Homework #4 questions Flashcards
Comparing waves to ocean currents, waves are the agents of ___ and ocean currents are the agents of ____ and ____
waves are agents of erosion
ocean currents are agents of transportation and deposition
Land features created by wave erosion include what two things?
Rocky Cliffs and Headlands
Depositional features include what (2) things?
Beaches and Sandbars
How are waves and ocean currents generated?
There is global patterns of pressure and wind caused by Earth’s unequal warming by the sun. Wind blowing over water’s surface initiates waves and ocean currents. Tidal fluctuations and tectonic events also contribute to movement of large bodies of water.
Do waves actually shift of move the water horizontally? explain
no the energy of the wave moves through the water
Most waves are ______ generated, set in motion by what?
wind generated set in motion by the friction of air blowing across the water
A small number of waves are generated by something other than wind. List those (3) factors
Tidal surge
Volcanic activity
Undersea tectonic movement
The horizontal distance from crest to crest or from trough to trough is called what?
wavelength
What is the most notable erosion on coastlines accomplished by?
wave action
Spray from breaking waves commonly moves as fast as __ mph
70
What type of rock classification is sandstone?
sedimentary
Most tsunami are consequence of what?
sudden disruption of ocean floor fault
Tsunami may also result from what?
underwater volcanic eruptions and major underwater and coastal landslides
Out in the open ocean, tsunami are usually quite ___.
inconspicuous
Why is it hard to notice a tsunami in open ocean?
bc they are low and have very long wavelength
Tsunami can travel at speeds exceeding_____ mph
435
When a tsunami reaches shallow water, how does it change?
as a tsunami approaches a coast, it slows, causing the wavelength to decrease and the wave height to increase.
How high can wave height become?
130 ft
What caused the Sumatra-Andaman Earthquake and Tsunami of 2004?
750 mile long section fo the Indo-Austrailian plate subducted beneath the Burma Plate. the ocean floor lifted 16 ft, causing a tsunami to spread in all directions
What are the (2) different circumstances that cause sea level to change?
Tectonic cause: landmass uplifting or sinking
Eustatic Sea level change: Amt of water in oceans increasing or decreasing
Sea level changes of greatest magnitude are associated w/ ______ before, during , and after ?what event? where sea levels dropped 430 ft worldwide
seawater volume
the pleistocene glaciations
A relative rise in sea level results in a shoreline of ______
submergence
in the recent geological past, sea level ___ sharply
fluctuated
about 125,000 years ago sea level was about ____ higher that it is today.
20
During the last glacial peak sea level is est. to have been around ____ ft lower than it is today.
400
Why do almost all the world’s oceanic coastlines show evidence of submergence during the last 15,000 years?
bc as a result of the melting of the pleistocene ice sheets. As water from melting glaciers went into the ocean, rising sea levels caused widespread submergence of coastal zones.
