Check with your data provider? Some announcement re payrolls, unemployment? Change in interest rates?
I don't normally have the volume switched on to conserve space for other things on my screen, however, a quick check and I don't get any spikes. Course the other reason that I don't have it on is that it seems unreliable at times so wouldn't go by my observations.
Sorry I can't offer any views.
One thought going through my mind though and that is you are using a very short period of data and certainly not from the start of a major wave. I would take any results you are getting with a very big pinch of salt. I would do my analysis from the 11th October 2002 low personally.