Biogeochemistry Geology

Using satellites to find underwater volcanic eruptions


Paper: O’Malley, R.T., Behrenfeld, M.J., Westberry, T.K., Milligan, A.J., Reese, D.C., Halsey, K.H., 2014. Improbability mapping: A metric for satellite-detection of submarine volcanic eruptions. Remote Sensing of Environment 140: 596-603.

The purpose of this study was to create a new metric for detecting submarine volcanic eruptions using satellite data.

Satellites can detect color changes in surface water, and therefore, are regularly used to observe phytoplankton populations living in the surface mixed layer of the ocean. Variations observed through satellite remote sensing of ocean color are responsive to nutrient delivery through a variety of water transport processes. Some examples of the processes that can move nutrients include Ekman transport, eddy-driven vertical transport, deep ocean currents and tidal pumping around seamounts and small islands.

When a submarine volcano erupts, there is an injection of nutrients into the water column that can result in a positive impact on the phytoplankton population. When heated, buoyant water from the volcanic activity rises towards the surface, it causes mixing and transport of nutrient rich water from below the surface mixed layer.

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Looking at two shallow eruptions (<40m) and three deep eruptions (130-185m), the team applied multivariate probability analysis to changes in global satellite ocean phytoplankton and particulate backscatter data. Evaluating both the “before eruption” and “after eruption” ocean color, the authors showed the correlation between eruptions, influx of nutrients, and resulting biologic activity. The results allowed creation of a reliable metric for detecting changes on the sea surface, proving the potentially robust method for detecting submarine volcanic events in remote locations.  Essentially, using standard ocean color products from satellites about phytoplankton blooms, the authors were able to make a connection to submarine volcanism.

The new metric the authors created has the potential to allow scientists to know about eruptions in remote parts of the world’s oceans. These places could then be prioritized as regions for more in depth investigation in order to gain a better understanding of how volcanism works underwater in different tectonic environments.



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