Well since the author did not talk to Google we will not find out by reading this article.
"we removed most of the gulf islands, part of BC, Washington, Oregon, and California" ...
Vs. "we removed Naples, and most other south-central Italian cities, due to the recent VEI 8 eruption of the Campe Flegree caldera complex...".
a subduction zone quake in the PNW is already overdue (they appear to happen regularly with a periodicity of 3-600 years). The famous Atlantic article from several years ago made it clear that it can be expected at any time now.