The volcano is located about 250 miles off the coast of Oregon, and a series of recent quakes and seafloor movements have been picked up by instruments at the site starting on April 24, 2015. None of the activity was strong enough to create a tsunami or even be felt on land however. This series of movements was accurately predicted in the fall of 2014 when experts forecast that an eruption would occur within the next 15 months.
(Source: NOAA, University Of Oregon, video from USA Today)