Earthquakes

Two types of crust “float” on the upper mantle:

• oceanic crust (heavier, sinks lower)

• continental crust (lighter, floats higher)

Three types of plate convergence

• oceanic – continental

• oceanic – oceanic

• continental - continental

Oceanic – continental plate convergence

Nazca plate – South America plate

Oceanic – oceanic plate convergence

New Hebrides Trench near Vanuatu

Continental – continental plate convergence India/Eurasia plate collision (forms Himalayan Mountains)

Earthquake Motion

Historical seismic activity in Canada

1906 San Francisco Earthquake

Mercalli Richter

1964 Alaska earthquake damage map: modified Mercalli scale

III - IV

VVIVII

VIII - X

Liquefaction and slumpingAnchorage, Alaska - 1964

Earthquake-proof buildings

Is a major earthquake in California, Alaska or Japan of any concern thousands of kilometers away, in Hawaii?

Tsunami (seismic wave)

The power of a tsunami