Volcanoes and Earthquakes Review

Volcanoes

• Types of Magma/Lava
  • Composition: Felsic, Intermediate, Mafic, Ultramafic
  • Viscosity: Determines flow and shape of lava
  • Temperature: Influences eruption style
• Plate Tectonics & Bowen's Reaction Series
  • Magma formation at plate boundaries: Divergent and Convergent
  • Bowen's Series explains mineral crystallization in cooling magma
• Predicting Explosivity
  • Gas content and viscosity critical for determining explosivity
  • Assessment of past eruptions helps in prediction
• Magma Composition and Volcano Shape
  • Felsic magma leads to steep stratovolcanoes; Basaltic magma results in broad shield volcanoes
• Dangers of Volcanoes
  • Physical hazards include eruptions, lava flows, pyroclastic flows
  • Some volcanoes more dangerous due to proximity to populated areas or explosive nature
• Volcanic Gases
  • Types: Water vapor, CO2, SO2, H2S
  • More viscous magmas hold more gas, increasing explosion risk
• Eruption Prediction
  • Signs include increased seismic activity, gas emissions, ground deformation
• Climate Alteration
  • Aerosols from eruptions can cool the Earth temporarily
• Greenhouse Gas Impact
  • CO2 and other gases from volcanoes contribute to global warming
• Evacuation Challenges
  • Timing, infrastructure, public communication are essential

Earthquakes

• Relation to Plate Tectonics
  • Strongest quakes at convergent boundaries; weakest at divergent boundaries
• Types of Fault Motion
  • Dip-slip (vertical movement) and strike-slip (horizontal movement)
• Characteristics of Waves
  • Love waves: Oscillate side to side; Rayleigh waves: Rolling motion
• Seismic Measurement
  • Seismographs capture waves; characteristics include amplitude and frequency
• Locating Earthquakes
  • Triangulation using three seismograph stations helps determine epicenter
• Magnitude Scales
  • Richter Scale: Measures energy release; Mercalli Scale: Measures felt intensity and damage

Earthquake Damage and Mitigation

• Structural Damage
  • Buildings experience collapse, cracking due to shaking
• Mitigation Steps
  • Retrofits, enforced building codes, public preparedness training
• Wave Resistance of Buildings
  • Buildings withstand primary and secondary waves best
• Tsunami Dangers
  • Generated by underwater quakes; inundate coastal areas

Mountain Building and Deformation

• Stress and Pressure
  • Stress: Force per unit area; Pressure: Uniform force in all directions
• Rock Response to Stress
  • Brittle: Breaks; Ductile: Deforms without breaking
• Identifying Fault Types
  • Normal faults: Tension; Reverse faults: Compression
• Mountain Formation
  • Caused by tectonic forces; examples: Himalayas from collision of plates

Energy Sources

• Renewable vs Non-renewable
  • Coal, oil, gas: Non-renewable; wind, solar, hydro: Renewable
• Clean Coal
  • Technology aimed at reducing coal's carbon footprint
• Formation of Coal
  • Changes in organic material over millions of years in anoxic environments
• Fracking Explained
  • Technique for extracting oil/gas from rock layers
• Plate Tectonics and Energy
  • Plate movement creates conditions for oil/gas formation

Water Resource Management

• Freshwater Sources
  • Lakes, rivers, aquifers; only 3% of Earth's water is freshwater
• Porosity and Permeability
  • Porosity: Measure of void spaces; Permeability: Ability to transmit fluids
• Groundwater Connection
  • Essential for the water cycle; aquifers are crucial for storage
• Climate Change Impact
  • Alters precipitation patterns affecting water supply

River Systems

• Types of Rivers
  • Braided: Intermingled streams; Meandering: Curved paths with point bars
• Earth's Water Distribution
  • Most of Earth's water is oceanic; fresh water mainly in glaciers and lakes
• River Anatomy
  • Key features: Point bars, cut banks, floodplains
• Stream Flow Calculation
  • Discharge calculated by width, depth, and velocity of the river
• River Morphology
  • Changes due to erosion, sediment deposition, and vegetation

Desert Formation

• Types of Deserts
  • Subtropical, coastal, rain shadow, and polar deserts
• Effect of Circulation Cells
  • Affect wind patterns leading to desert climates
• Coriolis Effect
  • Influences wind directions contributing to desert formation
• Dune Formation
  • Shaped by wind direction and material availability

Glacial Processes

• Glacier Movement
  • Flow due to gravity and basal slip; internal deformation
• Evidence of Glaciation
  • Moraines, striations, and glacially shaped landscapes
• Ice Age Factors
  • Climate changes guided by orbital variations and plate tectonics.