Earthquakes and Faults

Earthquakes and Faults

• Earthquake: Rapid release of energy causing Earth's vibration, and ground shaking from fault movement.
• Fault: Crack in Earth's crust with rock movement along it.
• Fault Types: Reverse, normal, strike-slip, oblique.
• Elastic Rebound Theory: Explains energy storage and release causing fault movement.
• Active Faults: Show earthquake activity within the past 10,000 years.
• Inactive Faults: Show no recent earthquake activity.
• Fault Movement Effects: Strong ground motion, landslides, rockfalls, ground ruptures.
• Focus (Hypocenter): Point inside Earth where seismic waves originate.
• Epicenter: Location on Earth's surface above the focus.
• Shallow-Focus Earthquakes: Occur within 100 km of the surface; more destructive.
• Deep-Focus Earthquakes: Rare, less than 3% of earthquakes.
• Earthquake Hazards: Tsunamis from underwater fault movements.

Seismic Waves and Earth's Layers

• Seismic Waves: Energy from the focus causing earthquakes; used to study Earth's interior.
• Body Waves: Travel through Earth's interior.
  • P-Waves: Fastest, travel through solids, liquids, and gases.
  • S-Waves: Slower, travel only through solids.
• Surface Waves: Travel along Earth's surface.
  • Love Waves: Horizontal ground motion, damages building foundations.
  • Rayleigh Waves: Ripple-like motion, similar to ocean waves.
• Wave Travel Insights: P-wave velocity decreases in liquids. S-waves do not pass through the outer core (liquid).

Typhoons and Weather Phenomena

• Tropical Cyclones: Systems of thunderstorms with spiral clouds.
  • Types: Typhoons (Northwest Pacific), Hurricanes (North Atlantic/Eastern Pacific), Cyclones (Indian Ocean/Bay of Bengal).
• Typhoon Impacts: Strong winds, heavy rain, floods, landslides, storm surges, tornadoes.
• PAR (Philippine Area of Responsibility): Region monitored by PAGASA for typhoons.
• Intertropical Convergence Zone (ITCZ): Area near the equator where trade winds meet, forming cyclones.
• Storm Surge: Abnormal sea-level rise from tropical cyclones.
• Typhoon Tracking: 5-7 day predictions of movement and strength.
• Factors Weakening Cyclones: Land interaction (e.g., Sierra Madre), cold water.
• Public Storm Warning Signals: Alerts about incoming disturbances.

Solar System and Celestial Objects

• Comets: "Dirty snowballs" of ice, dust, and metals. Develop tails near the sun (gas and dust pushed by solar wind).
  • Origins: Kuiper Belt (short-period comets), Oort Cloud (long-period comets).
• Asteroids: Minor planets originating from the asteroid belt between Mars and Jupiter.
• Meteoroids, Meteors, Meteorites:
  • Meteoroid: Space debris.
  • Meteor: Streak of light from a meteoroid burning up in the atmosphere.
  • Meteorite: Meteoroid surviving and hitting Earth.
  • Fireballs: Bright meteors; exploding fireballs called bolides.