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Tsunamis

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A tsunami is a series of extremely long waves caused by a large and sudden displacement of the ocean, usually the result of an earthquake below or near the ocean floor. This force creates waves that radiate outward in all directions away from their source, sometimes crossing entire ocean basins. Unlike wind-driven waves, which only travel through the topmost layer of the ocean, tsunamis move through the entire water column, from the ocean floor to the ocean surface.  How devastating can a tsunami be? On the morning of March 28, 1964, without warning, the largest recorded earthquake in U.S. history struck Alaska’s Prince William Sound. The 9.2 magnitude earthquake and subsequent tsunamis ravaged coastal communities and killed more than 139 people. More information on this event can be found here.
 

NOAA’s Role:

  • To detect and observe tsunamis as they move across the ocean, NOAA depends on networks of seismic and sea-level observation systems. These networks are owned and operated by several domestic and international organizations, including NOAA. NOAA’s success in fulfilling this important mission relies on the ability to quickly detect a tsunami, which is accomplished through networks of advanced observation systems.

  • Key components of this observation system are Deep-ocean Assessment and Reporting of Tsunamis (DART©) buoys. These detection buoys were developed by NOAA, and continue to be updated as new R&D improves upon the technology.

  • NOAA maintains one of two global historical tsunami databases. – Gusiakov, V.K., P.K. Dunbar, and N. Arcos, Twenty-Five Years (1992-2016) of Global Tsunamis: Statistical and Analytical Overview. PURE AND APPLIED GEOPHYSICS, 2019. 176(7): p. 2795-2807. https://doi.org/10.1007/s00024-019-02113-7

  • From initial funding in 1996 to 2011, a $10 million research and development effort has led to the invention of three generations of real-time deep-ocean tsunameters that have provided deep-ocean data from over 40 tsunamis. These tsunami data have been used to accelerate the verification and validation of tsunami forecast models that are now capable of forecasting tsunami time series and flooding at coastal communities with 80% accuracy. Accurate tsunami forecasts have improved public response to tsunamis by avoiding false alarms (i.e., 2009 Samoan tsunami) and advising appropriate evacuations (i.e., 2011 Japan tsunami). – Bernard, E. N., & Meinig, C. (2011). History and future of deep-ocean tsunami measurements, Waikoloa, HI, USA, 2011, pp. 1-7. https://ieeexplore.ieee.org/document/6106894

Why it Matters:

Value of Tsunami Observation Systems

DART©, tsunami detection buoys developed by NOAA, provide significant value in avoided tsunami damages, well above their cost:

  • The benefits from DART© tsunami detection buoys are between $2.8 million and $90 million per year for the entire region and between $1.4 million and $45 million per year for independent countries over an expected 15-year designed life. The lower bounds assume 7% of damages are avoided and tsunami occurrences of 1/500 years while the upper bounds assume 45% of damages are avoided and tsunami occurrences of 1/100 years. – Jin, D. and J. Lin, Managing tsunamis through early warning systems: A multidisciplinary approach. Ocean & Coastal Management, 2011. 54(2): p. 189-199. https://doi.org/10.1016/j.ocecoaman.2010.10.025
Preparing for the impact of a tsunami can lead to costly evacuations:
  • For the State of California, the cost of evacuations in potentially inundated areas was estimated to be $2.8 billion (2010$).This finding was based on a hypothetical tsunami created by a 9.1 magnitude earthquake offshore the Alaskan Peninsula on the 27th of March 2014 in the Southern California region.  – Rose, A., Sue Wing, I., Wei, D., & Wein, A. (2016). Economic Impacts of a California Tsunami. Natural Hazards Review, 17(2), 04016002. https://doi.org/10.1061/(ASCE)NH.1527-6996.0000212

  • The economic benefit to Hawaii from more accurate tsunami forecasts has been the avoidance of at least three unnecessary evacuations saving an estimated $200 million (2011$). – Bernard, E. N., & Meinig, C. (2011). History and future of deep-ocean tsunami measurements, Waikoloa, HI, USA, 2011, pp. 1-7. https://ieeexplore.ieee.org/document/6106894

Historic Impact

Tsunamis have led to a significant number of fatalities since the early 1990s:

  • During the period from 1992 – 2015 there were 290 global tsunami events. Among these events, 32 tsunamis resulted in human fatalities and 63 tsunamis resulted in physical damages. Over the entire 25-year period examined there were a total of 251,869 fatalities due to tsunamis. – Gusiakov, V.K., P.K. Dunbar, and N. Arcos, Twenty-Five Years (1992-2016) of Global Tsunamis: Statistical and Analytical Overview. PURE AND APPLIED GEOPHYSICS, 2019. 176(7): p. 2795-2807. https://doi.org/10.1007/s00024-019-02113-7

Impacts to Property

Tsunamis can impact property through flooding and storm surge:

    • For the State of California, the value of property damage along the coast was estimated to be $0.9 billion (2010$). This finding was based on a hypothetical tsunami created by a 9.1 magnitude earthquake offshore the Alaskan Peninsula on the 27th of March 2014 in the Southern California region. – Rose, A., Sue Wing, I., Wei, D., & Wein, A. (2016). Economic Impacts of a California Tsunami. Natural Hazards Review, 17(2), 04016002. https://doi.org/10.1061/(ASCE)NH.1527-6996.0000212
    • For the State of California, property damages centered around the inundation of the Ports of Los Angeles and Long Beach would amount to $2.6 billion (2010$). This finding was based on a hypothetical tsunami created by a 9.1 magnitude earthquake offshore the Alaskan Peninsula on the 27th of March 2014 in the Southern California region.  – Ross et al (2013). The SAFRR tsunami scenario: improving resilience for California [Report](2013-3081). (Fact Sheet, Issue. U. S. Geological Survey. https://pubs.usgs.gov/publication/fs20133081
    • In simulated scenarios of five tsunamis triggered by 8.7-9.3 magnitude earthquakes in the Cascadia subduction zone, the direct property damages to buildings located in Seaside, Oregon was estimated to range (depending on the percentage of buildings inundated) from $2 million to $1.2 billion (2011$). – Wiebe, D. M., & Cox, D. T. (2014). Application of fragility curves to estimate building damage and economic loss at a community scale: a case study of Seaside, Oregon. Natural Hazards, 71(3), 2043-2061. https://doi.org/10.1007/s11069-013-0995-1 

 

Impacts to Labor

Tsunamis may impact employment levels long after they occur:

    • The city of Hilo, the economic center and the largest settlement in the county of Hawaii, was affected more severely by the tsunami that occurred on the 23rd of May 1960 than other areas of the Islands, with the city suffering 9% and 33% lower levels of population and employment in the 15 years following the event.  – Lynham, J., Noy, I., & Page, J. (2017). The 1960 Tsunami in Hawaii: Long-Term Consequences of a Coastal Disaster. World Development, 94, 106-118. https://doi.org/https://doi.org/10.1016/j.worlddev.2016.12.043 

 

Impacts to Commerce and Trade

Tsunamis may significantly impact trade through direct damages to ports, cargo disruptions, and lost productivity:

  • For the State of California, the value of lost productivity (i.e., reduction in GDP) in industries directly impacted by port cargo disruptions at the Port of Los Angeles and the Port of Long Beach was estimated to be $2.2 billion (2010$).This finding was based on a hypothetical tsunami created by a 9.1 magnitude earthquake offshore the Alaskan Peninsula on the 27th of March 2014 in the Southern California region. – Rose, A., Sue Wing, I., Wei, D., & Wein, A. (2016). Economic Impacts of a California Tsunami. Natural Hazards Review, 17(2), 04016002. https://doi.org/10.1061/(ASCE)NH.1527-6996.0000212  
  • Economic losses, centered around the inundation of the Ports of Los Angeles and Long Beach, include $100 million in damages to cargo, $0.5 – $1.2 billion in losses associated with trade disruptions (accounting for business resilience strategies such as using existing inventories and working extra shifts), $700 million in marina and small craft damage, and $82 million (2010$) in highway and railroad repairs. These findings were based on a hypothetical tsunami created by a 9.1 magnitude earthquake offshore the Alaskan Peninsula on the 27th of March 2014 in the Southern California region.  – Ross et al (2013). The SAFRR tsunami scenario: improving resilience for California [Report](2013-3081). (Fact Sheet, Issue. U. S. Geological Survey. https://pubs.usgs.gov/publication/fs20133081
  • Based on impacts to economic productivity due to inundation, “the distributed losses related to a major tsunami in Southern California could exceed $7 billion, and be as high as $42 billion (2015$), depending largely on the degree to which the infrastructure at the Port of Los Angeles and the Port of Long Beach is affected.”  – Borrero, J., Cho, S. B., Moore, J. E., Synoloakis, C., & Richardson, H. W. (2015). The Regional Economic Impacts of a Tsunami Wave. In REGIONAL ECONOMIC IMPACTS OF TERRORIST ATTACKS, NATURAL DISASTERS AND METROPOLITAN POLICIES (pp. 129-144). https://doi.org/10.1007/978-3-319-14322-4
  • A simulated tsunami event caused by a 9.2 magnitude earthquake in Clatsop County, Oregon, would lead to $554.71 million (2018$) in productivity losses. The largest productivity losses would be to the finance and real estate sectors with estimated losses of $111.7 million. This is closely followed by losses to the tourism sector with an estimated loss of $111.1 million. – Chen, Y. G., Park, H., Chen, Y., Corcoran, P., Cox, D., Reimer, J. J., & Weber, B. (2018). Integrated Engineering-Economic Model for the Assessment of Regional Economic Vulnerability to Tsunamis. Natural Hazards Review, 19(4), Article 04018018. https://doi.org/10.1061/(ASCE)NH.1527-6996.0000307