1. Pacific Ring of Fire and Natural Disasters

3. Pacific Ring of Fire  The “Ring of Fire” is a series of tectonic plate boundaries around the pacific ocean.  75% of the worlds volcanoes (450 +) and 90% of the worlds earthquakes occur here.  Mariana’s Trench = deepest place on earth (Challenger Deep is 36,000 ft, 7000 ft. taller than Mt. Everest)

5. What is an earthquake?  A release of energy caused by the sudden movement of tectonics plates  The energy is released as “seismic waves”  Like ripples in a pond

6. Where?  Earthquakes occur at two different plate boundaries  Subduction Zones  Plates colliding into each other  Transform Faults  Plates sliding past each other

8. Measuring Earthquakes… July 1976, China – 243,000 (7.8) Dec. 2004, Indian Ocean – 230,000 (9.1-9.6) 1960, Chile – 20,000 homeless (9.5) 1964, Alaska - 132 (9.2) 2011, Japan – 16,000 (9.0) 2010, Chile – 120 (8.8)

9. What is a volcano? An opening in the earth’s crust where magma (molten rock) flows from the mantle to the surface

10. Volcanoes and Tectonic Plates Most volcanoes occur near tectonic “active zones” Divergent zones – where two plates are moving away from each other (Katla volcano in Iceland) Subduction zones – where two plates are crashing into each other (Kyushu volcano in Japan)

11. Classifying Volcanoes Shield IntermittentDormant Composite or Stratovolcano Extinct Active

12. Shield Volcanoes A shield volcano is a large, gently sloped volcano made up from many slow, steady flows of hot lava. Low and broad – like a warrior’s shield. Materials Erupted : mainly liquid lava, so the volcano is made of layers of hardened lava. Non-explosive eruptions Example: the volcanoes of Hawaii

13. Composite or Stratovolcano A composite volcano is a huge mountain-like volcano. Layers build up like frosting on a cake forming a cone with steep sides. Materials Erupted: sometimes lava, sometimes rock fragments. May have very explosive eruptions Example: Mount St. Helens

14. Mt. St. Helens: Before and After

15. Pavlov - Alaska Mount Ontake - Japan Sarychev - Russia

16. Erupting volcanoes can destroy land, plants, animals and human settlements Volcanic eruptions include:  Earthquakes  Lava flows  Explosions of hot gas, ash and rock  Landslides and mudslides Volcanoes also create land and life Creating land  when molten lava cools and solidifies, it turns into solid rock (this is new land) Creating life  the minerals from volcanic rock and ash create very good soil for new plants Because of this balance of creation and destruction, people often say eruptions mark the “re-birth” of an environment