Reply #24: Yep

[Jose Diablo]

The seismographs clearly show the airplanes crashing into the buildings long before the actual collapse.

As for the collapse itself, there is a very large spike at the very beginning and then lower amplitude spikes as the buildings come down.

I think somebody explained the huge initial spike as a "S" wave, surface wave, that conducts through the surface easier. Then the others as deeper waves. I don't know it this was true, but the are clear very large initial spikes right at the beginning of the collapses.

Pictures of the seismographs can be downloaded.