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Plate-scale Geodynamics

Lithospheric movements and interactions at plate boundaries at or beneath the seafloor are responsible for short-term events such as earthquakes, tsunamis, and volcanic eruptions. These tectonically active regions are also host to the densest hydrothermal and biological activity in the ocean basins. The degrees to which active plate boundaries influence the ocean from a physical, chemical, and biological perspective are largely unexplored. The persistent plate-scale sensors of the OOI provide extensive scientific data about plate deformation and its causes and effects. The OOI provides a network of seismographs capable of understanding plate interactions and Earth’s deep structure and geodynamics. The permanence, power, and bandwidth associated with this network will provide critical data that cannot be economically obtained using other approaches.

The Cabled Array enables real-time measurement of seismogenic displacement across an entire tectonic plate and the ramification of these events on interlinked and temporally variable processes (e.g. crustal hydrology, volatile and thermal output from vents, methane hydrate release). Multiple frequency data enables the constraint of temporal and spatial variations in stress propagation, the styles and causes of intra-plate deformation, and its relation to plate boundary failure and ultimately the coupling of forces across plate boundaries that controls site-specific phenomena and regional-scale tectonics.

By monitoring radiated energy over the full seismic spectrum, new discoveries will likely be made of unknown signals, much in the same way that land-based networks have recently discovered episodic-tremor-and slip phenomena (so called silent earthquakes) along the megathrusts in Japan and along the Cascadia margin of North America. Infrastructure at the Axial Seamount and Hydrate Ridge, will enable the acceleration of studies concerning the structure and evolution of the lithosphere-asthenosphere system by providing new opportunities to image the deep and shallow structure of plate formation, evolution and subduction. Additionally, real-time communication provided by the Cabled Array to other sensor arrays that will allow rapid response to these events is likely to provide even more exciting discoveries.

Related Science Questions

  • What are the forces acting on plates and plate boundaries that give rise to local and regional deformation and what is the relation between the localization of deformation and the physical structure of the coupled asthenosphere-lithosphere system?
  • What is the style of deformation along plate boundaries?
  • What are the boundary forces on the Juan de Fuca Plate and how do the plate boundaries interact?
  • What are the causes and styles of intra-plate deformation?
  • What is the return flow from the ridge to the trench?
  • How much oceanic mantle moves with and is coupled to the surface plate?
  • How and why do stresses vary with time across a plate system?