Earth's Dynamic Systems: Geology, Hydrology, and Atmosphere

Ancient Earth and Continental Drift

Pangea and Panthalassa

• The great continent Pangea (Pangaea) and the superocean Panthalassa.
• The ocean later divided into Laurasia and Gondwana.

Seismicity and Earthquakes

Understanding Seismic Waves

• Seismic waves originate at the focus or hypocenter.
• The epicenter is the point on the Earth's surface directly above the hypocenter.

Types of Seismic Waves

• P-waves (Primary waves):
  • Longitudinal waves.
  • Pass through solids, liquids, and gases.
• S-waves (Secondary waves):
  • Transverse waves.
  • Are slower than P-waves.
• L-waves (Love waves/Surface waves):
  • Propagate in circles along the surface.

Measuring Earthquake Intensity

• Earthquake magnitude is measured using the Richter scale.
• Earthquake intensity (perceived effects) is measured using the Mercalli scale.

Hydrology and Water Systems

Environmental Concerns

• Loss of vegetation cover on the planet leads to significant erosion.
• Limiting water infiltration in Mexico due to widespread pavement.

Rivers and Dams

• The Manuel Moreno Torres Dam is located on the Grijalva River.

Lakes: Features and Types

• Features:
  • Can contain fresh or salt water.
  • Vary in extension and distance from the sea.
  • Many are of glacial origin.
• Types:
  • Tectonic
  • Barrier
  • Crater
  • Glacial
  • Endorheic
  • Pelagic
• Causes of Misuse: Human impact and disappearance.

Oxbow Lakes

• An oxbow lake is formed when winding rivers change course, leaving one of the meanders isolated.

Groundwater and Aquifers

• Groundwater Formation: Water and air are found in underground aquifers.
• Glacial Influence: Deep infiltration occurred in glaciers that covered large parts of the planet during the Cenozoic era. This was important for lake formation and generated much wildlife.

Notable Glacial Lakes

• The Great Lakes (e.g., Superior, Erie) were formed by glacial erosion.

Earth's Atmosphere

Atmospheric Role and Shape

• The gaseous atmosphere surrounding the Earth helps to protect life.
• It prevents meteorites from reaching the surface.
• It gives rise to the climate and the hydrologic cycle.
• Its shape is a geoid.

Atmospheric Composition

• Nitrogen: 78%
• Oxygen: 21%
• Argon: 0.93%
• Carbon Dioxide: 0.04%
• Other noble gases.
• Convective movements occur within the atmosphere.

Physical Properties of Air

• Compressibility: When air is cold, it compresses.
• Expandability: When air is hot, it expands.
• Diathermancy: The atmosphere allows sunlight to pass through but absorbs heat.
• Other properties: Tasteless, odorless, and colorless.

Chemical Properties of Air

• Sound conductive.
• Oxidizer: Oxidizes things.
• Supports combustion.

Active Layers of the Atmosphere

• Troposphere: (Aircraft, meteorological phenomena)
• Stratosphere: (Jet propulsion)
• Mesosphere: (Meteorites, spacecraft burn up)
• Ionosphere: (Auroras)
• Exosphere: (Outermost layer)

Weather

Weather refers to the state of the atmosphere at a given time and place.