Executive Summary: Axial Seamount at a Glance

Axial Seamount is the most active submarine volcano in the northeastern Pacific, located about 300 miles off the Oregon coast on the Juan de Fuca Ridge. Due to its accessibility and frequent activity, it is one of the most intensely monitored underwater volcanoes in the world, largely through the Ocean Observatories Initiative (OOI).

Its behavior is so well-studied that scientists have successfully forecast its last three eruptions (in 1998, 2011, and 2015). The current projection is that the volcano is recharging its magma reservoir and will likely erupt again, with the next event projected for the 2020s, potentially around 2024-2025.

1. The Latest Projections & Current Status (As of Late 2023/Early 2024)

A. The Inflation-Deflation Cycle: A Predictable Pattern

Axial Seamount behaves like a “leaky bladder.” It follows a remarkably consistent cycle:

• Inflation: The magma chamber beneath the summit refills, causing the seafloor to uplift (inflate) like a balloon. This occurs in the years between eruptions.
• Deflation: When the pressure in the chamber exceeds the strength of the rock, the volcano erupts. Magma is injected into the rift zones, and the summit collapses (deflates) by several meters.
• Repeat: The cycle immediately begins again.

B. Status Since the Last Eruption (2015)

• The 2015 Eruption: The most recent eruption began on April 24, 2015. It was forecasted months in advance and detected in real-time by the OOI’s cabled observatory. The summit dropped by about 2.4 meters (almost 8 feet) as magma drained out.
• Current Phase – Re-inflation: Since the 2015 eruption, Axial has been in the inflation phase. Seafloor instruments have been meticulously tracking the re-inflation of the magma reservoir and the upward push of the seafloor.

C. The Forecast for the Next Eruption

Based on the consistent rate of inflation observed since 2015, the lead scientists monitoring Axial have published a specific forecast:

• Projected Timeline: The next eruption is expected sometime between 2020 and 2024, with a more refined estimate pointing to around 2024-2025.
• Trigger Point: The eruption is projected to occur when the seafloor deformation (inflation) returns to the level it was at just before the 2011 eruption. As of the latest published data, the volcano was about 75-80% of the way to that “eruption threshold” in 2023.
• Confidence: This is not a guarantee, but a high-confidence forecast based on a well-understood physical model. It is the volcanic equivalent of predicting high tide based on the moon’s orbit.

2. Key Monitoring Data and Recent Signals

The projections are based on real-time and near-real-time data from the OOI’s Cabled Array:

• Bottom Pressure Recorders (BPRs): These are the most critical instruments. They act like underwater “weight scales,” measuring the precise height of the seafloor. A steady increase in pressure indicates inflation; a sudden drop signals deflation (an eruption).
• Seismometers: These detect the thousands of small earthquakes that occur as the volcano inflates and the crust fractures. A rapid increase in seismicity often precedes an eruption.
• Hydrophones: These listen for the sound of earthquakes and the distinct acoustic “roar” of an eruption.
• Temperature and Chemical Sensors: These can detect hydrothermal plumes and changes in vent fluid chemistry that indicate magmatic activity.

Recent Data Trends: The data throughout 2023 showed a continuation of steady inflation and persistent, low-level seismicity, consistent with the volcano recharging and building towards its next eruption.

3. What to Expect When the Next Eruption Happens

When the next eruption occurs, the OOI network will likely detect it within minutes. The event will likely include:

• Thousands of Earthquakes: A seismic swarm as magma breaks through rock.
• Rapid Seafloor Deflation: The summit will drop by 2-3 meters (6-10 feet) over a period of days to weeks.
• Lava Flows: New lava flows will erupt along the summit and rift zones, creating fresh pillow basalts and sheet flows.
• Hydrothermal Plumes: The eruption will trigger massive “megaplumes” of hot, chemically-rich water that can be detected by sensors.
• No Tsunami Threat: Eruptions at Axial are highly unlikely to generate a significant tsunami. The eruptions are effusive (oozing lava) rather than violently explosive, and the volcano is in deep water.

Key Sources for the Very Latest Information

To get real-time data and the most up-to-date status, these are the best resources:

• Ocean Observatories Initiative (OOI) Data Portal:
  Website: https://ooinet.org/
  You can look at live data from the Axial Base Seismic Instrument and Bottom Pressure Recorders on the caldera.
• Bill Chadwick (OSU/NOAA PMEL): One of the lead volcanologists forecasting Axial’s eruptions. His blog and publications are invaluable.
  Volcano Watch Blog: https://www.pmel.noaa.gov/eoi/axial_blog.html
• Scott Nooner (University of North Carolina Wilmington): The other key scientist specializing in the seafloor deformation measurements at Axial.

Conclusion

Axial Seamount is a remarkable natural laboratory. The projection is clear: the volcano is on track for its next eruption in the mid-2020s. When it happens, it will be a spectacular event for science, documented in real-time like never before, and will provide a new benchmark for understanding submarine volcanism.