Naturally Speaking

The Dynamic Planet, part two

Community Contributed

By G.T. Larson

If you take a stick and very slowly bend it until it breaks, you will have a very simple example of what happened on March 11 off the northeast coast of Japan.

The Pacific Plate, which the Hawaiian Islands reside upon, is slowly moving toward the western arm of the North American Plate at approximately three and three quarter inches per year. The Pacific Plate is pushing under, or subducting under the North American Plate, that creates the Japan Trench off the east coast of Japan. This subduction zone is the reason that the islands of Japan exist. The many volcanoes that originally created the landmass of Japan and continue to affect their daily lives and the frequent earthquakes that disrupt the modern Japan of today are, for the most part, all a result of the subducting of the Pacific Plate with the North American Plate.

This movement is not smooth and gradual. Resistance between the two plates can cause pressure to build up until there is a violent readjustment. In the March 11earthquake, tremendous energy had built up and was released in what is called a thrust fault – a 300-mile-long fault plane, or section, of the North American Plate thrust up 100-130 feet from its former position. This upward jolt of hundreds of square miles of seafloor also moved hundreds of cubic miles of ocean water – which radiated a wave train of tremendous seismic energy out in all directions, causing the tsunami.

The epicenter, or point of origin, of the March 11 earthquake was about 80 miles off the northeast coast of Japan. Traveling at 500 miles per hour, the first waves slammed the Sendai coast within minutes and tsunami warnings were issued for the Pacific basin. As the tsunami train moved out into the Pacific, the Tsunami Warning Center on Oahu began to closely monitor a series of buoys and observation stations for data on the possible size of the approaching event.

In our third part we will look at the local effects of the earthquake generated tsunami on Hawaii and in particular, Molokai.

We live on a dynamic planet. It is ever changing and reconfiguring. May we take a lesson from nature and learn to adjust and change as needed, but stand firm for principle and righteousness when called for. Aloha Ke Akua.