Alright
Here are the images I was gonna use, measuring Ke-Pa's head (you can see it in the first image, under the yin yang symbol) based on Po's height (6'2" or 187.96 cm) and from that the crater's diameter and the depth (with the second image).
Simple craters are relatively small with depth-to-diameter ratios of about 1:5 to 1:7 and a smooth bowl shape, so I'd recommend using 1:6 if the second image isn't good enough to find the crater's depth. I was gonna use
this calculator since that site's pretty good and has a lot of shapes. Also, since only a few small chunks of the jade palace remained, I'm gonna say the crater was done with either pulverization or vaporization. There are no chunks of earth or rock anywhere.