I had a discussion with a colleague today, about the likelihood of a major earthquake in California

[rjsquirrel]

5. The math cannot render that level of precision

In the scale of geologic time 40 years isn't even the blink of an eye. That various faults and the larger subduction zone are certain to shift and cause quakes can be pinpointed to within centuries in some cases, but even then it's probabilistic and depends on unknown or poorly understood variables that affect the cycles that can be observed in historical time or the geological record.

The question is thus asking for a gut feeling. No geologist will predict "the big one" with precision with any confidence on a 40 year interval. Could happen today. Could happen in 2060. From a geological perspective that's milliseconds apart.