Locating Plate Boundaries of the Pacific Rim Around the Ring of Fire.
Pacific Ring of Fire and Natural Disasters. Pacific Ring of Fire The “Ring of Fire” is a series...
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Transcript of Pacific Ring of Fire and Natural Disasters. Pacific Ring of Fire The “Ring of Fire” is a series...
Pacific Ring of Fire and Natural Disasters
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)
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
Where?
Earthquakes occur at two different plate boundaries
Subduction Zones
Plates colliding into each other
Transform Faults
Plates sliding past each other
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)
What is a volcano?
An opening in the earth’s crust where magma (molten rock) flows from the mantle to the surface
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)
Classifying Volcanoes
• Shield
• Intermittent
• Dormant
• Composite or Stratovolcano
• Extinct
Constan
t
• Active
Shield VolcanoesA 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
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
Mt. St. Helens: Before and After
Pavlov - Alaska
Mount Ontake - Japan
Sarychev - Russia
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