EARTHQUAKE APR12

Focus

Focus

the point inside the Earth where an earthquake begins

Convergent Boundary

The boundary formed by the collision of two lithospheric plates(mountain building)

Divergent Boundary

Boundary created when two plates pull apart from each otherresulting in an opening between the plates where magma rises and cools (creates new crust)

Epicenter

The point on the earth's surface that corresponds to the location in the earth where an earthquake begins

Lithosphere

The rigid outer layer of earthincluding the crust and upper mantle

Magnitude

The measurement of an Earthquake's strength based on seismic waves and movement along faults

P-waves

the fastest type of seismic wave; can travel through solids and liquids

S-waves

called secondary waves or shear wavestravels slower

Plate Tectonics

the theory called secondary waves or shear waves driven by convection currents in the mantle

Subduction

a process by which mountains can form ( oceanic plate dives beneath a continental plate)

Transform Boundary

boundary formed where two lithpospheric plates slide past each other

Fault

a crack in the earth's crust along which rock moves

Folding

bending or curving of earth's crust

Seismograph

an instrument that records earthquake waves

Hotspot

A volcanically active area of Earth's surface commonly far from a tectonic plate boundary.

Surface Wave

A seismic wave that travels

along the surface of the earth

Landslide

The shaking or sliding of ground triggered by vibrations from the earthquake

Asthenosphere

A weak plastic layer of the mantle below the lithosphere

Loma Prieta Earthquake

The 1989 earthquake that caused major damage in San Francisco and Oakland

1906

The year the San Andreas fault moved 8 feet in Marin county

Liquefaction

Solis saturated with water are turned into liquid after a eartgquake

Richter Scale

A scale that measures the magnitude of earthquakes 0.0 -9.0