Signs of underwater volcanic eruption south of B.C. coast

Tuesday, May 5, 2015, 12:37 PM - Thousands of tiny earthquakes indicate an underwater volcano is likely erupting more than 400 kilometres off the west coast of the United States.

Though nothing has been seen from the water's surface, changes at the bottom of the Pacific Ocean reveal that the most active underwater volcano in the northwest is spewing lava.

Scientists often compare activity around the Axial Seamount volcano to a balloon. The seafloor begins to rise as it fills with magma in the time leading up to an eruption, similar to an inflating balloon.

Once magma is released from the crater, the balloon 'pops;' and the seafloor 'deflates,' or falls back.

Geologists Bill Chadwick of Oregon State University and Scott Nooner of the University of North Carolina Wilmington predicted the eruption in a blog post in 2014.

Changes in temperature, seafloor elevation and thousands of tiny earthquakes last week alerted scientists to the likelihood of volcanic activity more than one kilometre under the sea.

Experts will have to physically visit the site and retrieve data from instruments located on the seafloor, in order to confirm the eruption, but most signs point to yes.

The Axial volcano is one in a string of volcanoes along the Juan de Fuga Ridge, a tectonic plate boundary that stretches along the western coastline from Oregon up to B.C.

The underwater mountain rises 900 metres up from the ocean floor. 

The volcano has erupted twice in the last fifteen years, most recently in 2011.

Though the recent activity has experts excited, it poses no danger to people living along the coast. Changes in the sea beds and lava flow are too slow to trigger a tsunami, and the multiple quakes are too small to cause any damage.

Axial Seamount is a very active spot for researchers. In addition to volcanic eruptions, hydrothermal vents throughout the area contribute to a diverse ecosytem.

Source: NOAA | Livescience