Seismic Waves Pwaves also called primary or compressional

Seismic Waves § P-waves - also called primary or compressional waves (push/pull)

P-Waves

P-Wave Damage

Seismic Waves § S-waves- also called secondary or shear waves

S-Waves

S-Wave Damage

S-Waves

Seismic Waves

Seismic Waves

Locating Earthquake Epicenter

Locating Earthquake Epicenter

Locating Earthquake Epicenter

Locating Earthquake Epicenter

Locating Earthquake Epicenter

Atmosphere

Atmosphere § The mixture of gases that surrounds Earth § Nitrogen, oxygen, carbon dioxide, and other gases are all parts of this mixture § These gases are constantly added and removed

Composition of the Atmosphere § 78% Nitrogen § 21% Oxygen § Other gases including argon, carbon dioxide, methane, and water vapor make up the rest of the atmosphere

Not just gases § The atmosphere also contains atmospheric dust (many types of tiny, solid particles) in addition to gases. § Atmospheric dust can include: • • • Soil Salt Ash Pollen Bacteria and viruses Aerosols – tiny liquid droplets

Layers of the Atmosphere § Four layers: • • Troposphere Stratosphere Mesosphere Thermosphere

Troposphere § The atmospheric layer nearest the surface of the Earth § It extends to 18 km above Earth’s surface

Stratosphere § The layer above the troposphere § Where the ozone layer is located

Mesosphere § The layer above the stratosphere § Extends to an altitude of about 80 km

Thermosphere § Layer of the atmosphere furthest from Earth’s surface

Temperature in the Atmosphere

Energy and Heating § Three mechanisms transfer energy from the sun: • Radiation • Convection • Conduction

Energy and Heating § Radiation - the transfer of energy across space and in the atmosphere § Convection - the transfer of heat by air currents. Hot air rises and cold air sinks. § Conduction - the flow of heat from a warmer object to a colder object when the objects are placed in direct physical contact

Heating Earth § Our planet only receives about two-billionths of the sun’s energy § About half the energy that reaches the atmosphere will pass though to Earth’s surface § The rest is absorbed or reflected in the atmosphere by clouds, gases, and dust, or by the Earth’s surface § Oceans and land radiate energy back into the atmosphere – so the Earth doesn’t overheat!

Greenhouse Gases Warm the Lower Atmosphere § Greenhouse gases • • H 2 O CO 2 CH 4 N 2 O § Greenhouse effect § Human-enhanced global warming

The Greenhouse Effect

The Greenhouse Effect § The greenhouse effect : § Without the greenhouse effect, the Earth would be too cold for life to exist.

Flow of Energy to and from the Earth