Causes of Tsunamis
Size of a Tsunami
-Can have a wavelength hundreds of miles long
-Grow larger as they approach shore
-Can exceed 100 ft tall
-Can affect the coastal shores more than a mile inland
-Caused by a large and sudden displacement of the ocean
-Earthquakes are the most common cause (88%)
-Landslides, volcanic activity and even asteroids can also cause tsunamis
Speed of a Tsunami
Location of Tsunamis
Tsunamis Duration
-Depends on depth of water it is traveling through
-Can move as fast as a jet plane
-Closer to shore, the slower the speed
-Tsunamis are capable of occurring in any body of water
-Most occur within the "Ring of Fire"
-Japan has experienced the highest percentage of tsunamis in the world
-Large tsunamis can continue for days
-Time between crests can range from 5 min to 2 hours
-Dangerous currents can last for days!!
Tsunamis
Structure of a Tsunami
Tsunami Waves
vs.
Ocean Waves
Detection of Tsunamis
Ocean Waves
-Generated by wind
-Affect ocean surface
-Slow
-Measured in feet
Tsunami Waves
-Generated by displacement of water
-Travel through water column
-Fast
-Measured in miles
-Referred to as the "wave train"
-Not simply one big wave
-Made of multiple waves of all sizes
-Rely on seismic and water level networks
-Seismic networks provide information about earthquakes
-Water level networks provide information about changes in water level
Tsunamis are:
-Powereful and destructive
-very long waves
-able to move across entire ocean basins
Steps to Prepare for a Tsunami
Step 1: Educate yourself about tsunamis and warning
Step 2: Make an emergency plan
Step 3: Map out evacuation routes and practice them
Step 4: Put together a disaster kit
Step 5: Be a role model by sharing plans and knowledge with others
Danger!
-Tsunamis are very powerful and destructive
-Strong currents that can last for days
-Rapid flooding
-Destroys homes, natural resources etc.
Earthquakes and Their Effect on Tsunamis
Tsunamis
-Provide the energy to generate tsunamis
-Occur in earthquakes with a magnitude above 7.0
-Occur at subduction zones
-Earthquakes can cause landslides