PLANET EARTH CH. 21

LAYERS Crust Mantle Outer Core Inner Core

Crust Hard, solid rock Continental (thicker) & oceanic (thinner) Mantle Mostly solid & rigid At deeper levels, very hot & plastic (soft & deformable, like gum)

Outer Core Mainly iron (Fe) & nickel (Ni) Liquid due to high temperature Inner Core Also Fe & Ni Solid because huge pressure forces the atoms together

Continental Drift Theory Alfred Wegener The Origins of the Continents and Oceans Continent “puzzle pieces” fit together “PANGAEA” Fossil & rock evidence

PROBLEM: Did not explain the movement of continents

Plate Tectonics Lithosphere – crust & upper mantle 9 large & several small pieces Moved by convection currents in the asthenosphere (deeper mantle)?

Plate Boundaries Divergent – moving apart Mid-ocean ridges Convergent – moving together Subduction (NA & Pacific) Mountains & volcanoes (Everest & Himalayas) Transform Fault Earthquakes (California)

Earthquakes Vibrations from rock rubbing together d. focus – exact point inside Earth where an earthquake happens d. epicenter – point on Earth’s surface directly above the focus

E’quakes – 1973-Mar. 2011

Seismic waves Surface – cause surface damage Primary (P) – longitudinal (slinky or spring) Secondary (S) – transverse (rope) Richter scale

d. volcano – an opening in Earth’s crust through which magma emerges; also called vents Shield (Mauna Loa) Composite/Strato (Mt. Fuji, Mt. St. Helen’s) Cinder cone (Parícutin)

Parinacota, Chile/Bolivia

Lassen Volcanic Park, NM

Mount Belknap, OR

Mapping the Surface Latitude: measures distance from equator N/S like a “ladder” going up & down Longitude: measures distance from Prime Meridian E/W What’s that? What’s the international date line? Time zones?

Mapping the Surface