Leading edge shorelines
tectonically active, irregular shorelines, rugged topography, restricted beaches, numerous mass-wasting hazards
Trailing edge shorelines
tectonically inactive, relatively straight shorelines, low-lying topography, broad, extensive beaches, few mass-wasting hazards
Most ocean waves result from the transfer of ___ energy to a body of water.
wind
Wave energy travels ___ through water, whereas water molecules move ___.
horizontally; in circular paths
The movement of water molecules gets progressively ___ with depth, eventually reaching what is referred to as wave base.
smaller
As wave energy increases, wavelength ___ and wave base becomes ___.
increases; deeper
Near shore waves
lower velocity, shorter wavelength, taller wave height, non-symmetrical wave shape
Off shore waves
higher velocity, longer wavelength, lower wave height, symmetrical wave shape
As a wave approaches land, the end ___ to shore encounters the seafloor first, forcing the wave to slow down while the other end travels at its original speed.
closest
This causes a difference in ___, which in turn causes the wave to bend or refract toward shore.
velocity
___ push water up the beach, creating a zigzagging path as the water flows back into the surf zone. This is important as it causes sediment to drift parallel to shore in a process known as ___.
Breaking waves; beach drift
Wave refraction also forces water to flow ___ to shore in what is known as a longshore current.
parallel
On irregular shorelines, waves first begin to break on the ___, which results in ___ that transport eroded material into ___.
headlands; longshore currents; coves
As this process continues, the beaches eventually merge and form relatively straight shoreline segments where sediment is transported ___ to shore.
parallel
Storm surge not only inundates areas normally above high tide, but also brings ashore ___ that easily demolish most structures.
breaking waves
Storm surge forms in part due to the ___ in air pressure toward the eye of a hurricane, which allows the sea surface to rise, creating a dome of water that follows the storm inland.
decrease
Even higher storm surge is generated on the northeastern side of the eye due to the combined effects of the storm's counterclockwise ___ and intense ___.
rotation; winds
Rip currents form when ___ funnels through a break in underwater sand bars.
backwash from the surf zone
If caught in a rip current while swimming, the best approach is to stay calm and swim ___ to shore. After you get beyond the narrow zone where the current is operating, it then becomes quite easy to swim back to shore.
parallel
Rip currents can be recognized by how they ___ within the surf zone.
disrupt breaking waves
In areas of chronic erosion, beach nourishment is often the only solution for bringing back a ___.
recreational beach
However, adding sand does not address the underlying reason the ___ in the first place.
beach is being starved
The new sand will ___, which makes beach nourishment an ___ option.
eventually be lost; on-going and expensive
There are two basic types of shorelines in terms of plate tectonics: leading edge (active) and trailing edge (passive). Which of the following best describes leading edge shorelines?
steep slopes, irregular coastline, restricted beaches
Which of the following best describes the cause of ocean tides?
Earth's spinning motion and gravitational effect of the Moon and Sun.
Currents out in the open ocean are primarily driven by which of the following?
prevailing winds and density differences of the water
Which of the following are key characteristics of ocean waves?
energy travels horizontally and water molecules move in a circular manner
What best explains how surf forms along a shoreline?
waves beginning to drag on the seafloor and slowing down
Which of the following explains why longshore currents develop along shorelines?
wave refraction
Why are longshore currents important in environmental geology?
cause the beach itself to migrate over time
What best describes why irregular shorelines evolve and become straighter over time?
waves erode headlands and deposit sediment in coves and bays
Which of the following is the primary mechanism that causes barrier islands to retreat (migrate) toward the shoreline?
storm overwash
Hurricanes cause a regional rise in sea level (dome of water) that can result in a very dangerous phenomenon known as storm surge. What best explains the cause for this rise in sea level?
high winds and lower air pressure within the storm
Which of the following is the energy source that provides power for tropical storms and hurricanes?
warm seawater
What is the most effective means of minimizing the structural damage that results from the high winds of a hurricane?
strap the roof to the frame and board the windows
Tsunamis can form in a variety of ways. Which of the following will NOT cause a tsunami?
strong winds
Shoreline retreat is a natural process that humans have made worse in recent years. Which of the following is NOT a major factor in the rate at which shorelines move inland?
coastal development
Seawalls are commonly used to stop shoreline retreat. Which of the following is a negative consequence of building a seawall?
loss of the beach at high tide
Beach nourishment is a common technique for minimizing shoreline retreat. Which of the following is a negative consequence of beach nourishment?
is costly and must be done periodically
Breakwaters are commonly used in coastal engineering. What is the basic purpose of installing a breakwater?
create a quiet area to moor boats and reduce erosion
Over the past 3 million years, sea level has been as much as 400 feet lower and 100 feet higher compared to today.
True
Mass wasting hazards are less likely to occur along trailing edge (passive) shoreline than along leading edge (tectonically active) since the slopes are typically much more gentle.
False
Should you ever find yourself being swept out to sea in a rip current, it is important to immediately try to swim directly back to shore.
False