Landforms and Oceans Support Document
Natural Processes 5-3.1
p. 1 of 2
I. Natural Processes
 Events of nature that happen causing changes to Earth’s land and oceans are called
Natural Processes.
 These changes can result in either creating landforms or destroying landforms.
 Processes that create landforms are called constructive.
 Processes that destroy landforms are called destructive.
 Examples of destructive processes are: weathering, erosion, landslides, earthquakes,
volcanic eruptions, and floods. These are discussed below.
 Examples of constructive processes are: deposition, volcanic eruptions, landslides, and
floods. These are discussed below.
II. Weathering; Destructive
 Weathering is anything that causes rocks to wear down or break apart into smaller pieces
at or near the Earth’s surface. (Weathering = Break)
 There are two categories of weathering: physical weathering and chemical weathering.
 These processes cause the surface of the Earth to dissolve, decompose and break into
smaller pieces.
 Causes of weathering:
- Water; important cause of weathering.
- Plants ; when roots break apart rock
- Temperature changes; causes rock to break
- Ice; forms inside of cracks in rocks causing it to break even more.
- Anything else that causes rock to wear down or break.
III. Erosion; Destructive
 Erosion is the movement of sediments (pieces of earth) and soil. (Erosion = Movement)
 Effect of deposition
- Movement of sediments and soil
 Causes of erosion:
- wind
- water
- gravity
- ice
IV. Landslides; Destructive/Constructive
 Landslides are mass movements of land due to gravity. (Landslide = mass movement)
 Effect of landslides
- buildings fall
- power lines break
- gas lines break
 Cause of landslides
- Gravity
- Even occur on the continental slope in the ocean.
p. 2 of 2
V. Earthquakes; Destructive
 Earthquakes are vibrations on Earth’s surface caused by sudden movement in Earth.
 Effects of earthquakes
- Sometimes little damage is done/sometimes a lot of damage.
- landslides (if a large earthquake)
- Tsunamis or HUGE waves (if earthquake is under the ocean) that destroy land and
cause great damage if they come ashore.
 Causes of earthquakes
- sudden movement in earth
- faults ( a break in Earth’s surface) – these often cause the sudden movement
VI. Floods; Constructive and Destructive
 Floods occur when a large amount of water covers land that is usually dry.
 Effect of floods
- rapid erosion, moving soil and sediments away (destructive)
- rich soil deposits left behind when flood recedes (constructive)
 Cause of flooding
VII. Deposition; Constructive
 Deposition is the dropping, or depositing of sediments. (Deposition = Dropping / Building
up)
 Effect of deposition
- New land building up on Earth’s surface
 Causes of deposition
- Water; ex: shells on the beach are deposition by ocean waves or delta at the end
of a river.
- Wind ; ex: sand dunes on the desert & beach are deposition by wind
- Ice : ex: glaciers push debris as they slide, causing it to build up
VIII. Volcanic Eruptions; Constructive/Destructive
 Volcanoes are mountains with openings in Earth’s crust
 Seamounts are volcanoes that are built up under the ocean- if it rises above ocean
surface it causes seamounts ex: Japan, Hawaii
 Volcanic Eruptions occur when magma, gases, and ash reach Earth’s surface.
 Effect of volcanic eruptions
- Changes in Earth’s surface
- changes in top of the mountain (volcano)Constructive- top built up
Destructive- exploded off
- lava and ash can destroy forests and bury fields
- can cause changes in weather patterns
 Under the ocean