Geology of Costa Rica
Geologic Hazards
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Earthquakes
Tsunami
Volcanism
Slope Hazards
Earthquake Safety
• You may well experience an earthquake
• Earthquakes don’t kill people; Buildings kill
people
• We will not be in high risk settings
• Minor shaking: no hazard
• Major or prolonged shaking: Get outside
• Avoid buildings and power lines
• Trees are well engineered seismically
• If inside, get under something sturdy or brace in
a doorway.
Tsunamis
• Warning Signs
– Strong earthquake on coast
– Abrupt changes in sea level – up or down
• Get to high ground or inland immediately
• Do not pass Go, do not collect $200
Volcanism
• We will not go anywhere near active
volcanoes or known hazardous areas.
• If activity occurs, we will evacuate
immediately
• I am a volcano expert. If you see me
running, try to catch up.
Slope Hazards
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Landslides due to earthquakes
Mudflows due to heavy rains
Get out of the way
Get off slope if you sense movement
Get away from streams if water level starts
to rise
Rips
• When waves break parallel to a beach,
rips occur
Rips, Lake Superior
Oblique Rips
A Subduction Zone
How Arcs Grow
Exotic Terranes
Fit of
Continents
Across the
Atlantic
The Caribbean
Opening of the North Atlantic
Yucatan Rifts Away
Volcanic Plateau Begins to Form
Plateau Encounters Subduction Zone
Yucatan Basin Opens
East Pacific Rise Approaches
Now
Serpentinite
Bedded Chert
Pillow Lava
Pillow Lava
Graywacke
Flysch