PART 7: “VOLCANO EXPLORER” ACTIVITY

GLOBAL PERSPECTIVETECTONIC PLATES:

The Earth's crust is broken into tectonic plates that fit together like a puzzle.

Most of the Earth's active volcanoes can be found along these plate boundaries.

RING OF FIRE: The Ring of Fire is one of the Earth's most

active volcanic zones. It runs around the Pacific Ocean. On

the map below, show the area of the Ring of Fire.

LAYERS WITHIN The plates, which make up Earth's

lithosphere, float on a semi-solid layer of molten rockcalled the mantle or the asthenosphere.

The mantle has two layers: (1) the upper mantle which is more solid and (2) the lower mantle which is more liquid.

The lithospheric plates are constantly moving slowly, colliding with or drifting away from each other.

Volcanoes form when this magma forces its way through weak spots in the lithospheric plates.

This is most often at a plate boundary (where two plates meet).

Volcano typesVolcano types

Inside a Volcano

The magma is relatively buoyant compared to the surrounding rock because it is hotter, and hotter

things become less dense, causing them to rise above the rest. This increased buoyancy causes it to rise

upward.

When pressures are great enough, the magma ejects through the central vent and exits the volcano.

A dike is a region of magma that pushed out of the magma chamber and solidified, but never

reached the surface.

Build your own volcano

Three factors affect the size of the volcano and strength

of the eruption:

(1)Viscosity = resistance to flow, or

“thickness” of the magma.

(2) Amount of Gas

(3) Amount of Silica (the more silica,

the higher the viscosity!!)

Generally, stronger eruptions are caused by __higher___ viscosity, __higher___ gas, & _higher_ silica.

CLICK THE VOLCANO For CLICK THE VOLCANO For

Volcano Explorer!!Volcano Explorer!!

PART 8: LITHOSPHERIC PLATE PUZZLE LAB

PART 9: VOLCANO & POMPEI VIDEOS

VOLCANO SITES

Virtual Volcano: http://dsc.discovery.com/convergence/pompeii/interactive/interactive.html

Crater Lake: http://planetoddity.com/wp-content/uploads/2010/03/crater-lake-1.jpg

Birth of an Island: http://www.snopes.com/photos/natural/maiken.asp

Satellite Image of Eruption: http://cimss.ssec.wisc.edu/goes/blog/archives/4513

Iceland Eruption: http://www.youtube.com/watch?v=zXBER2uwepc

Mt. St. Helens Eruption Video (7 min): http://www.youtube.com/watch?v=xP2dreOI8gI

Hawaii Volcano Video (4min):

http://video.nationalgeographic.com/video/environment/environment-natural-disasters/volcanoes/hawaii-volcanoes/

-Two blocks of rock form at a fault - one on top of the other

Hanging wall: the block of rock above the faultFootwall: the block below the fault

FAULT: a break or crack along which rocks move- Rocks on one side of the fault slide past the rocks on the other side of the fault- Movements can be up, down, or sidewaysEARTHQUAKES

Stress can cause either the hanging wall or the footwall to move up or down along a fault

PART 10: EARTHQUAKE QUESTIONS & EPICENTER ACTIVITY

See the Fault Line?

What wall is this?

What wall is this?

REVERSEHanging wall

moved UP relative to the foot wall

NORMALHanging wall moved

DOWN relative to the foot wall

REVERSE THRUST

Hanging wall moved up and

OVER the foot wall

LATERAL2 plates move

horizontally not vertically

TYPES OF PLATE STRESSES

SAN ANDREAS FAULT, CA.

8.2 Measuring Earthquakes

Move up and down like a water waveSlowest wavesTravel at Earth’s surfaceSurface waves cause the most damage.

L-WAVES

- Have the greatest velocity of all earthquake waves

- push (compress) and pull (expand) in the direction that the waves travel

- Travel through solids, liquids, and gases

P-WAVES

- Slower velocity than P-waves

- Shake particles at right angles to the direction that they

travel (side to side movement)

- Travel only through solids

S-WAVES

R-Waves (Rayleigh waves)

TRIANGULATION

Seismic Waves

Why is it important to study earthquakes?

They affect our lives They affect our lives

To better prepare for future earthquakes To better prepare for future earthquakes (improve building technologies)(improve building technologies)

To gather information/data on where they occur, To gather information/data on where they occur, how often, how intense.how often, how intense.

Allow us to obtain information about the Earth’s Allow us to obtain information about the Earth’s interiorinterior

Elastic Rebound Hypothesis

Measuring Earthquakes

Seismographs are instruments that record earthquake waves.

Seismograms are traces of amplified, electronically recorded ground motion made by seismographs.

Measuring Earthquakes

1. Richter Scale (Outdated scale)

• Does not estimate adequately the size of very large earthquakes

• Based on the amplitude of the largest seismic wave

2. Moment Magnitude• Estimates energy released by an earthquake• Derived from the amount of displacement that

occurs along the fault zone • Measures very large earthquakes

LIQUIFACTION

Tilted Victorian home at Howard and 17th Streets in the

Mission District of San Francisco showing liquefaction-related damage from the 1906

earthquake. This area is underlain by marsh deposits

that were covered by artificial fill in the middle to late 1800s.

The earthquake shaking caused the artificial fill to liquefy and lose its ability to support the

house.(Photograph U.S. Geological

Survey)

TSUNAMIS

A tsunami triggered by an earthquake occurs where a slab of the ocean floor is displaced

vertically along a fault.

LANDSLIDES With many earthquakes, the greatest damage

to structures is from landslides and ground subsidence, or the sinking of the ground triggered

by vibrations.

FIRE In the San Francisco earthquake of 1906, most

of the destruction was caused by fires that started when gas and electrical lines were cut.

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GINDEX LINES

What is the contour interval? 20 ft

What is the contour interval?

What is the highest point on the map?

What direction does Equation Creek flow?

Is the slope of the land greater under the

green line or the purple line (lines are the same size!)

20 Feet

859 feet

North

GREEN LINEGREEN LINE

What is the height at point A?

What is the height at point B?

A

B

780 feet

660 feet