Earth Science Unit 5

If the wave period changes so that it is half its original value, how does this change the wavelength?

The wavelength will also be half as long.

Which statement best explains the formation of seamounts?

They represent volcanoes situated over mantle plumes that have since moved away from their source of magma and subsided.

When a headland of resistant bedrock extends out into the ocean, which statement best describes wave action in proximity to the headland?

Wave energy is focused on the headland.

How are satellites able to map the ocean floor?

Due to gravity, ocean water is attracted to areas of high topography and away from areas of low topography on the sea floor, causing bulges and depressions on the ocean surface. Satellite radar can detect these changes in elevation.

Which feature results from the collapse of a sea arch?

sea stack

An open water wave with a wavelength of 4 meters moves onshore into shallow water. At what depth does the wave begin to touch bottom?

2 meters

What is the correct water depth for an echo travel time of 6 seconds? (For the purposes of this exercise, assume pressure and temperature effects on sound wave velocity are negligible.)

4500 meters

Once hard stabilization of a coast is initiated by construction of structures such as groins and breakwaters, why is it often necessary to continue building more of these structures?

Construction of groins and breakwaters disrupts the natural flow of sediments along the coast.

Which response best explains the absence of volcanoes and earthquakes at a passive continental margin?

Earthquakes and volcanoes are rare due to the distance from any active boundaries

Which pattern of particle movement occurs when wave movement is oblique to the beach?

Particles move on the beach in a zigzag pattern.

Which situation occurs in the downcurrent direction when a groin is constructed on a beach to prevent erosion of a beach by longshore currents?

Sediment is removed on the downcurrent side of the groin

Which feature would you expect to find at the mouth of a submarine canyon?

a deep sea fan

Which process is directly responsible for the development of notches, cliffs, and platforms?

abrasion

Which pattern best describes the motion of water particles in a wave in the open ocean?

circular orbit

Moving off the east coast of North America, identify the sequence of environments you would encounter as you move deeper into the Atlantic Ocean.

continental shelf, continental slope, continental rise, abyssal plain

Which is not one of the three broad zones describing the ocean floor?

continental slope

Which method is not a technique currently used by ocean scientists to map the topography of the ocean floor?

magnetometer

Which term is used by geologists to identify the time interval between the passage of successive wave crests or troughs?

period

Which coast represents an active continental margin?

the west coast of South America

In the graph of echo sounding data that you created as part of this exercise, why is the vertical component of the graph exaggerated?

to compensate for the differences in the smaller vertical depths in the ocean relative to the greater horizontal distances measured

The deepest parts of the ocean are related to which tectonic feature?

trenches

Occasionally, when a sea stack is formed, accumulations of sand are deposited behind it, producing a tombolo. Which process is responsible for the creation of the tombolo?

wave refraction

Which term is used to define the distance between successive wave crests or troughs?

wavelength

When waves approach shore and touch bottom, what happens to the wave form?

wavelength decreases and height increases