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Tsunami generation requires the sudden displacement of water. Tsunami initiation events include: Earthquakes , particularly normal or reverse (thrust) faulting where displacement along the fault is up-down
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Tsunami generation requires the sudden displacement of water. Tsunami initiation events include: • Earthquakes, particularly normal or reverse (thrust) faulting where displacement along the fault is up-down • Submarine slump, usually (but not always) initiated by an earthquake. GREATEST TSUNAMI HAZARD TO THE UNITED STATES • Volcanic eruptions, particularly those involving submarine volcanic explosions and/or caldera collapse. Krakatau, 1883 • Landslide or Rockfall • Prehistoric, but with ample geological evidence: • 6) Volcanic Flank Collapse (Hawaii, Canary Islands) • 7) Meteorite Impact
Chilean Earthquake May 1960 • (Largest earthquake in recorded history M = 9.5): • Hilo, Hawaii: wave refraction focuses energy into the bay • Onagawa, Japan: example of “Trough first”
Submarine slump, usually (but not always) initiated by an earthquake. GREATEST TSUNAMI HAZARD TO THE UNITED STATES • Sediment on the edge of steep continental slope, particularly near trenches and submarine canyons, can be mobilized into a submarine slide. • Examples: • Papua, New Guinea, 1998 • -3 waves of 14 meters kill 2,500 people after moderate earthquake (Richter 7) • 2) Nicaragua, September 1992: Richter 7 caused tsunami with runup of 10 meters. Seafloor survey conducted afterward showed slide “scars” • Both examples near subduction zone, so these may be thrust fault generated like Indonesia, but…
Tsunami generation requires the sudden displacement of water. Tsunami initiation events include: • Earthquakes, particularly normal or reverse (thrust) faulting where displacement along the fault is up-down • Submarine slump, usually (but not always) initiated by an earthquake. GREATEST TSUNAMI HAZARD TO THE UNITED STATES • Volcanic eruptions, particularly those involving submarine volcanic explosions and/or caldera collapse. Krakatau, 1883 • Landslide or Rockfall • Prehistoric, but with ample geological evidence: • 6) Volcanic Flank Collapse (Hawaii, Canary Islands) • 7) Meteorite Impact