A great deal is known about the "where" of earthquake prediction but currently there is no reliable method of predicting the "when" of earthquakes.

Scientists can make reasonably accurate long-term predictions of the location of earthquakes. It is known that 80% of the world's major earthquakes occur on long fault zones around the margin of the Pacific Ocean. This area is known as the Ring of Fire due to frequent geological activity such as volcanoes, earthquakes, and other events of that nature. This is an active geological zone because the Atlantic Ocean is growing a few inches wider each year and the Pacific Ocean is shrinking as ocean floor is being pushed beneath Pacific Rim continents.

Due to the disasterous consequences of earthquakes, scientists are persistent in their efforts to come up with a successful prediction method. One successful prediction was for the Haicheng, China earthquake of 1975, which struck with a force of 7.3 on the Richter scale. In the months before the quake there were reports of changes in land elevation, ground water levels, and animal behavior. A low level warning was issued. Then an increase in foreshock activity led to an evacuation warning. It was believed thousands of lives were saved because of this action. Unfortunately, such signals did provide warning for the 1976 Tangshan earthquake, magnitude 7.6, which claimed 250,000 lives.

While it is difficult to predict when a specific earthquake will strike, the average times between earthquakes in a given zone can be determined. In south Hawaii, the average time between magnitude 7 or larger earthquakes is 29-44 years. For a magnitude 8 or larger, the average time is 120-190 years. In the Kona and Hualalai areas of west Hawaii, the average time is 3-10 years for magnitude 5.5 earthquakes and 265-300 years for magnitude 7 quakes.

Seismic hazard mapping assigns a zone level to an area, based upon the predicted frequency of earthquake events. The oldest inhabited islands of Hawaii, Ni'ihau and Kauai, are given the lowest rating of zone one. The Big Island of Hawaii, where the Kilauea volcano is erupting, is assigned the highest rating of zone four.

 

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