2.2b earthquakes and volcanoes

18
Earthquake s Vocabulary Focus – the area along a fault at which slippage first occurs, initiating an earthquake. Epicenter – the point on Earth’s surface directly above the focus.

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Page 1: 2.2b  earthquakes and volcanoes

Earthquakes Vocabulary• Focus – the area

along a fault at which slippage first occurs, initiating an earthquake.

• Epicenter – the point on Earth’s surface directly above the focus.

Page 2: 2.2b  earthquakes and volcanoes

EarthquakesVocabulary• Seismic waves –

waves of energy that travels through the earth as a result of earthquakes, explosion or heavy impact on Earth.

• Kinds of Seismic Waves:• P waves• S waves• Surface waves

Page 3: 2.2b  earthquakes and volcanoes

Earthquakes Vocabulary• P waves – Primary

Waves; the longitudinal waves generated by an earthquake.

• S waves – secondary waves; the transverse waves generated by an earthquake.

Page 4: 2.2b  earthquakes and volcanoes

Earthquakes Vocabulary• Surface waves –

Surface waves are analogous to water waves and travel along the Earth's surface.

Page 5: 2.2b  earthquakes and volcanoes

What Are Earthquakes

• Earthquake - A sudden and violent shaking of the ground, sometimes causing great destruction, as a result of movements within the earth's crust or volcanic action.

Page 6: 2.2b  earthquakes and volcanoes

What Are Earthquakes

• Occur mostly at the boundaries of tectonic plates when plates shift.

• Rocks along edges of tectonic plates experience immense pressure.

Page 7: 2.2b  earthquakes and volcanoes

What Are Earthquakes

• Rocks break as stress becomes so great.• Energy is released as seismic waves when

rocks break along fault line.

Page 8: 2.2b  earthquakes and volcanoes

What Are Earthquakes• The exact place

where the rocks first break where the earthquake originates is called the focus.

• The Point on the surface directly above the surface is called the epicenter.

Page 9: 2.2b  earthquakes and volcanoes

Energy is transferred by waves• P waves also

known as longitudinal waves, move faster through rocks than other seismic waves.

• So they are the first waves experienced

Page 10: 2.2b  earthquakes and volcanoes

Energy is transferred by waves• P waves travel

by compressing Earth’s crust in front of it and stretching the crust behind it.

Page 11: 2.2b  earthquakes and volcanoes

Energy is transferred by waves• S waves are also

known as transverse waves.

• They move more slowly through Earth.

• Thus called secondary waves (S waves)

Page 12: 2.2b  earthquakes and volcanoes

Energy is transferred by waves• S waves motion

is like that of a rope shaken up and down and/or side to side.

Page 13: 2.2b  earthquakes and volcanoes

Earthquakes Vocabulary• Seismology – the

study of earthquakes and related phenomena.

• Seismologist – a person studying seismology

Page 14: 2.2b  earthquakes and volcanoes

Earthquakes Vocabulary• Richter scale – a

scale that express the relative magnitude of earthquakes.

• Seismograph – a machine that records earthquake data.

Page 15: 2.2b  earthquakes and volcanoes

17.2 Kind of Volcanoes• Shield Volcano Magma rich in iron and

magnesiumVery fluidLava flows great distances

Eruption mildEruption occur several timesLava produces gently sloping

mountain

Page 16: 2.2b  earthquakes and volcanoes

17.2 Kinds of Volcanoes• Composite Volcano

Made up of alternating layers of ash, cinders and lava

Magma is thicker Gases are trapped in the

magma making explosive eruptions

Typically thousand meters high

Steeper cones than shield volcanoes

Page 17: 2.2b  earthquakes and volcanoes

17.2 Kinds of Volcanoes• Cinder Cone

Smallest and most abundant volcanoes

Tend to be active for a short time then become dormant

Vast quantities of ash and lava fall around vent that form the cone

Gas-trapped magma – explosive eruption

Page 18: 2.2b  earthquakes and volcanoes

17.2 Earthquakes and Volcanoes• Kinds of Volcanoes