SHAPING EARTH’S SURFACE CHAPTER 4 LESSON 2 SHAPING EARTH’S SURFACE

4.2 INFORMATION

NAT GEO: EARTHQUAKES 101

NG: UNDERSTANDING EARTHQUAKES

EARTHQUAKES The vibration caused by the rupture and sudden movement of rocks along a break or a crack in Earth’s crust.

PLATES Large pieces of crust that float on magma in the mantle.

EARTHQUAKES An earthquake can occur at a fault.

FAULT A crack or a fracture in Earth’s crust along which movement occurs.

BONE FRACTURES

FAULT Because of the convection currents beneath tectonic plates …

FAULT … forces build up along faults at plate boundaries.

FAULT RUPTURES When a fault ruptures, Earth’s crust moves along the fault, causing an earthquake.

FAULT RUPTURES Most earthquakes occur at plate boundaries

FOCUS The point in the Earth where an Eartquake starts.

EPICENTER The point on Earth’s surface directly above the focus.

SEISMIC WAVES Waves that carry energy released by an earthquake.

MAGNITUDE The size of an earthquake

The bigger the crack, the stronger the quake

MAGNITUDE Magnitude is determined by how much energy is released during the earthquake.

FAULTS A plate boundary involves more than one fault

FAULTS AND SUBDUCTION Faults are largest where one plate subducts into the mantle …

FAULTS AND SUBDUCTION … and the strongest and most damaging earthquakes occur there.

DR. BINOCS – EARTHQUAKE REVIEW

NG: SEATTLE QUAKE

JAPAN: BUILDING SWAY

EARTHQUAKE ON A BRIDGE