Earth Science - Other

Geologic Forces that both Create and Destroy



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The destructive Tsunami that hit Japan in March of 2011 was the result of a powerful point nine earthquake. It is both the magnitude of an earthquake and the geology of land and sea that affect a tsunami's intensity. The even more destructive Indian Ocean tsunami of December 2004 , for example, was also caused by a Richter scale point nine earthquake.

That horrific event led to new measures for evacuation, preparedness and prediction. Other factors affecting fatalities include such things as population density and infrastructure in place to cope with seismic events. Over 300,000 people lost their lives because so very many lived in thriving coastal areas in 2004. Across the entire Pacific new policies were put into place which will save future lives.

A tsunami will more frequently strike within the area known as the Pacific ring of fire. This is the  geologically active area of the entire Pacific Ocean, ringed by Asia, Australia and North and South American land masses.  Underwater slipping along the fault line generates the earthquake and subsequent waves that can travel across the entire ocean, usually in less than 22 hours.  Not all tsunami events are from earthquakes. More rarely, a submarine or near-shore volcano or the even less-frequent meteor strike can grow the immense waves. Volcanic tsunamis can perpetuate waves of such height and power that they overwhelm entire regions.

In recorded history, the waves from the Krakatau event in 1883 were documented to be up to 125 feet above sea level. Many coastal villages were wiped from the map and untold thousands died.

Hilo, Hawaii, is struck by an occasional tsunami due to its central Pacific location.  Yet, only a few Hawaiian tsunamis have been so destructive. An earthquake off the Aleutian Islands generated one in 1945. Another in 1960 found a landscape that was a bit more prepared. Locating less housing and business districts close to shoreline saves many lives and more property, and having a far more sophisticated prediction system helps even more.

The Pacific Tsunami Warning Center, The West Coast and Alaska warning centers, the Deep Ocean Assessment and Reporting of Tsunamis, or DART, and even NASA with Global Differential Global Positioning Satellite, GDGPSs, all work together to provide as much data and warning information as possible before a major seismic event can reach a vulnerable shore.

It is not unexpected that any major change that builds or releases major weight pressure or affects geologic stress and strain should have such effects. Despite all the technology in place to detect a tsunami before it strikes, there is a growing threat of more destruction from tsunamis due to climate change. Melting ice means a change in how much more Earth is exposed; leaking methane beneath the ocean and more vulnerable coastlines due to lost outlying natural barriers are all factors.

In recent years, the devastating effects of tsunamis do serve as reminders of just how powerful geologic creation can be. Better disaster preparedness and response help provide hope and a moving legacy to the hundreds of thousands of people worldwide who are killed or injured, and many thousands more who lose homes and businesses.

All creative forces are forever linked to those more often thought of as destructive. For all the long term beauty and serenity of the sea and shore, there will always be those few moments of terror that should never be forgotten.The ever-evolving creation of geologic forces cannot be taken for granted. Humility before the forces of nature requires both respect and caution.  

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ARTICLE SOURCES AND CITATIONS
  • InfoBoxCallToAction ActionArrowhttp://education.nationalgeographic.com/education/encyclopedia/ring-fire/?ar_a=1
  • InfoBoxCallToAction ActionArrowhttp://www.geology.sdsu.edu/how_volcanoes_work/Krakatau.html