Earthquake and Volcano Notes

• Earthquake- the shaking and trembling that results from the crust moving. • Deformation- any change in the

shape or volume of the crust.

Stress- a force that acts on rock and changes earth’s shape or volume.

There are three types of stress- Shearing, Tension and Compression

shearing

compression

Parts of a fault• Hanging wall- the half of the fault

that lies above the fault. • Footwall- the half of the fault that

lies below the fault.

Types of faults

There are three types of faults:Strike Slip fault, Normal fault and Reverse fault

Parts of an Earthquake• Focus- exact point where the

fault moves underground.• Epicenter- the point on the

surface directly above the focus. • Seismic waves- earthquake waves

that travel outward like ripples in a pond.

Types of Seismic Waves

Primary Waves- (P-waves)–Strongest waves–1st waves –Compressions

Secondary Waves- (S Waves)- up and down movement- can’t go through liquids

Surface Waves- P & S waves that reach the surface. These are the most destructive

• Seismic waves transfer mechanical energy

• The Wasatch Fault is a normal fault

Volcano Notes• Parts of a Volcano–Magma chamber- large underground

pocket of magma

–Vent or pipe- tubes leading to the surface

–Crater- bowl shaped area at the top

Magma• Magma is below the surface• It rises because it is less dense• Contains gases• Sometimes thick and sometimes

thin• Different amounts of silica• Flowing magma transfers heat and

mechanical energy.

Types of Eruptions

• Quiet Eruption–Low silica–Fast moving lava•Hawaii

–Pahoehoe and Aa

• Explosive Eruption–High silica–Pipes get clogged–Pressure and gas build up until

it explodes–Ash and pyroclastic flow–Example: Mt. St. Helens

Types of Lava

• Pahoehoe- hot, fast moving lava–Like a river

• Aa- slower, chunkier lava• Pyroclastic Flow- large cloud of

debris and ash flowing very fast down the volcano

Types of Volcanoes• Active- An erupting volcano.–About 600–Ring of fire- ring of volcanoes

around the pacific ocean• Dormant- A sleeping volcano.• Extinct- A dead volcano.

Not every volcano is the same.