A Tease for Theoretical Seismologists

Jon Claerbout

What do these pictures tell us? Do they have any relation to seismology?

Terman pool is next to my office. It is about 8 inches deep. I took this picture standing about 20 feet above it. There is a water fountain off the upper left corner. To enlarge any picture, click on it.
I took this picture at my house. The pool is 9 feet deep and I was standing alongside it. I had just climbed out of the water leaving these waves. (There are a few leaves on the water bottom.)
I found this picture in a magazine.
Go to NASA to see an explanation and enlargement of this picture. If you stretch your mind you may see some mathematical similarities with the images above. Some very distant galaxies have been turned into arcs and streaks of light because of lensing at an intermediate distance.

Please answer the questions above before reading further.

This next question is just a hint: Notice that the white lines are sharply defined. Notice that we always see these white lines regardless of the depth of the water. They seem to become vertical white lines along the side of the fish body. I can explain this. Can you?

The real questions are up at the top in the first paragraph.

I'd like to gather your comments here, but I don't know how to. If you would like to comment, please try to do it at seismicamplitudes.blogspot.com. If you know how to set up better discussion software, please give me some clues how to do it.

If you don't have anything to say about the pictures, I'll try harder to get you started. Do the photos suggest a forward problem? Do they suggest an inverse problem?