What's your question?
  1. A tsunami is not a single wave but a series of waves caused by the displacement of a large volume of water. When an undersea earthquake occurs at a subduction zone, the seafloor snaps upward or downward, pushing the water column above it. This creates a wave that can travel across entire oceans at sRead more

    A tsunami is not a single wave but a series of waves caused by the displacement of a large volume of water. When an undersea earthquake occurs at a subduction zone, the seafloor snaps upward or downward, pushing the water column above it. This creates a wave that can travel across entire oceans at speeds exceeding 800 km/h (speed of a jet plane). Unlike normal tide-driven waves, tsunamis have extremely long wavelengths. As they approach the shore, the front of the wave slows down due to friction with the seabed, causing the back of the wave to pile up, resulting in a surge that can penetrate kilometers inland.

    See less
    • 31
  2. While volcanic eruptions or underwater landslides can cause tsunamis, approximately 80% to 90% are triggered by seismic activity. For a tsunami to occur, the earthquake must be of high magnitude (usually above 7.0) and must involve vertical movement of the crust. Horizontal (strike-slip) earthquakesRead more

    While volcanic eruptions or underwater landslides can cause tsunamis, approximately 80% to 90% are triggered by seismic activity. For a tsunami to occur, the earthquake must be of high magnitude (usually above 7.0) and must involve vertical movement of the crust. Horizontal (strike-slip) earthquakes, like those on the San Andreas Fault, rarely cause tsunamis because they don’t displace the water upwards. The sudden “rebound” of the overriding plate at a subduction trench acts like a giant paddle, pushing the ocean and creating a wave that carries immense energy across thousands of miles.

    See less
    • 44
  3. The Ring of Fire is home to the world's most dangerous subduction zones. Here, the Pacific Plate is constantly colliding with and sliding beneath surrounding plates like the Eurasian, North American and Philippine plates. This constant grinding and subduction build up massive amounts of elastic straRead more

    The Ring of Fire is home to the world’s most dangerous subduction zones. Here, the Pacific Plate is constantly colliding with and sliding beneath surrounding plates like the Eurasian, North American and Philippine plates. This constant grinding and subduction build up massive amounts of elastic strain, leading to frequent and high-magnitude earthquakes. Countries along this belt, such as Japan, Chile, the Philippines and the western United States (Alaska and California), are at constant risk. This zone also contains about 75% of the world’s active volcanoes, illustrating the intense tectonic and magmatic activity that defines this “circum-Pacific” horseshoe-shaped region.

    See less
    • 23
  4. When an earthquake affects the oceanic crust, the resulting water displacement creates a wave with a wavelength that can be over 100 kilometers long. In the open ocean, these waves are barely noticeable to ships because their height is low. However, they possess a "deep-water" energy that extends toRead more

    When an earthquake affects the oceanic crust, the resulting water displacement creates a wave with a wavelength that can be over 100 kilometers long. In the open ocean, these waves are barely noticeable to ships because their height is low. However, they possess a “deep-water” energy that extends to the seafloor. As this energy enters the shallow continental shelf, “shoaling” occurs—the wave height increases dramatically while the speed drops. This results in a “Tsunami,” a destructive surge that can wash away entire coastal cities, as seen in the catastrophic 2004 Indian Ocean and 2011 Tohoku events.

    See less
    • 61
  5. Japan's location on the "Ring of Fire" makes it one of the most tsunami-prone nations in the world. Because the waves have such long wavelengths, they are almost invisible in the deep sea; fishermen would be out in the ocean and not notice anything unusual, only to return home and find their coastalRead more

    Japan’s location on the “Ring of Fire” makes it one of the most tsunami-prone nations in the world. Because the waves have such long wavelengths, they are almost invisible in the deep sea; fishermen would be out in the ocean and not notice anything unusual, only to return home and find their coastal villages destroyed. This led to the specific name “harbor wave.” The term was adopted into English and international scientific communities in the 20th century to distinguish these seismically triggered waves from “tidal waves,” which are caused by the gravitational pull of the moon and sun.

    See less
    • 22