shown near the bottom of the window. Other diffractors' times can be fit by changing the pop-up at lower right.

Once a set of fits are found for the diffractors, clicking on the Invert Picks button in the Model Window will update the model with an estimate of the best velocity structure and diffractor depth.