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"Silent Earthquake" in Hawaii
Posted February 2002

The Hawaiian Islands were created by a series of volcanoes on the ocean floor. Over millions of years, the volcanoes erupted underwater and the lava that poured out eventually solidified into hardened rock. After many years of eruptions, the Hawaiian islands were formed.

There are 137 islands in the Hawaiian island chain, but only eight main islands in the state of Hawaii. The largest island of Hawaii is the youngest island and the only one that has active volcanoes. The Kilauea volcano is huge a tourist attraction on this island. Vacationers charter helicopter and airplane flights to fly them over the open Kilauea crater where they can catch a glimpse of Kilauea's lava lake.

The Kilauea volcano began erupting in 1983 and has been erupting constantly since. A massive area of the south side of Hawaii is covered with huge lava flows from Kilauea that literally poured over roads, houses, and villages. In fact, some tourists will hike across the massive lava flows to watch the red-hot lava pour into the Pacific Ocean.

This can be a dangerous practice for tourists because the new rock is unstable and can slip or break open. In fact, the rock surrounding Kilauea recently broke and shifted 3.5 inches towards the Pacific Ocean. The huge chunk of rock is 12 miles wide, 6 miles long, and 5 miles deep.

This eruption of Kilauea is being called a "silent earthquake" by geologists because there was a movement of Earth, but there was no actual rumbling or shaking of the ground. This movement was detected by Global Positioning System (GPS) satellites in November 2000. It was reported over a year later in the February 28, 2002 issue of Nature.

Scientists are warning that this movement could be the first indication of a larger disaster waiting to happen if a chunk of the island were to fall into the Pacific Ocean. While the lava-covered sections of Hawaii are not populated, if a chunk of the island fell into the Pacific Ocean, this could generate a huge wave in the ocean known as a tsunami. Tsunamis are huge waves that can pile up to over 100 feet when they hit the shore. In fact, the city of Hilo on Hawaii has been hit with several devastating tsunamis in the past.

If a chunk falls off the Kilauea volcano, it could generate a huge tsunami that could spread throughout the Pacific and eventually hit coastlines as far away as Australia, Ecuador, Chile, or California.

Activity
Use the Internet to research tsunamis and how they form. In your Science Journal, write a safety guide for people who live in areas prone to tsunamis.


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