The chart shows year and magnitude.
Dr. Goldfinger (not that one, the Oregon guy) gave a presentation of these earthquakes in a video format on Thursday at an event I was at. I'll try to get a link to it, but until then, see this chart of 10,000 Years of Cascadia Earthquakes.
What was cool about the video is that is shows the segment of the earthquake fault that ripped. Some earthquakes on the fault do not go the entire length. Then the other very interesting fact depicted (in the video) is that they correlate it with San Andreas fault earthquakes.
Hopefully I'll get that link that will illuminate visually — even more than a static chart, the series of events on the fault.
Note, there was another presentation about earthquake faults in Washington state. Of course they can't predict earthquakes, but taking into account all known faults, the estimate is that we will have a significant earthquake every 190 years.
The question is — where are we in that cycle of events now?