what is the crack in the ocean floor through which magma rises?
according to Wegener, what happened about 250 million years ago?
the supercontinent began breaking into smaller continents
tectonic plates are blocks
at the center of a mid-ocean ridge is a(n)
the composition of Earths interior affects
the speed and direction of seismic waves
Which scale more accurately measures the magnitude of large earthquakes?
If you are tn a" aar during an earthquake, youshould
stop the car in a safe place
what happens to tsunamis as they move toward shore?
They increse in height.
If you are in indoors during an earthquake, you should
stay away from windows.
Which of the following is NOT a cause of tsunamis?
If you are indoors during an eathquake, you should
crouch under a desk.
How does the structure of Earth' s interior affect seismic waves?
It can affect the speed and direction of seismic waves.
Which of the following are studied to forecast earthquakes?
seismic gaps, foreshocks, rock changes
Why do earthquakes usually occur at plate boundaries?
Rock in environments near tectonic plate boundaries experience great stress.
S waves are also known as
Fault zones form a tplate boundaries because
intense stress occurs therc when the platesseparate, collide, subdufrt, or slide past eachother.
What forms on the oceanl floor in a subduction zone?
Volcanic eruptions may be signaled by
A large depression formed by the collapse of a volcanic cone is called a
Volcanic ash, dust, blocks, bombs, and lapilli ara all
The eruption of Mount St. Helens was
en explosive eruption.
Three events that might signal a volcanic eruption aro changes in earthquake activity, volcano surface bulges, and
a sulfuric odor
Modsrn oceanography began with
the HMS challenger
most mid-ocean ridges form
in areas of increased volcanic activity
a piece of sediment collected by drilling a
the most common compounds im organic sediments are
silica and calcium carbonate
to calculate the depth of the ocean floor with sonar, scientists measure
the time it takes sound waves to travel
the source of most calcium carbonate in biogenic sediments is
most oxygen enters the ocean form
what is called the foundation of life in the ocean
the ocean is the main source of the trace minerals
chloride and sodium
most offshore oil and peroleum deposits are found
on the continental shelf
in addition to increase usr of toxic chemicals, what has reduced the ocean's abilitly to renew itself
increase world population
in addition to limiting the use of leaded gasoline, what has the united stares done to reduce ocean pollution
bannes the toxic chemical DDT
trace elements in the ocean are those minerals that are
smalest in amount
volcnaic eruptions chemical weathering rock on land and chemical reaction between sea water and nexly formed sea-floor rocks provide most of the raw elements that form this dissolved solid in the oceam
where would a tidal bore occur?
where a river enters the ocean
the curving of the path of ocean currents and wind belts is called?
the Coriolis effect
the force that causes tides is
very large waves are usually the result of
a long fetch
in the tropical latitudes, trade-wind belts push currents
sandbars are formed by
as lower layers of air are warmed
the air rises
what air masses generally moce eatward, toward Europe
maritime poplar Atlantic
a large body of air throughout which temperature and moisture content are similar is an
continental polar, maritime polar, continental tropical, and maritime tropical are types of
Doppler radar and satellite images provide information to create
a pattern of meteorological symmbols that represent the weather at a particular abserving station is a
when air moves slowly, it takes on the temperature and hummidity of its region, becoming an