1. Environmental Science
Chapter 3 Section 1

2. Earth
Earth is an integrated system that consists of rock, air, water, living things all interacting together
Geosphere- rock
Atmosphere- mixture of the gases we breathe
Hydrosphere- all the water
Biosphere- part of E where life exists

3. Geosphere
The geosphere is the part of E consisting of all rock, solids, and sediments on E’s surface.
Geologists study E’s interior by using seismic waves
Same wave that travel through E during earthquake
Seismic waves work in the same way tapping a melon to test for ripeness tells us about the contents of the inside based on the type of sound that we hear

4. Geosphere
Seismic waves are altered by the nature of materials it travels through
Seismologists measure changes in speed and direction of seismic waves
Seismologists have learned that E is composed of different layers and have inferred what substances make up those layers
The 3 layers of the E are: crust, mantle, core

5. Crust
The crust is the thin outer layer made almost entirely of “light” elements
Responsible for less than 1% of planet’s mass
5-8 km thick beneath the ocean
20-70 km thick beneath the continents

6. Mantle The mantle lies beneath the crust
Responsible for 64% of the planets mass
2900 km thick
Made of rocks of medium density

7. Core The core is the innermost layer of the E.
Composed of the densest elements
Radius of 3400 km

8. Lithosphere
The E can be divided into 5 layers based on physical properties
Lithosphere
Outermost layer
Cool, Rigid
km thick
Includes crust and upper mantle
Divided into tectonic plates

9. Tectonic Plates
Tectonic plates glide across underlying layer as ice drifts over a pond
Continents are on tectonic plates and move along with them
The major plates are:
Pacific
No. American
So. American
African
Eurasian
Antarctic

11. Tectonic Plates
Much of the geologic activity at the surface of E takes place at boundaries between plates
Forces produced at boundaries can form mountains, cause earthquakes, and erupt volcanoes
Mountain formation is caused by crust collisions and increase thickness giving mtn. ranges

12. Asthenosphere The asthenosphere is the layer beneath the lithosphere
It is a plastic, solid layer of the mantle
Made of rock that flows very slowly and allows tectonic plates to move on top

13. Inner Layers Mesosphere Outer core Inner core Lower part of mantle
Dense liquid layer
Inner core
More dense solid layer
Mostly iron and nickel
degrees Centigrade
Despite heat, core is solid due to intense pressure

14. Earthquakes
A fault is a break in the Earth’s crust along which blocks of the crust slide relative to one another
When rocks under stress break along a fault, vibrations are set off
These vibrations of the E’s crust are earthquakes

15. Earthquakes
The Richter scale is used by scientists to quantify the amount of energy released by an earthquake
The measure of the energy released is called magnitude
Smallest magnitude measured is 2.0
Magnitude of 7.0+ cause widespread damage
Largest magnitude ever recorded is 9.5
Each increase of magnitude by one whole number indicates the release of 31.7 X more energy than the whole number before it.

16. Earthquakes
Earthquakes take place at or near tectonic plate boundaries due to large stresses generated when plates separate, collide, or slip past each other
Earthquakes are not limited to these boundaries
Scientists can not predict when or where earthquakes occur

17. Volcanoes
A volcano is a mountain built from magma (melted rock) which rises from E’s interior to the surface.
Often located near plate boundaries where plates are either colliding or separating from one another
Occur on land or in sea
Under the sea volcanoes may eventually break the surface as islands

18. Volcanoes Local effects of volcanic eruptions can be Ash Dust Gases
Bury crops
Collapse buildings
Damage car engines
Cause breathing difficulties
Dust
Gases
Mudflow from ash mixing with water

19. Volcanoes Global effects of large volcanic eruptions can be
Clouds of ash and gases reaching the upper atmosphere
Ash can reduce the sunlight reaching E’s surface

20. Volcanoes
The largest observed volcanic eruption in the last couple centuries occurred in 1815 in Indonesia. The island was once 4000m tall but the volcano, Tambora, blew off a quarter of its height in it’s eruption. At the end of the 5-day eruption, he mountain had diminished to 2850m. The eruption killed people, ruined ag land, destroyed settlements. Explosion was so violent that debris shot 48km into the stratosphere and blocked 1/5 of solar energy that reached the E. The light and heat reduction was felt globally. It caused unusual weather patterns around the world and widespread crop failure. In some places, snow and frost occurred as late as June. This gave the year 1815 the name “the year without a summer”.

21. Erosion
Forces at the boundaries of plates bring rocks to the surface of the E
At the surface, rocks are altered by other forces
The removal and transport of surface material is called erosion
Erosion wears down rocks and makes them smoother
The older a mtn. range, the longer erosion has acted upon it.
Knowing this helps scientists gauge age of a mtn range.
The Appalachian Mtns. Are round-topped and deemed older than the jagged-topped Rocky Mtns.

22. Erosion Water erosion Wind erosion Erosion by rivers and oceans
Places with few plants erode more quickly due to wind