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  • Earthquakes of the 20th Century

    3,233 views 4 days ago
    This animation shows every recorded earthquake in sequence as they occurred from January 1, 1901, through December 31, 2000, at a rate of 1 year per second. The earthquake hypocenters first appear as flashes then remain as colored circles before shrinking with time so as not to obscure subsequent earthquakes. The size of the circle represents the earthquake magnitude while the color represents its depth within the earth. At the end of the animation it will first show all quakes in this 100-year period. Next, it will show only those earthquakes greater than magnitude 6.5, the smallest earthquake size known to make a tsunami. It will then show only those earthquakes with magnitudes of 8.0 or larger, the “great” earthquakes most likely to pose a tsunami threat when they occur under the ocean or near a coastline and when they are shallow within the earth (less than 100 km or 60 mi. deep). The animation concludes by showing the plate boundary faults responsible for the majority of all of these earthquakes.

    The era of modern earthquake seismology—the scientific study of earthquakes—began in the 20th Century with the invention of the seismometer and its deployment in instrument networks to record and measure earthquakes as they occur. Therefore, when the animation begins only the largest earthquakes appear as they were the only ones that could be detected at great distances with the few available instruments available at the time. But as time progresses, more and more seismometers were deployed and smaller and smaller earthquakes could be recorded. For example, note how in the 1930’s many small earthquakes suddenly seem to appear in California, but this illusion results from the installation of more and more instruments in that region. Likewise, there appears to be a jump in the number of earthquakes globally in the 1970’s when seismology took another leap forward with advances in telecommunications and signal processing with digital computers, a trend that continues today.

    20th Century seismology revealed the global geographic distribution of earthquakes and helped to solidify the Theory of Plate Tectonics. Notice how earthquake epicenters do not occur randomly in space but form patterns over the earth’s surface, revealing the boundaries between tectonic plates as shown toward the end of this animation. This time period also includes some remarkable events, including those that generated devastating tsunamis:

    8.8 — Ecuador — 31January 1906
    8.4 — Kamchatka, Russia — 3 February 1923
    8.4 — Sanriku, Japan — 2 March 1933
    8.6 — Unimak Island, Aleutian Islands — 1 April 1946
    9.0 — Kamchatka, Russia — 4 November 1952
    8.6 — Andreanof Islands, Aleutian Islands — 9 March 1957
    9.5 — Valdivia, Chile — 22 May 1960
    9.2 — Prince William Sound, Alaska — 28 March 1964
    8.7 — Rat Islands, Aleutian Islands — 4 February 1965

    These earthquakes represent some of the largest ever recorded. Note how they all occur at a particular type of plate boundary, subduction zones where tectonic plates collide, so these are the regions where we expect future devastating tsunamis to be generated. Show less
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  • PTWS: Tsunami Warning! Play all

    When a major undersea earthquake occurs near the coast, a destructive tsunami can result that will hit near-by coasts in minutes and also travel across entire oceans causing damage 1000’s of kilometers away and up to 24 hours later. To alert far-away coasts, internationally coordinated tsunami early warning systems, such as the Pacific Tsunami Warning and Mitigation System (PTWS), have been established to quickly provide tsunami threat information to countries.

    2015 marks the 50th year of the PTWS. The System was established in 1965 in response to the 1960 M9.5 earthquake off South-central Chile that generated a tsunami which crossed the Pacific killing hundreds in Hawaii, Japan, and the Philippines. The PTWS has been built up over the decades through international cooperation and the contributions of countries and organizations under the UNESCO IOC framework.

    To sustain awareness on the dangers of tsunamis, and to educate the public on how the PTWS works to disseminate alerts on approaching tsunami, the ITIC, in cooperation with Chile, has produced a 6-minute outreach video. The aim of the video is to strengthen public and stake-holder agency knowledge of, and confidence in, tsunami alerts that save lives and reduce property damage.

    This video chronicles the tsunami warning chain for a M9.5 earthquake off Northern Chile as Pacific Tsunami Warning Center (PTWC) staff quickly analyze seismic and sea level data, forecast tsunami wave heights, and disseminate their threat assessments to country National Tsunami Warning Centers around the Pacific. Woven into this fast-paced video are vignettes highlighting tsunami warning and emergency response actions by centers and communities starting immediately after the earthquake in Chile and Peru, and after receiving the PTWC alerts in Samoa and Hawaii, and in Australia, Japan, Indonesia, and the Philippines.
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  • Hawaii DOD Public Affairs - Tsunami Awareness Month Play all

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  • How a Tsunami Warning Center Works Play all

    • A Decade of Tsunami Warning System Sensor Network Upgrades - Duration: 4 minutes, 9 seconds.

      • 3 years ago
      • 7,675 views
      The best-known tsunami-detection devices are the DART buoys. These buoys transmit data from their pressure sensors on the sea floor that measure tsunami waves passing over them. In 2004 we had only...
    • How to Make a Tsunami - Duration: 66 seconds.

      • 5 years ago
      • 10,662 views
      This cartoon shows schematically how a subduction earthquake generates a tsunami. The green material is the lithosphere (which is brittle) and the purple-red material is the asthenosphere (which, w...
    • Perspective: a graphical comparison of earthquake energy release - Duration: 113 seconds.

      • 1 year ago
      • 10,988 views
      Tsunami warning center scientists usually measure an earthquake's "size" with the moment magnitude scale rather than the older but more famous Richter magnitude scale. The moment magnitude scale is...
    • Tsunami Animation: Three Tsunamis From Chile - Duration: 97 seconds.

      • 4 years ago
      • 45,967 views
      This side-by-side comparison of three tsunamis generated within the same region highlights two important characteristics of tsunami behavior.

      First, the height of the tsunami waves (as shown by co...
    • TSUNAMI WARNING! - Duration: 6 minutes, 3 seconds.

      • 5 years ago
      • 18,814 views
      Since an earthquake's fastest wave, its primary or P-wave, travels about 50 times faster than the fastest tsunami waves, a tsunami warning center will issue its initial tsunami warning based on sei...
    • Thrust vs. Strike-Slip Mechanisms in PTWC's Tsunami Forecast Model - Duration: 81 seconds.

      • 5 years ago
      • 3,485 views
      On April 11, 2012, PTWC scientists responded to a pair of very unusual earthquakes, 8.6 and 8.2 magnitude strike-slip events, the largest of this type ever recorded. They did not know the quakes we...
    This item has been hidden
  • Earthquake Animations Play all

    • How to Make a Tsunami - Duration: 66 seconds.

      • 5 years ago
      • 10,662 views
      This cartoon shows schematically how a subduction earthquake generates a tsunami. The green material is the lithosphere (which is brittle) and the purple-red material is the asthenosphere (which, w...
    • Perspective: a graphical comparison of earthquake energy release - Duration: 113 seconds.

      • 1 year ago
      • 10,988 views
      Tsunami warning center scientists usually measure an earthquake's "size" with the moment magnitude scale rather than the older but more famous Richter magnitude scale. The moment magnitude scale is...
    • Earthquakes of the First 15 Years of the 21st Century - Duration: 3 minutes, 50 seconds.

      • 2 years ago
      • 417,147 views
      This animation shows every recorded earthquake in sequence as they occurred from January 1, 2001, through December 31, 2015, at a rate of 30 days per second. The earthquake hypocenters first appea...
    • The 27 February 2010 Maule, Chile Earthquake and its Aftershocks - Duration: 57 seconds.

      • 5 years ago
      • 26,029 views
      This animation shows the 8.8 magnitude earthquake that struck Maule, Chile on 27 February 2010 and the first six months of its aftershocks.

      These almost nine-months' worth of earthquake data will ...
    • The Great Tōhoku-Oki Earthquake: Its Foreshock, Mainshock, and Aftershocks - Duration: 77 seconds.

      • 5 years ago
      • 5,523 views
      This animation shows the 9.0 magnitude earthquake that struck off the coast of Japan's Tōhoku-Oki region on 11 March 2011 and the first six months of its aftershocks.

      For animations of the resulti...
    • Context: a graphical comparison of earthquake energy release in Hawaiʻi - Duration: 70 seconds.

      • 6 months ago
      • 1,225 views
      On May 4, 2018, the largest earthquake in 43 years struck Hawaiʻi with a moment magnitude of 6.9 in the Kalapana region of the Island of Hawaiʻi (the “Big Island”). This animation puts that earthqu...
    • The First 100 Days of New Activity on Kīlauea Volcano - Duration: 2 minutes, 40 seconds.

      • 3 months ago
      • 6,179 views
      The NWS’s Pacific Tsunami Warning Center (PTWC) mitigates tsunami hazards in Hawai‘i produced by large, distant earthquakes throughout the Pacific Ocean, but PTWC also issues warnings for tsunamis ...
    • Earthquake Animation: Kīlauea Caldera - 1 April to 31 August 2018 - Duration: 2 minutes, 54 seconds.

      • 2 months ago
      • 1,884 views
      The NWS’s Pacific Tsunami Warning Center (PTWC) mitigates tsunami hazards in Hawai‘i produced by large, distant earthquakes throughout the Pacific Ocean, but PTWC also issues warnings for tsunamis ...
    • Earthquakes of the 20th Century - Duration: 2 minutes, 37 seconds.

      • 4 days ago
      • 3,233 views
      This animation shows every recorded earthquake in sequence as they occurred from January 1, 1901, through December 31, 2000, at a rate of 1 year per second. The earthquake hypocenters first appear ...
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  • RIFT Tsunami Forecast Model Animations (Mercator) Play all

    Tsunami forecast animations created with PTWC's real-time forecast model, RIFT (Wang et al., 2012) and shown in Mercator map projection
    • Tsunami Forecast Model Animation: Cascadia 1700 - Duration: 81 seconds.

      • 2 years ago
      • 438,565 views
      Just before midnight on January 27, 1700 a tsunami struck the coasts of Japan without warning since no one in Japan felt the earthquake that must have caused it. Nearly 300 years later scientists a...
    • Tsunami Forecast Model Animation: Lisbon 1755 - Duration: 87 seconds.

      • 2 years ago
      • 42,979 views
      On the morning of November 1, 1755, a great earthquake shook Portugal's capital city of Lisbon as worshipers filled churches and cathedrals for the All Saints' Day Mass. In seconds it left the city...
    • Tsunami Forecast Model Animation: Aleutian Islands 1946 - Duration: 110 seconds.

      • 2 years ago
      • 9,108 views
      On April 1, 1946 at 4:28 am (12:28 UTC), an 8.6 moment magnitude earthquake struck off the coast of Unimak Island in Alaska’s Aleutian Islands, generating a tsunami that caused the greatest damage ...
    • Tsunami Forecast Model Animation: Aleutian Islands 1957 - Duration: 110 seconds.

      • 1 year ago
      • 4,287 views
      At 4:22 am on Saturday, March 9, 1957 (9 March, 14:22 Z UTC) the second great earthquake in 11 years struck Alaska’s Aleutian Islands. This earthquake had the same magnitude of the earlier earthqua...
    • Tsunami Forecast Model Animation: Chile 1960 - Duration: 110 seconds.

      • 2 years ago
      • 60,075 views
      On May 22, 1960, at 3:11 pm (19:11 UTC) the largest earthquake ever recorded by instruments struck southern Chile with a magnitude we now know to be at least 9.5. This earthquake generated a tsunam...
    • Tsunami Forecast Model Animation: Alaska 1964 - Duration: 87 seconds.

      • 2 years ago
      • 14,869 views
      At 5:36 pm on Friday, March 27, 1964 (28 March, 03:36Z UTC) the largest earthquake ever measured in North America, and the second-largest recorded anywhere, struck 40 miles west of Valdez, Alaska i...
    • Tsunami Animation: Hawaii 1975 - Duration: 58 seconds.

      • 2 weeks ago
      • 2,550 views
      Not all tsunamis in the Hawaiian Islands come from overseas. On the early morning of November 29, 1975, a 7.7 magnitude* earthquake struck the southeast coast of the Big Island of Hawaii and genera...
    • Tsunami Forecast Model Animation: Sumatra 2004 - Duration: 86 seconds.

      • 1 year ago
      • 44,798 views
      The magnitude 9.1 Great Sumatra-Andaman Earthquake of December 26, 2004, spawned the deadliest tsunami in history, killing more than 230,000 people in 14 countries around the Indian Ocean. More th...
    • Tsunami Forecast Model Animation: Samoa 2009 - Duration: 87 seconds.

      • 2 years ago
      • 5,999 views
      At 6:48 on the morning of September 29, 2009 (17:48 UTC), an 8.1 moment magnitude earthquake struck near the Samoan Islands in the southwest Pacific Ocean. The Pacific Tsunami Warning Center (PTWC)...
    • Tsunami Forecast Model Animation: Chile 2010 - Duration: 99 seconds.

      • 2 years ago
      • 91,152 views
      At 3:34 on the morning of February 27, 2010 (06:34 UTC), an 8.8 moment magnitude earthquake struck near the coastline of central Chile. The Pacific Tsunami Warning Center (PTWC) quickly determined ...
    • Tsunami Forecast Model Animation: Japan 2011 - Duration: 110 seconds.

      • 2 years ago
      • 131,031 views
      At 14:46 on the afternoon of 11 March 2011 (05:46 UTC), a 9.0 moment magnitude earthquake struck near the coastline of Honshu, Japan. The Pacific Tsunami Warning Center (PTWC) quickly determined th...
    • Thrust vs. Strike-Slip Mechanisms in PTWC's Tsunami Forecast Model - Duration: 81 seconds.

      • 5 years ago
      • 3,485 views
      On April 11, 2012, PTWC scientists responded to a pair of very unusual earthquakes, 8.6 and 8.2 magnitude strike-slip events, the largest of this type ever recorded. They did not know the quakes we...
    This item has been hidden
  • RIFT Tsunami Forecast Model Animations (virtual globe) Play all

    Tsunami forecast animations created with PTWC's real-time forecast model, RIFT (Wang et al., 2012) and shown on a virtual globe
    • Tsunami Animation: Unimak Island, Aleutian Islands, 1946 (rotating globe) - Duration: 109 seconds.

      • 4 years ago
      • 7,320 views
      The Eastern Aleutian earthquake of April 1, 1946 spawned Hawaii's most damaging tsunami. The tsunami flooded all coastlines of all islands and resulted in 159 deaths. The tsunami arrived at about 6...
    • Tsunami Animation: Prince William Sound, Alaska, 1964 (virtual globe) - Duration: 89 seconds.

      • 4 years ago
      • 9,009 views
      One of the largest earthquakes ever recorded by instruments (and the largest ever in the United States) struck south-central Alaska on March 27, 1964 (local time). This 9.2 magnitude earthquake gen...
    • Tsunami Animation: Valdivia, Chile, 1960 (rotating globe) - Duration: 109 seconds.

      • 3 years ago
      • 80,898 views
      The largest earthquake ever recorded by instruments struck southern Chile on May 22, 1960. This 9.5 magnitude earthquake generated a tsunami that crossed the Pacific Ocean, killing as many as 2000 ...
    • Tsunami Animation: Sumatra, 2004 - Duration: 106 seconds.

      • 4 years ago
      • 169,602 views
      The magnitude 9.1 Great Sumatra-Andaman Earthquake of December 26, 2004, spawned the deadliest tsunami in history, killing more than 230,000 people in 14 countries around the Indian Ocean. More th...
    • Tsunami Animation: Maule, Chile 2010 (rotating globe) - Duration: 2 minutes, 25 seconds.

      • 4 years ago
      • 20,819 views
      This animation shows how PTWC's real-time tsunami forecast model, RIFT, predicts the behavior of the tsunami following the 8.8 magnitude earthquake in Maule, Chile on 27 February 2010. The animatio...
    • Tsunami Animation: Tohoku, Japan 2011 (rotating globe) - Duration: 2 minutes, 44 seconds.

      • 4 years ago
      • 26,489 views
      This animation shows how PTWC's real-time tsunami forecast model, RIFT, predicts the behavior of the tsunami following the 9.0 magnitude earthquake offshore of the Tōhoku-Oki region, Japan, on 11 M...
    • TSUNAMI WARNING! - Duration: 6 minutes, 3 seconds.

      • 5 years ago
      • 18,814 views
      Since an earthquake's fastest wave, its primary or P-wave, travels about 50 times faster than the fastest tsunami waves, a tsunami warning center will issue its initial tsunami warning based on sei...
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