Download Effects of Constructive and Destructive Forces on the Earth`s Surface

Constructive/Destructive Forces Study Guide
Definitions:
Constructive Force Processes that create landforms
Destructive Forces Processes that destroy landforms
Weathering Weathering is a general term used to describe processes that break down rocks
at or near the surface of the earth. Weathering can be either physical or chemical (caused by
oxidation(rust) or acid rain). These processes cause the surface of the earth to dissolve,
decompose, and break into smaller pieces. Water is an important cause of weathering. Plants
cause weathering when roots break apart rock. Changes in temperature can break rock, as
well as ice forming inside cracks in the rock causing it to break even more. Anything that
causes rocks to wear down or break apart is a cause of weathering.
Erosion
Erosion is the movement of sediments and soil by wind, water, and gravity.
Fault A deep crack in the Earth’s surface where plates slide against each other. The San
Andreas Fault is an example of a strike slip fault
Or Reverse
Deposition Deposition is the dropping, or depositing, of sediments by water, wind, or ice.
Deposition builds up new land on Earth’s surface, like a delta at the end of a river or the pile
up of a sand dune in the desert. Shells on the beach are deposition by ocean waves.
Delta
A triangle shaped landform created at the mouth of a river by deposition.
Organisms Some can be destructive forces. Ex. Lichen, trees - roots, burrowing animals.
They break down other things into smaller pieces.
Landslides Landslides are mass movements of land due to gravity. Landslides can cause
buildings to fall, or power and gas lines to break. Landslides even occur on the continental
slope in the ocean.
Volcanic eruptions Volcanoes are mountains with openings in Earth’s crust through which
magma, gases, and ash reach Earth’s surface. Volcanoes can change Earth’s surface. When
the magma erupts from the volcano the top of the mountain can be changed. The lava and
ash can destroy forests and bury fields. Volcanic eruptions can even change Earth’s weather
patterns. Volcanic eruptions also occur under the oceans; these volcanoes that are built up
are called seamounts.
Earthquakes
Earthquakes are vibrations on Earth’s surface caused by sudden
movement in Earth, often along a fault, a break in Earth’s surface. Some earthquakes cause
little damage and some cause a lot of damage. Large earthquakes can cause landslides.
Earthquakes under the ocean can cause huge waves, called tsunamis that destroy land and
cause great damage if they come ashore.
Floods
Floods occur when a large amount of water covers land that is usually dry.
When the flood occurs, rapid erosion can take place and move soil and sediments away.
When the flood recedes, new sediment is left behind and can build up rich soil deposits.
Surface features Any feature of Earth's surface having a distinct shape and origin.
Landforms Include continents, ocean basins, plains, plateaus, and mountain ranges as well
as hills, valleys, slopes, and dunes.
Technology
Technology and human intervention can control constructive and destructive processes.
Examples include, but are not limited to:
 seismological studies: used to measure earthquakes
 flood control, (dams, levees, storm drain management, etc.)
 beach reclamation (Georgia coastal islands)
Dam A structure that goes ACROSS a body of water
Levees Structures that are found on the SIDES of water
Beach Reclamation Dredging, jetties, plants, adding sand
Types of Volcanoes
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Cinder: usually steep and erupts
Shield: is broad with gently sloping sides. It usually does not erupt; lava continuously
flows from it.
Composite: usually erupts and has lava continually flowing from it.
Mountain Formation
 Fault Block Mountains: form when masses of rock move up or down along a fault.
 Folded Mountains: form when two tectonic plates collide. The Appalachian Mountains
are an example of these.
Mercalli Intensity Scale Measures effects (damage) of earthquakes on people, buildings,
bridges, and community.
Richter Magnitude Scale
Measures the magnitude of earthquakes. Scientists use the
RMS scale to gain important information about what is going on in the Earth’s interior
Some Review Questions
1. Which natural processes can cause new land to form (are constructive forces)?
Deposition, earthquakes, volcanoes, and faults
2. Which natural processes can tear down the land and cause landforms to be destroyed
(are destructive forces)?
Weathering, erosion, impact of organisms, earthquakes, and volcanoes
3. Which natural processes can both build up and tear down the land (both constructive
and destructive forces)?
Landslides, volcanoes and floods
4. Explain how these processes can do both.
They cause BOTH weathering and deposition, therefore they break down the earth
and build it up somewhere else!
5. List six causes of weathering.
Water, change in temperature, plant roots, ice (glaciers), wind and gravity
6. List four agents of erosion. Circle the strongest agent of erosion.
Water (strongest), wind, ice and gravity
7. List three agents of deposition.
Water, wind and ice
8. Deposition can create what two types of landforms?
Delta and dunes (The 3 Ds are Deposition = deltas and dunes)
9. What is the difference between the Mercalli Intensity Scale and the Richter Magnitude
Scale? Which one would scientists use most often?
MIS- measures effects (damage) of earthquakes on people, buildings, bridges, and
community. RMS – measures the magnitude of earthquakes. Scientists use the RMS
scale to gain important information about what is going on in the Earth’s interior.