The Geosphere 3.1 p.58-66

Our Dynamic Earth!

The Earth as a System The Earth is a system 4 parts: rock, air, water, and living things that interact with each other. 4 parts: Geosphere (rock) Atmosphere (air) Hydrosphere (water) Biosphere (living things)

Geosphere Geosphere- the solid part of Earth. all rock, soils, and sediments Scientists have only drilled 12km deep.

How do we learn about inside of the Earth? They study the Earth’s interior by seismic waves. Same waves that are caused by earthquakes. Measure changes in speed/direction of seismic waves. From this, they found that Earth is layered, and have hypothesized about what those layers consist of.

Composition of Earth 3 Layers: 1. The crust- thin outer layer. (light elements). 1% of Earth’s mass 2. The mantle- the layer beneath the crust. (elements have medium density) 64% of Earth’s mass 3. The core- innermost layer (dense elements) Radius is 3,400 km

Layers of the Earth:

Plate Tectonics Tectonic Plates- pieces of the lithosphere that move back and forth. Plate Boundaries- boundaries between tectonic plates. This is where plates separate, collide with one another, or slip past one another. These forces cause earthquakes and volcanoes.

Plates Moving

Plate Tectonics and Mountain Building When tectonic plates constantly move, rock breaks/buckles. Plates collide, crust becomes thicker, and mountain ranges form. Himalaya Mountains: tectonic plates of India and Asia collided 50 million years ago.

Northern India’s Himalayan Mountains

Earthquakes Fault- break in the Earth’s crust where blocks of Earth slide by each other. Earthquakes- vibrations of the Earth’s crust that are caused by slippage along a fault. Earthquakes happen all the time—we don’t feel all of them. The majority of earthquakes happen at or near tectonic plate boundaries.

Richter Scale Used by scientists to measure amt. of energy released by earthquakes. magnitude- the measured amount of energy coming from a quake. Smallest 2.0 and largest ever recorded is 9.5 Each whole number is 31.7 times more magnitude

Volcanoes Volcano- mountain built from magma (melted rock) that rises from the Earth’s interior to the surface. Located near tectonic plate boundaries where plates are colliding/separating

Earthquake Hazard Areas Scientists can’t predict when earthquakes will occur. Earthquake-hazard level is determined by its past and present seismic activity. Earthquakes can occur in areas that are not labeled as high-risk. High risk areas have started to build earthquake-resistant structures. Flexible so they will sway with ground motion.

Local Volcanic Effects Clouds of hot ash, dust, and gases flow up to 200 km/hr. Can mix with water and produce a mudflow. Causes building collapse. Buries crops and vehicles. Causes breathing problems

Global Volcanic Effects Can change Earth’s climate for several years. Sulfur-gas goes into the atmosphere. 1991: Mount Pinatubo in the Philippines Ash/gas entered atmosphere Sunlight decreased by 2-4% Avg. global temp. dropped by 10ths of degrees Celsius over several years

Erosion Erosion- removal and transport of surface material Wears down rocks Makes them smoother

Water Erosion Water Erosion- erosion by rivers and oceans. Waves erode coastlines Rivers create gorges Wind Erosion- erosion by wind Places where there are little/no plants to block winds Beaches, deserts (loose sandy soil)

The End