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What's New Archive

October 29, 2018

Results of the research documenting a recent volcanic eruption on the Mariana back-arc, 4500 meters deep, (making it the deepest known eruption on Earth) were published this week in a special issue of Frontiers in Earth Science (23 October 2018 | It was first discovered in December of 2015 with cameras aboard an autonomous underwater vehicle, Sentry, by researchers searching for new hydrothermal vents. Bathymetric data also indicated major depth changes in the area collected between surveys in 2013 and 2015, were consistent with an eruption. The new lava flows stretched over an area about 4.5 miles long and ranged in thickness between 130 and 450 feet.  Sentry’s 2015 photos revealed the presence of a pristine dark, glassy lava flow on the seafloor with no sediment cover. Images also showed venting of milky hydrothermal vent fluid indicating the lava flow was still warm, and therefore very young. By 2016 when scientists returned to the site in April and December with remotely operated vehicles Deep Discoverer and SuBastian, the observations showed a rapidly declining hydrothermal venting on the lava flows, suggesting the eruption had taken place only months before its discovery the previous year.  These expeditions were conducted aboard the NOAA ship Okeanos Explorer and the research vessel, Falkor.

A marine geologist at NOAA’s Pacific Marine Environmental Laboratory and lead of the Earth-Ocean Interactions Program, who is lead author on the study, said “We know that most of the world’s volcanic activity actually takes place in the ocean, but most of it goes undetected and unseen.” In the last 30 years, scientists utilizing improving technology and exploration methods have detected evidence of about 40 undersea eruptions. Before 1990, there were zero. This research is important as undersea volcanoes can help inform us about how terrestrial volcanoes work and how they impact ocean chemistry, which can significantly affect local ecosystems.

The research was funded by the NOAA Office of Ocean Exploration and Research and NOAA’s Pacific Marine Environmental Laboratory, and was supported by the Schmidt Ocean Institute.

NOAA-PMEL-EOI Marianas Research:

New York Times: A Vault of Glass and the Deepest Volcanic Eruption Ever Detected
OSU Press Release: Researchers discover deepest known underwater volcanic eruption
Earther: The Deepest Volcanic Eruption Ever Documented Left a Gnarly Sight on the Ocean Floor



Image of Lost City vent
September 17, 2018

EOI scientists are participating in a deep-sea expedition to the Lost City hydrothermal vent field in September 2018. The Lost City is a beautiful seafloor formation whose unique scientific and cultural value has brought it under consideration for special protection by the UNESCO World Heritage Centre and International Union for Conservation of Nature. The Lost City is also featured in many studies on the origin of life and the search for life in the solar system. This will be the first US expedition dedicated to the Lost City since 2003-2005. 

Follow the cruise blog for daily updates at:

August 16, 2018

EOI scientists will be going out to Axial Seamount on a sea-going expedition, August 18-27, 2018. Axial is an active submarine volcano located 300 miles west of the Oregon coast. They will be making dives with ROV Jason and the MBARI Mapping AUV from the R/V Kilo Moana.

This expedition will be focused on three main areas:

1) Monitoring the inflation of the volcano caused by magma rising into the volcanic system from below between eruptions

2) The chemistry of hydrothermal vent fluids and how they change with time

3) Exploration of a new hydrothermal vent field, possibly with active black smoker chimneys, that was discovered recently with high resolution AUV bathymetric mapping.

Follow the cruise blog for daily updates at:

Methane hydrate deposit and gas
June 06, 2018

EOI scientists aboard E/V Nautilus June 12-29 used multibeam sonar and a remotely operated vehicle to more fully document and characterize the undersea methane sites from Northern California to Washington.  Up until a few years ago, only 100 methane “seep sites” had been identified primarily by fisherman using their fish-finders observing the acoustic reflections of the gas bubbles.  Beginning in 2016, EOI scientists began a more systematic mapping of the seeps using new sonar technology on the E/V Nautilus, owned and operated by the Ocean Exploration Trust.  About 25 percent of the potential methane seep water column area has now been mapped and analyzed. This year, EOI researchers embarked again on the Nautilus to continue surveying additional methane sites by night.  During the day a remotely operated vehicle (ROV) colleted samples of gas, methane hydrate, seep water, fauna and rocks at these sites.  Analyzing these samples in conjunction with a more complete inventory of sites will help scientists understand the origin of the seeping methane and its impact on the ocean environment.

More information about the Cascadia Margin expedition:

More information about the methane research and expedition can be found at:

NOAA PMEL EOI Program Methane Studies:

Oregon State University Press Release:

newly discovered hydrothermal vent from this expedition
January 04, 2018

EOI Scientists recently completed a 2-part expedition aboard R/V Falkor in the NE Lau Basin in the SW Pacific, one of the most volcanically and tectonically active parts of the planet (November 10 - December 18, 2017). Leg 1 included CTD casts and tows to locate hydrothermal plumes and the AUV Sentry made dives to collect high-resolution bathymetry. Leg 2 returned with ROV SuBastian on board to make dives at a 11 different submarine volcanoes in the area.  Findings include detecting a wide range of eruption styles, observing some of the rarest rock types on Earth, exploring the largest known dacite lava flow on our planet, and discovering three new hydrothermal venting sites. Read more about the expedition at Schmidt Ocean Institute’s web site.

SOI provided the ship and support for this expedition. Additional support is provided by NOAA Office of Ocean Exploration.

Axial Seamount in 3D

Black icons are benchmarks where pressure measurements will be made and white dots are hydrothermal vent locations.

June 26, 2017

The 2017 expedition to Axial Seamount was on R/V Revelle, July 13-23, with ROV Jason and AUV Sentry on board. On this expedition we made measurements to monitor the continued re-inflation of the volcano since its last eruption in 2015 so we can better understand how magma is supplied and stored within the volcano, how it fuels hydrothermal vents and their biological communities, and how we can refine forecasts of future eruptions.  We also sampled hydrothermal vents to continue a time-series aimed and understanding the interactions between volcanic events and the hydrothermal and biological systems.  A cruise report is in preparation and will be posted here when it is finished.

The expedition website with daily logs from July 12-23 aboard the R/V Revelle with ROV Jason and AUV Sentry is available at:

Methane Seeps - Northern Cascadia Margin
May 22, 2017

E/V Nautilus expedition NA080 leg 2 begins the evening of May 22 and continues through June 5 mapping the seafloor and water column in search of methane bubble emission sites.  This part of the Ocean Exploration Trust (OET) expedition is a continuation of work that was done last summer for PMEL Earth Ocean Interactions (EOI) Program on the Cascadia Margin, offshore Washington, Oregon, and Northern California.  2016 expeditions NA072 and NA078 resulted in the discovery of 905 individual methane bubble streams that were clustered into 317 emission sites.  The vast majority of those sites were previously unknown.   The purpose of this exploration is to establish a baseline of methane bubble emission sites and methane-derived habitat (carbonate hardground) for the Cascadia margin.  A warming ocean could disassociate some of the solid methane hydrate now locked up in the sediments along continental margins at >~ 500 m depth.  Methane is a potent greenhouse gas so there is interest in understanding what happens to the methane as it rises through the water column.  Does it make it into the atmosphere?  Does it contribute to ocean acidification?  There is also interest in the extent of the seep habitat and associated hardgrounds from the perspective of essential fisheries habitat.  Those are just a few of the questions EOI scientists are hoping to answer with this research.   You can follow the expedition here:

October 20, 2016

EOI and collaborators are the first scientists using the new Schmidt Ocean Institute’s ROV SuBastian aboard the R/V Falkor as they return to the Mariana back-arc spreading system on an expedition from November 29 to December 20.   This year's cruise follows up on discoveries made last year aboard R/V Falkor of new hydrothermal vent sites and lava flows in the Mariana back-arc.  EOI also co-directed several NOAA Ship Okeanos ROV Deep Discoverer dives this past summer yielding some additional observations in this relatively unexplored region.  ROV SuBastian will provide in-depth exploration and sampling of these systems to characterize their geologic setting, chemical environment, and biological communities.  This expedition is supported by Schmidt Ocean Institute, NOAA's Ocean Exploration and Research Program, and the NOAA Pacific Islands Regional Office. (Image courtesy of Schmidt Ocean Institute)

image of hydrothermal vent

Image courtesy of NOAA Office of Ocean Exploration and Research, 2016 Deepwater Exploration of the Marianas. 

July 29, 2016

EOI scientists participated in several ROV dives remotely via "telepresence" during the 2016 Deepwater Exploration of the Marianas expedition by the NOAA ship Okeanos Explorer.  During Leg 1 of the expedition, EOI co-led three dives in the Mariana backarc, exploring the site of a recent eruption  and two newly discovered hydrothermal vent fields. All of these discovered during a recent cruise on R/V Falkor in Nov-Dec 2015, and set the stage for further exploration during a follow-on R/V Falkor cruise in December 2016.  During Leg 3 of the Okeanos expedition, EOI co-led three dives in at three volcanically active seamounts, each with its own unique ecosystem.  The expedition was supported by the NOAA Ocean Exploration and Research Program.

Methane hydrate depost on seafloor
June 10, 2016

The Ocean Exploration Trust Inc. ship E/V Nautilus, with several NOAA-PMEL and Oregon State University CIMRS scientists aboard, is using the latest midwater sonar technology to map out methane seeps along the Cascadia continental margin this month.  PMEL/CIMRS scientists report that, after locating extensive bubble plumes of methane in Astoria canyon at 850 m, the remotely operated vehicle Hercules visited the site and found an exposure of methane hydrate and gas bubbles streaming out of the seafloor.  The hydrate, a mixed water/methane ice phase, is present over extensive areas of continental margins, but has only rarely been observed exposed at the seafloor along the Cascadia margin.  Why the hydrate is exposed at this location in association with the methane gas seepage is a topic of discussion among the scientists aboard the Nautilus and those ashore participating remotely via the internet.   The E/V Nautilus is a unique platform with extensive telepresence capability that enables scientist aboard to interact with those in the broader scientific community and the public ashore.  Dives with the Hercules are broadcast live over the internet and can be viewed at