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The Earth Science tradition in G

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The Earth Science tradition in G Powered By Docstoc
					Earth Science tradition
  Focuses on processes that create
  environments significant to humans.
- How have Earth components been
  formed?
- How do they change; what is likely to
  bring about future changes?
- How are environmental features related to
  past, present, future human use of Earth?
Earth forces
 Tectonic forces.
 Gradational processes.
Plate tectonics
 Accounts for continental drift, seafloor
 spreading, movement of lithospheric
 plates, and deformation of Earth’s crust.
Subduction
 Plates with different types of crust push
 against each other, denser oceanic crust is
 forced down into the asthenosphere.
December 26, 2004




   Location map of Indonesia from the National Earthquake Information Center
              (http://neic.usgs.gov/neis/bulletin/neic_slav_l.html)
                                               Earthquake caused by
                                               subduction of Indian plate
                                               beneath the Burma
                                               microplate.



                                                Relative motion of Indian
                                                plate to Burma microplate =
                                                0.06 m per year (2.4 inches
                                                per year).




Tectonic Setting of Earthquake of 26 December 2004 from United States Geological Survey
                  (http://earthquake.usgs.gov/eqinthenews/2004/usslav/)
Areas potentially affected by tsunami inundation and run-
up in yellow (i.e. shore zones < 20 m above sea-level)




          Areas Potentially Affected by Tsunami of 26 December 2004 from UNOSAT
                                      (www.unosat.org)
Predicted Arrival Time of First Tsunami Wave (in hours after earthquake)
Countries Reporting Casualties from
Earthquake and Tsunami
   Indonesia
   Thailand
   Andaman Islands (India)
   Nicobar Islands (India)
   Myanmar
   Bangladesh
   India
   Sri Lanka
   The Maldives
   The Seychelles
   Kenya
   Somalia
   Tanzania

   In addition, many western nations reported fatalities and missing
   among tourists who were visiting the affected countries.
Events known to generate tsunamis
   Submarine earthquakes
   Explosive volcanic eruptions
   Submarine landslides
   Terrestrial landslides that enter water
   Impacts of large extraterrestrial objects
   (e.g. asteroids or comets) in the ocean.
Other earthquake-generated
tsunamis
  Great Chilean quake and tsunami, 1960
  (largest quake ever recorded, 9.5),
  devastated Pacific Rim.
  Good Friday quake, Anchorage, Alaska,
  1964 (9.2) devastated coastal Alaska
  and Crescent City, California.
Krakatau, August 1883
 Triggered by explosive volcanic eruption.
 Among most violent eruptions in last 200 years.
 Destroyed 165 coastal Indonesian villages on
 Java and Sumatra – approx. 36,000 fatalities.
 Prior to December 2004, most destructive
 tsunami on record.
Earthquake prediction
 Property value changes.
 Reduced availability of insurance,
 mortgages, investment.
 Temporary/permanent population
 relocation.
 Decline in employment.
 Reduction in public services.
Earth materials
  Vary as to mineral composition:
  - igneous
  - sedimentary
  - metamorphic
 Rocks as constituent
 ingredients of landforms
  Strength, permeability, chemical content
  control how rocks respond to:
- tectonic forces building landforms,
- gradational processes wearing landforms
  away.

				
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