Deep Pacific swells hint at looming upheaval.

Off the Oregon coast, hidden beneath more than a mile of seawater, the Axial Seamount is stirring with a troubling intensity. Scientists are detecting earthquake swarms, inflation of the seafloor, and chemical shifts that together suggest magma is on the move. This undersea giant, sitting along the Juan de Fuca Ridge, has erupted before, but the signals this year echo and amplify what came before 1998, 2011, and 2015. Real-time observatories now beam back data every second, offering an unflinching look at a massive volcano swelling in silence, and every new tremor ratchets up the question of whether the Pacific floor is about to tear open again.



