2015 Axial Seamount Eruption

Most of the volcanic activity on the planet occurs under the ocean. However, more often than not when these volcanic eruptions occur no one notices as they are occurring miles below the sea surface on the seafloor. To capture a live eruption, scientists historically have 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, these 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 at 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 during the eruption. 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.

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: RS03CCAL-MJ03F-05-BOTPTA301

Pull Data Using a 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

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.

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? Sea floor spreading and features of the ocean basins
2.3 What features occur at plate boundaries? Divergent boundary features
2.4 Testing the model: how can plate tectonics be used as a working model? Seamounts and tablemounts

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 to show the constructive force of a volcano in action.

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

Global Biogeochemistry and Carbon Cycling

Related Publications

Levy, S., et al. 2018. Mechanics of fault reactivation before, during, and after the 2015 eruption of Axial Seamount Geology46 (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