Hi Roger. It is my understanding that we see under normal conditions is the "coda" or the normal pulse, or movement the earth has. I think the best term I could use is that this is the normal background noise we see.

I know that whenever there is a quake the trace starts going almost straight up and down and is a lot faster then what were seeing now.

The link should take you to past quakes. The one on the Hayward fault is very close to what we saw yesterday. Take Care…Don in creepy town.

• Memento Mori