Once overlooked because of its relative inactivity compared to other subduction zones around the world, the Cascadia Subduction Zone (CSZ) — and the potentially devastating megathrust earthquakes and tsunamis it could unleash — are today well known to both geoscientists and the public. Beginning with the efforts of John Adams of the Geological Survey of Canada and Brian Atwater of the U.S. Geological Survey in the late 1980s, a series of oceanic research cruises and datasets has steadily advanced our understanding of Cascadia. It seems like there is “a paradigm change every few years,” says Chris Goldfinger, a geologist at...