Continental margins are the area of the seafloor where the continental shelf transitions to the abyssal plain. This dynamic region of the seafloor is modified by geologic processes both slowly, over long periods of time, as well as abruptly, in discrete events. These include erosion, transport and deposition of sediments by currents; tectonic deformation; and discharge of submarine groundwater.

The impact of the slow, steady on-going processes has historically been inferred from the seafloor morphology and the nature of the underlying strata. However, there are also turbidity currents, submarine landslides, earthquake ruptures and tsunamis that cause extremely rapid changes to the seafloor. Such events constitute significant marine geohazards and understanding their recurrence rates are of societal importance. We investigate how the morphology of the seafloor here is sculpted and changed over time.

Perspective views of 1 m resolution bathymetry collected with MBARI’s mapping AUVs showing three unique morphologies that provide insight into the sedimentary processes occurring on the seafloor.

Technological advances over the last few decades have allowed us to collect extremely high-resolution maps, make direct visual observations, monitor turbidity currents in real time, and surgically sample event deposits. These techniques allow the rates and dynamics of these processes to be quantified in ways that were previously impossible. Of particular benefit is the ability to conduct repeated high-resolution mapping surveys which directly quantifies seabed changes over known time periods.

Our present focus is on distinguishing the relative importance of slow versus rapid changes in four areas: submarine canyons and channels, permafrost under the Arctic shelf, pockmarks, and seafloor fault deformation.

The impact of the slow, steady on-going processes has historically been inferred from the seafloor morphology and the nature of the underlying strata. However, there are also turbidity currents, submarine landslides, earthquake ruptures and tsunamis that cause extremely rapid changes to the seafloor. Such events constitute significant marine geohazards and understanding their recurrence rates are of societal importance. We investigate how the morphology of the seafloor here is sculpted and changed over time.

Know Your Ocean

Monterey Canyon

Monterey Canyon brings the deep sea close to shore. Studying this underwater canyon helps us understand the dynamic processes in the largest environment on Earth.

Publications

Paull, C. K., J. K. Hong, D. W. Caress, R. Gwiazda, H. Kim, E. Lundsten, J. B. Paduan, Y. K. Jin, M. J. Duchesne, T. S. Rhee, V. Brake, J., Obelcz, and M.A.L. Walton. 2024. Massive Ice Outcrops and Thermokarst Along the Arctic Shelf Edge: By-Products of Ongoing Groundwater Freezing and Thawing in the Sub-Surface. Journal of Geophysical Research: Earth Surface, 129(10). https://doi.org/10.1029/2024JF007719

Kang, S.E., Y.K. Jin, U. Jang, M.J. Duchesne, C. Shin, S. Kim, M. Riedel, S.R. Dallimore, C.K. Paull, Y. Choi, and J.K. Hong. 2021. Imaging the P-wave velocity structure of Arctic subsea permafrost using Laplace-domain full-waveform inversion. JGR Earth Surface, 126: 1–15. https://doi.org/10.1029/2020JF005941

Paull, C.K., S.R. Dallimore, Y.K. Jin, D.W. Caress, E. Lundsten, R. Gwiazda, K. Anderson, J.H. Clarke, C. Youngblut, and H. Melling. 2022. Rapid seafloor changes associated with the degradation of Arctic submarine permafrost. Proceedings of the National Academy of Sciences, 119: 1–8. https://doi.org/10.1073/pnas.2119105119

Gwiazda, R., C.K. Paull, B. Kieft, D. Klimov, R. Herlien, E. Lundsten, M. McCann, M.J. Cartigny, A. Hamilton, J. Xu, K.L. Maier, D.R. Parsons, and P.J. Talling. 2022. Near-bed structure of sediment gravity flows measured by motion-sensing “boulder-like” Benthic Event Detectors (BEDs) in Monterey Canyon. Journal of Geophysical Research: Earth Surface, 127: 1–22. https://doi.org/10.1029/2021JF006437

Lee, D.H., J.H. Kim, Y.M. Lee, J.H. Kim, Y.K. Jin, C. Paull, J.S. Ryu, and K.H. Shin. 2021. Geochemical and microbial signatures of siboglinid tubeworm habitats at an active mud volcano in the Canadian Beaufort Sea. Frontiers in Marine Science, 8: 1–16. https://doi.org/10.3389/fmars.2021.656171

Technologies