Natural Disasters
Natural disasters are severe natural events that cause widespread damage. Understanding them helps communities prepare and respond effectively.
Earthquakes
Caused by movement along tectonic plate boundaries. Energy releases as seismic waves. Measured on the Moment Magnitude Scale (MMS). Major quakes occur along the "Ring of Fire" around the Pacific Ocean.
Volcanoes
Openings in Earth's crust where magma (lava), ash, and gases escape. Types:
• Shield volcanoes — broad, gentle slopes (Hawaii)
• Stratovolcanoes — steep, explosive (Mt. St. Helens, Mt. Fuji)
Located mostly near plate boundaries.
Hurricanes, Typhoons & Cyclones
Tropical storms with sustained winds >74 mph. Same storm type — different regional names. Powered by warm ocean water. Damage from wind, storm surge, and flooding. Category 1–5 (Saffir-Simpson scale).
Tornadoes
Violently rotating columns of air extending from storm cloud to ground. Most powerful on Earth (EF5 >200 mph winds). "Tornado Alley" in US Great Plains is most prone area.
Tsunamis
Series of massive ocean waves triggered by undersea earthquakes, volcanic eruptions, or landslides. Travel at 500–800 km/h in open ocean (as fast as a jet!). 2004 Indian Ocean tsunami killed ~230,000 people.
Preparedness
Earthquake: drop, cover, hold. Hurricane: evacuate early. Tornado: move to lowest interior room. Tsunami: move to high ground immediately. An early warning system saves lives.
FAQ
Where do most earthquakes happen? Along tectonic plate boundaries, especially the Ring of Fire surrounding the Pacific Ocean.
Quick Quiz
Test what you just learned. Choose the best answer for each question.