Precursors to Eruption at Axial Seamount Found

Three papers published in the journal Nature Geoscience present recent results about the 2011 eruption at Axial Seamount, and two of the three were written by NOAA Vents scientists Bill Chadwick and Bob Dziak. One paper describes the inflation/deflation cycle of the volcano leading up to and during the eruption. A second paper reports on the pattern of earthquakes before and during the eruption recorded by ocean bottom hydrophones. The third paper by colleagues at MBARI reveals the 2011 lava flows in remarkable detail, based on comparison of high-resolution mapping before and after the eruption. The journal also published a "News and Views" article describing the significance of the three papers.

Both the inflation and hydrophone recordings showed long-term and short-term precursors to the 2011 eruption that could be used to forecast future eruptions at Axial Seamount. This is particularly important because Axial will soon be the site of a cabled observatory, as part of the Ocean Observatories Initiative, that will make realtime monitoring of the volcano possible for the first time. NOAA Vents scientist are designing and building some of the instruments that will be placed on the cable at Axial.

Eruption Discovered at Axial Volcano
NOAA Vents Program scientists have discovered a newly erupted lava flow at Axial Seamount, an active submarine volcano on the Juan de Fuca Ridge located about 250 miles off the coast of Oregon.  Axial Seamount has been the site of NOAA’s New Millennium Observatory (NeMO) seafloor observatory for the past 14 years and it is the site of a future cabled observatory as part of the National Science Foundation’s Ocean Observatory Initiative (OOI).

Bill Chadwick stands next to the remotely operated vehicle Jason on the deck of the research vessel Atlantis after the dive that discovered the new lava flow on the seafloor at Axial Seamount. (Photo credit: Scott Nooner, Columbia University)

Dr. Bill Chadwick, an Oregon State University scientist with the Cooperative Institute for Marine Resource Studies along with Dr. Dave Butterfield, a University of Washington scientist with the Joint Institute for the Study of the Atmosphere and Oceans, made the discovery aboard the R/V Atlantis with the Jason remotely operated vehicle (ROV), on an expedition jointly funded by NOAA and the National Science Foundation.

A Jason dive on July 28 discovered a new lava flow on the seafloor that was not there a year ago, and bottom pressure recording and ocean bottom hydrophone instruments recovered show that the eruption occurred on April 6, 2011. The last eruption at Axial Seamount occurred 13 years ago in 1998.

Dr. Chadwick and colleague Scott Nooner from Columbia University had forecast an eruption at Axial Seamount before 2014, based on time-series measurements of volcanic inflation using bottom pressure measurements.  This is the first time that a successful eruption forecast has ever been made for a submarine volcano, and confirms that Axial Seamount is an excellent location for state-of-the-art studies of active submarine volcanic processes and how they impact ocean physical, chemical, and biological environments.

For more information on the history of Axial Volcano and NeMO please visit: http://www.pmel.noaa.gov/vents/nemo/

Images from the discovery expedition:

	New_lava_contact.jpg (.4 MB) The manipulator arm of the Jason remotely operated vehicle (upper left) prepares to sample the new lava flow that was erupted last April on the seafloor at Axial Seamount. (Photo credit: Bill Chadwick, Oregon State University, Copyright Woods Hole Oceanographic Institution).
	OBH_buried.jpg (.4 MB) The chain above an ocean-bottom hydrophone (OBH) come directly out of the seafloor where the April 2011 lava flow has buried the instrument to a depth of about 2 meters (6 feet).  The front of the Jason remotely operated vehicle is in the lower right and its manipulator arms are visible in the upper left and right. (Photo credit: Bill Chadwick, Oregon State University, Copyright Woods Hole Oceanographic Institution)
	OBH_unburied.jpg (.15 MB) A spider crab inspects an ocean-bottom hydrophone (OBH) mooring as it sits on the seafloor at Axial Seamount before the 2011 eruption.  The OBH is in the white pressure case and is a monitoring instrument designed to detect undersea earthquakes.  The chain attached to the yellow pressure case (an acoustic release) is connected to flotation above this view. (Photo credit: Bill Chadwick, Oregon State University).
	Pressure_measurement.jpg (.2 MB) The manipulator arm of the Jason remotely operated vehicle places the precise pressure sensor (yellow cylinder at left) on a cement monument that was used to measure volcanic inflation and forecast the 2011 eruption at Axial Seamount. (Photo credit: Bill Chadwick, Oregon State University, Copyright Woods Hole Oceanographic Institution)