This 7.0 preliminary may actually go up a little bit before it is all said and done. We would have to adjust the magnitude to at least 7.3 to be included in the top 15. This is what is considered a moderate earthquake. Off the top of my head, I would say this would be a little less powerful than the Northridge or Loma Prieta earthquakes in California. Both of those were in the 7.0 and above range.
Geologists have a process much like meteorologists.
After a tornado, we have to go out and do damage surveys to determine how strong the tornado was. It may be several days before we know the answer to that question. The largest earthquake in Washington was in 1872. That was a 7.4 in the northern cascades. There have been numerous 8.0 and greater earthquakes throughout this century.