2015 Axial Seamount Eruption

Most of the volcanic activity on the planet occurs under the ocean. However, more often than not, no one notices these volcanic eruptions as they usually occur miles below the sea surface. Historically, in order to capture a live eruption, scientists had to find themselves in the right place at the right time. On April 24, 2015, however, the Axial Seamount volcano erupted and we saw it in real-time through the OOI Regional Cabled Array, making this the first undersea volcanic eruption ever recorded by an in situ cabled observatory. Over the course of a 24-hour period, several Cabled Array instruments detected ~8,000 earthquakes and a seafloor drop of 2.4 m.

The data within this nugget are from a bottom pressure and tilt sensor deployed on the Axial Seamount. The drop in the seafloor can be observed in these pressure data as the pressure exerted on the sensor (and seafloor) is increased from the extra weight of water in the overlying water column as the seafloor falls.

This drop in the seafloor or “deflation” occurs rapidly during an eruption and is caused by the ejection of magma into the ocean. Between eruptions, the magma is recharged causing the sea floor to slowly rise up again, a process referred to as inflation. Scientists have observed that eruptions at the Axial volcano occur when an inflation threshold (i.e. seafloor height) is reached making it possible to potentially predict future eruptions. You can read more about their work in the Related Publications Section and see much of the data and forecasts in the list of Additional Resources.

Changes in bottom pressure during the 2015 volcanic eruption. The seafloor drops 2.4m as the volcano erupts (an increase in bottom pressure). Note that for the purposes of clearly showing the drop in seafloor the seafloor pressure axis has been reversed. Daily fluctuations in bottom pressure are a result of the tidal cycle.

Access the Data

Disclaimer: data used in this example and provided in the .csv file were downloaded from the OOI on Aug 19, 2019. The file format and/or contents could have changed if downloaded directly from OOI Net after this date.

Access from OOI Net:

Pull Data Using Python Code. Code demonstrates how to download Bottom Pressure and Tilt data from the OOI system using the Machine-to-Machine (M2M) interface and export the data as a .csv file.

Bottom Pressure and Tilt Sensor Data Review

Cabled Axial Seamount Central Caldera (RS03CCAL)

Location: North central portion of the Axial Seamount caldera on the Juan de Fuca plate in the NE Pacific
Lat/Lon: 45.9549°N, 130.0089°W
Water Column Depth: 1,523m
Platform: Medium-Power Junction Box
Instruments: Bottom Pressure and Tilt (BOTPT-A) – connected to Medium Power Junction Box through an extension cable

Essentials of Oceanography Textbook Sections

2.2 What evidence supports plate tectonics?
2.3 What features occur at plate boundaries?
2.4 Testing the model: how can plate tectonics be used as a working model?

For more details, check out the full “Textbook Crosswalk”

Next Gen Science Standard Connections

HS-ESS2-1. Develop a model to illustrate how Earth’s internal and surface processes operate at different spatial and temporal scales to form continental and ocean-floor features. This dataset illustrates a shift in the seafloor due to a volcanic eruption on the Axial Seamount, providing an example of the constructive force of a volcano.

Additional Resources

Plots and forecasts created using OOI data by the NOAA PMEL Earth-Ocean Interactions Program:

Smithsonian Global Volcanism Program – Axial Seamount

Popular Press Articles:

OOI Science Theme

Plate-scale Geodynamics

Related Publications

Levy, S., et al. 2018. Mechanics of fault reactivation before, during, and after the 2015 eruption of Axial Seamount. Geology 46(5):447–450. https://doi.org/10.1130/G39978.1.

Spietz, R.L., et al. 2018. Deep-sea volcanic eruptions create unique chemical and biological linkages between the subsurface lithosphere and the oceanic hydrosphere. Oceanography 31(1):128–135. https://doi.org/10.5670/oceanog.2018.120.

Wilcock, W.S.D., et al. 2018. The recent volcanic history of Axial Seamount: Geophysical insights into past eruption dynamics with an eye toward enhanced observations of future eruptions. Oceanography 31(1):114–123. https://doi.org/10.5670/oceanog.2018.117.

Caplan‐Auerbach, J., et al. 2017. Explosive processes during the 2015 eruption of Axial Seamount, as recorded by seafloor hydrophones. Geochemistry, Geophysics, Geosystems 18(4):1761-1774. https://doi.org/10.1002/2016GC006734.

Kelley, D. 2017. Vulcan rule beneath the sea. Nature Geoscience 10:251–253. https://doi.org/10.1038/ngeo2929.

Nooner, S.L., and W.W. Chadwick. 2016. Inflation-predictable behavior and co-eruption deformation at Axial Seamount. Science 354(6318):1399-1403. https://doi.org/10.1126/science.aah4666.

Sigmundsson. F. 2016. New insights into magma plumbing along rift systems from detailed observations of eruptive behavior at Axial volcano. Geophysical Research Letters 43(24):12,423-12,427. https://doi.org/10.1002/2016GL071884.

Wilcock, W.S.D., et al. 2016. Seismic constraints on caldera dynamics from the 2015 Axial Seamount eruption. Science 354(6318):1395-1399. https://doi.org/10.1126/science.aah5563.