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TSUNAMI GENERATION MECHANISMS

TSUNAMI GENERATION MECHANISMS. Earthquake Parameters. Moment measures earthquake strength. Mechanism specifies the orientation of the earthquake fault and the direction of slip on it. Earthquake depth :deep earthquakes would produce less potent tsunamis than similar shallow earthquakes.

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TSUNAMI GENERATION MECHANISMS

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  1. TSUNAMI GENERATION MECHANISMS

  2. Earthquake Parameters • Moment measures earthquake strength. • Mechanism specifies the orientation of the earthquake fault and the direction of slip on it. • Earthquake depth :deep earthquakes would produce less potent tsunamis than similar shallow earthquakes.

  3. Earthquake Zones

  4. Faults: Strike Slip

  5. Faults: Dip Slip

  6. Faults: Dip Slip

  7. Fault Structures - Normal Faults

  8. Fault Structures - Reverse Faults

  9. Faults: Strike Slip

  10. Pull Apart Mechanism

  11. NASA How does the earthquake generate tsunami? Imagine a fist rising up from under the water. Water rolls down off the sides of the fist. When the bottom of the ocean was deformed by this megathrust quake, the upward force acted like that fist, creating massive waves of tsunamis, which spread out in all directions.

  12. EARTHQUAKE INITIATION Synthetic record sections of vertical tsunami motions at distances of 200, 500, 1000 and 2000km from point dip slip (top) and strike slip (bottom) earthquakes of magnitude Mw=7.5 and depth 10 km. Time runs for five hours and the peak amplitude of each trace is given in cm at the right. The lower half of the focal sphere and azimuth of observation are shown toward the right (Stewe Ward, Encyclopedia of Physical Science and Technology)

  13. Volcanic Eruptions

  14. Animation

  15. Submarine Landslide

  16. Scientific terms: • Run-up:Vertical height a wave reaches above a reference sea level as it washes ashore. • Wave height:Vertical measurement of the wave before it reaches shore. • Inundation distance: Horizontal distance a tsunami reaches landward from shoreline.

  17. USGS-NEIC

  18. Appearance of a tsunami when reaches the shore • A rapidly rising or falling tide • A series of waves • A bore

  19. Run-up height: • Tsunamis of distant origin: > 50 ft (15 m) • Tsunami generated near the earthquake epicenter: > 100 ft (30 m) • First wave may not be the largest in the series of waves.

  20. Do tsunamis stop once on land? • Energy reflection back • Edge waves

  21. Complicated behavior of tsunami waves near the coast ! • The first run-up of a tsunami is often not the largest. • Do not return to a beach several hours after a tsunami hits.

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