Similarities and Differences of Engineering Geological Factors in the Marine Coastal Areas of the Continental United States

Abstract

The three major marine coastal zones of the continental United States (East, West, and Gulf) have many similar engineering geological characteristics, but there are critical differences. The western zone is topographically abrupt, often between young, tectonically active, rugged mountains and the ocean. The interfaces along the East and Gulf coasts generally are low, broad, coastal plains. Landward of these plains, the topographic barriers are geologically old, subdued mountain regions. Major coastal currents along the West Coast transport colder water from the north to the south. Along the East Coast, ocean circulation carries warm water from the south to the north. Major storms which influence the coastal topography generally arrive from the south along the East and Gulf coasts and from the northwest along the West Coast. Numerous submarine canyons along the West Coast are major sediment sinks for material in longshore transport. The East Coast has been developing industrially for approximately 350 years, the West Coast for about half that period. The population growth in much of the East has slowed compared to the West and Gulf coasts. Political units (states and counties) along the coasts differ in number, size, and attitudes about coastal problems. The search for and development of resources (petroleum, ocean floor minerals, power plant sites, etc.) is more intense along the Gulf and West coasts as is the associated potential for damage to the environment. A great concentration of engineering geologists exists along the coasts of the United States in particular along the West Coast. Many of the geologically related problems appear similar in these three coastal areas, but the causes and the required mitigating techniques often are unique because of their specific geographic and geologic setting.