EARTH & SCIENCE

Earth is a dynamic planet due to?

both internal and external forces

Compositional

What it is made of

Mechanical

How it behaves

Crust

Outermost thinnest layer (5-70km thick)

Continental crust

Thick, less dense, made of granite

Oceanic crust

Thin, dense, made of basalt

Crust is mostly composed of

silicon (Si), oxygen (O), aluminum (Al)

How much mass does the crust make up for?

Makes up less than 1% of

Earth’s mass

Mantle

Extends from the base of the

crust to 2,900 km deep

How much volume does the mantle cover?

Largest layer by volume (84%)

Mantle is composed of

Composed of silicate rocks

rich in magnesium (Mg) and

iron (Fe)

Matter and motion of mantle

Solid, but flows slowly

Outer core

Liquid, and its motion creates Earth's magnetic field

Outer core is composed of

Composed mainly of liquid iron and nickel

Inner core

Solid, due to the immense pressure

despite extreme heat

Inner core is mostly composed of

Made mostly of solid iron

and nickel

Lithosphere

The outermost mechanical layer, consisting of the crust and the uppermost part of the mantle

Lithosphere

It behaves like solid, brittle rock and is

divided into tectonic plates that float on

the underlying layers

Lithosphere

The average thickness of the lithosphere is about 80 km, but it varies depending on whether it is under oceans or continents.

Asthenosphere

located beneath the lithosphere

Asthenosphere

Is a soft, ductile layer of the upper mantle

Asthenosphere

although it is solid, the high temperatures allow it to flow slowly over geological timescales. This layer is crucial for the movement of tectonic plates above it.

Mesosphere

Lower mantle, lies beneath the asthenosphere

Mesosphere

Characterized by high pressure and temperature, which makes it rigid despite being composed of solid silicate materials.

Parts of the compositional layer

Crust, mantle, core

Parts of the mechanical layer

Lithosphere, Asthenosphere, mesosphere, inner core, outer core

Major ocean surrounded by the ring of fire

Pacific ocean

7 major tectonic plates

North American plate, South American plate, Eurasian plate, African plate, Arabian Plate, Indo-Australian plate, Antarctic plate

Ring of fire

A vast horseshoe-shaped zone around the Pacific Ocean, approximately 25,000 miles (40,000 km) long and up to 500 km wide

Ring of fire

Responsible for 75% of Earth's active volcanoes and 90% of the world's earthquakes

Ring of fire

The result of tectonic plates, huge slabs of Earth's crust that fit together like pieces of a puzzle.

Ring of fire

Also home to hot spots, areas deep inside Earth's mantle from which heat rises.

Plate boundaries

The edges where two or more

tectonic plates meet.

Major mountain belts

are long, continuous chains of mountains that stretch across large regions of the Earth, often thousands of kilometers.

Earthquake

Sudden shaking in Earth’s surface

Earthquake

Energy release in rocks

Earthquake

Seismic waves

1st reason for an Earthquake

Tectonic plate movement

2nd reason for an earthquake

Fault stress

3rd reason for an earthquake

Volcanic activity

4th reason for an earthquake

Human activity

Focus/hypocenter

Point of origin

Epicenter

Surface point above focus

Fault

Fracture line

Body waves

These waves travel through the Earth's

interior

P-waves (Primary wave)

fastest seismic waves and can travel through solids, liquids, and gases.

S-waves (secondary waves)

slower than P-waves and can only travel through solids. Can cause particles to move perpendicular to the direction of wave propagation.

Surface waves

These waves travel along the Earth's surface and are typically more destructive during earthquakes.

Love waves

cause horizontal motion and are faster than Rayleigh waves.

Rayleigh waves

Creates an elliptical motion, similar to Ocean waves, and are usually the most damaging type of seismic wave.

Seismograph

Instruments used to measure earthquakes

Seismogram

traces of amplified, electronically recorded ground motion made by seismographs

Magnitude 1 (micro)

So small that people cannot feel them, only sensitive instruments like seismographs can detect them.

Magnitude 2-3 (minor)

Very small earthquakes. People may not feel them, but they are recorded by instruments.

Magnitude 4 (light)

Now the shaking can be felt indoors, like a heavy truck passing by. Usually causes no damage.

Magnitude 5 (moderate)

Shaking is stronger. Some objects may fall, windows may rattle, and weak structures can be damaged

Magnitude 6 (strong)

Buildings and houses can be damaged. It is strong enough to be dangerous, especially near the epicenter.

Magnitude 7 (major)

This is a major earthquake. Severe damage occurs to poorly built buildings. It can be destructive across a wide area.

Magnitude 8 (great)

A truly great earthquake. Many buildings collapse, roads and bridges are destroyed. Tsunamis may be generated. Affects hundreds of kilometers.

Magnitude 9 (rare, catastrophic)

Extremely rare, causes massive destruction over very large areas.

Magnitude 10 (Theoretical maximum)

This is the strongest possible earthquake, but none has ever been recorded in history. It would cause unimaginable global damage.