On the Coast: Impact of Geologic Activity on Coastal Zones
Exposure to varying amounts of geologic activity is one of the major reasons why each of the United States coastal zones is so distinct.
On the Coast: Living with Erosion and Sea Level Rise
While the Atlantic and Gulf coasts are considered to be relatively gentle coastlines, erosional problems can pose problems in these areas, just as they do on the west coast. In Massachusetts, for example, the combination..
On the Coast: Protecting the Coastal Environment
Given the extensive use of the coast by humans, the task of protecting the coastal environment is enormously challenging.
Over the Edge: Continental Margins
The continental margin is the submerged outer edge of a continent. Comprised of granitic crust, the continental margin includes the continental shelf and continental slope.
Over the Edge: Deep Ocean Floor, The
Although it comprises more than half of Earth's surface area, the deep ocean floor was a region of near total mystery until fairly recently. Even now, efforts to map ocean basins are in their infancy.
Over the Edge: Exploring the Deep Ocean Floor
Scientists have made great progress in their efforts to map the deepest parts of the ocean. But even with all the new technology that's available, our knowledge and understanding of the deep ocean is far from complete. I..
Over the Edge: Hydrothermal Vents
Hydrothermal vents were discovered in 1977. They are sometimes characterized as deep ocean hot springs found thousands of feet beneath the surface. Hydrothermal vents are of great interest because of their circulation pr..
Over the Edge: Oceanic Ridge System, The
Perhaps the most striking feature that characterizes the deep ocean floor is the vast oceanic ridge system that encircles the Earth along tectonic plate boundaries.
Over the Edge: Submarine Canyons
A submarine canyon is a steep, V-shaped valley that cuts across the edge of the continental shelf and slope. It acts as a funnel, carrying sediment down to the abyssal plain.
Over the Edge: Undersea Volcanic and Tectonic Activity
For large stretches the deep ocean basin is flat. But seamounts, guyots, island arcs and trenches, all of which result at least in part from tectonic activity, break up the sameness.