Posts Tagged ‘Bill Chadwick’
Off We Go – Will Axial Seamount Surprise Us?
– Deborah Kelley, School of Oceanography Director at UW & Principal Investigator, OOI
The UW Regional Cabled Array team from the School of Oceanography and the Applied Physics Laboratory will once again have an exciting summer in the NE Pacific maintaining the National Science Foundations’ Regional Cabled Array (RCA) underwater observatory. This summer’s 37-day expedition (August 6-September 11) is especially exciting because we will be spending significant time directly viewing the highly active submarine volcano off our coast ‘Axial Seamount’, which erupted in 2015 and is poised to erupt anytime between now and sometime in 2025 (see Dr. Bill Chadwick’s blog).
The volcano, >300 miles offshore Oregon and Washington and nearly 1 mile beneath the ocean’s surface, has woken up over the past three months. Over 1000 earthquakes occurred in a single day in April and this week daily numbers are spiking at several hundred events each day (e.g >600 July 23)(see Dr. William Wilcock’s earthquake catalogue). Over this same period, the summit of the volcano began inflating at a more rapid rate as melt migrates into the shallow magma reservoir beneath the volcano. The summit of the volcano has already reached the depth it was at when it erupted in 1998 and 2011 and is approaching that of the 2015 eruption. That eruption resulted in a >400 ft thick lava flow (equivalent to ~ 2/3 up the height of Seattle’s Space Needle) and detection of over 30,000 explosions as the lava issued onto the seafloor. Temperatures in the underwater hot springs we will be visiting during the cruise are also rising — all pointing towards an immanent eruption.
The cruise will use the remotely operated vehicle (ROV) Jason and the global class research ship the R/V Atlantis operated by Woods Hole Oceanographic Institution. Excitement is building as our equipment is fully tested, safely packed away, and next week on its way via numerous 48 ft-long trucks to Newport, Oregon where we will begin mobilizing the ship starting August 6th. We are very much looking forward to working with 26 US and international students who are joining us on the expedition, working side-by-side scientists, engineers, and the ship and ROV teams.
This cruise is highly complex including berthing for 72 RCA folks during the three Legs of the cruise. A diverse array of >100 instruments, seafloor substations (junction boxes), and instrumented pods on the Shallow Profiler Moorings will be recovered and reinstalled, and tested. The cruise will also include turning instrumented vehicles on Deep Profiler Moorings. The vehicles make daily trips spanning up to ~18,000 ft as they traverse from the near seafloor environment to ~ 300 ft beneath the ocean’s surface.
The ship will be “packed to the gills” on each of the three legs that make up this expedition, carrying everything from state-of-the-art mooring components to sharpies. In addition to the core Ocean Observatories Initiative (OOI) work, seven days of the cruise will be dedicated to special programs funded by NSF to research scientists that involve turning of specialized instruments on the cable, recovery instruments and sampling of methane seeps at Southern Hydrate Ridge, and sampling of hydrothermal fluids for shore-based investigation of microbes and viruses in the extreme environments at Axial Seamount.
You will be able to watch our underwater operations live through streaming video as the ROV Jason works 1) 5000 ft down at the summit of Axial Seamount where we will see astounding seascapes of lava and numerous deep-sea active hot spring deposits that are home to some of the most bizarre creatures on Earth; 2) offshore Newport, Oregon to depths of ~250 ft to 10,000 ft in some of the most biologically productive waters in the oceans; and 3) sedimented sites on the Cascadia margin where methane-rich plumes jet from the seafloor. Here, methane seeps support dense bacterial mats and giant clams that thrive in the absence of sunlight on gases migrating through the seafloor.
An enhanced, high-bandwidth satellite connection from the R/V Atlantis will allow you to experience in real-time our deep-sea operations through live video streams to shore and onto this website.
The satellite feeds will allow scientists onboard to see data as new instruments are connected to the seafloor submarine fiber optic cables that bring the Internet into the ocean. During the cruise, engineers from the Applied Physics Lab will utilize the RCA operations center in the School of Oceanography where they will communicate directly with the instruments as they are installed, turn power on and off, and command and control instruments from hundreds of miles away and far offshore (including a resident cabled high definition camera that streams video live of an underwater hot spring at the summit of from Axial Seamount throughout the year). All total, the system hosts 150 instruments that stream data at the speed of light in real-time to shore 24/7, where they are stored and visualized through the OOI Cyberinfrastructure system at Oregon State University.
As always, it will be great to be away from the dock, smell the salt air again, and work beneath the waves on some of the most advanced technology in the oceans. For many students, these expeditions have changed their lives.
Read MoreIs Axial Seamount Napping?
Oregon State University Researcher Bill Chadwick attempted to answer this question in a poster he presented at AGU in December 2023. Chadwick has been watching the “ups and downs” of Axial Seamount for more than 30 years, including its last eruption in 2015. He and other observers monitor the seamount’s activity using bottom pressure recorders (BPR) connected to the US National Science Foundation Ocean Observatories Initiative (NSF OOI) Regional Cabled Array (RCA), operated by the University of Washington, along with additional uncabled BPRs and Mobile Pressure Recorder surveys at an array of seafloor benchmarks every two years using a remotely operated vehicle.
[media-caption path="https://oceanobservatories.org/wp-content/uploads/2024/03/BPR-scaled.jpg" link="#"]A repeatable inflation-deflation cycle has been documented at Axial Seamount over the last 30 years, using autonomous, battery-powered Bottom Pressure Recorders (BPRs), and later cabled-BPRs like this one connected to the OOI-RCA. Credit: UW/NSF-OOI/CSSF, 2014.[/media-caption]“Axial Seamount has erupted three times in the last 25 years. As of March 2024, the seamount is 90-95% reinflated to the level it reached before the 2015 eruption, so we’re getting close to the eruption triggering point,” said Chadwick. “But on the other hand, the rate of inflation, which started high right after the 2015 eruption, has been decreasing and decreasing since then.”
The inflation rate reached nearly zero last summer (just slightly positive at ~1 cm/year, the lowest rate seen at Axial). “At that very low rate, it was hard to tell how long it would take to reach the 2015 inflation threshold,” Chadwick added.
Since October 2023, however, the rate of uplift has been slowly increasing. University of Washington Researcher William Wilcock’s Axial Seamount Earthquake Catalog page also indicates the seismicity has been on the rise since October 2023, with a large swarm of >600 events on 10 February.
“Since October 2023, the rate of inflation has increased a bit to 5-6 cm/yr, which is still quite low compared to rates we’ve seen over the last 25 years but seems to indicate that Axial may be coming out of its slumber of last summer,” Chadwick explained. “And the earthquake swarm on Feb 10 also seems to support that notion.”
Longer-term eruptive history documented by mapping and dating lava flows at the summit shows that Axial has produced at least 50 eruptions in the last 800 years, (Clague et al., 2013), an average of one every 15-18 years, suggesting that the current lull at Axial might not be long.
“I’m hoping that the rate of inflation will continue to increase, but it’s too early to tell. Anything could happen,“ Chadwick added. “I’m more hopeful than I was a year ago that the next eruption may not be too far off but only time will tell!”
[media-caption path="https://oceanobservatories.org/wp-content/uploads/2024/03/Chadwick-dots.jpg" link="#"]Map showing the locations of Mobile Pressure Recorder (MPR) benchmarks, as well as the autonomous and cabled Bottom Pressure Recorders (BPR). The red dots are the BPRs connected to OOI Regional Cabled Array.[/media-caption]
Reference: Clague, D.A., et al., (2013) Geologic history of the summit of Axial Seamount, Juan de Fuca Ridge, Geochem Geophys, Geosystems, doi: 10.1002/ggge.20240.
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