Lurking under the Pacific Ocean are giant pieces of Earth's crust moving in directions that are the opposite of each other. These enormous, continent-carrying plates of earth meet in two ways: They squeeze by each other side to side, or one can push under the other. Subduction zones form as these continental shelves fight to move; the heavier land mass pushes under the lighter, forming mountains and volcanoes as the crust rips and the hot molten rock from below flows upward.
From the Southern tip of South America, around the coast of North America, through the Bering Straits, across Japan and ending partway through New Zealand sit 452 volcanoes and the wrestling ground for a myriad of these huge, floating tectonic plates. This giant, horseshoe-shaped area around the Pacific Ocean is the Ring of Fire.
The Ring of Fire is the most seismically active area in the world. Mount St. Helens, on the Pacific Coast of North America, erupted violently in the 1980s and continues to puff and rumble as geologists watch the growing caldera. The Pacific plate in this region is pushing the North American plate upward, which is how cone volcanoes form. The subduction zone makes the rocky coastal ranges and shakes the land as well.
Earthquakes caused by the restless continental shelves tear the Earth's crust below, and the tears allow molten rock and lava to flow into the center of the rock. The earth underneath continues to push up and the lava chamber, or caldera, fills with more lava. Trapped inside the rock, pressure builds until the heat must escape and the caldera explodes, taking mountain, trees and man with it.
Along subduction zones, as the Earth's tectonic plates fight for room, massive earthquakes shake the ocean floor and nearby land. The size of these quakes reaches 9.3 on the Richter scale at times and sends tsunamis hurtling through the ocean at speeds of up to 500 mph. Only 6 " to 12" of a tsunami may show on the surface of the ocean, while under the deceptive surface a series of waves, each up to 600 miles in length, transports unimaginable volumes of displaced water toward unsuspecting shores.
Japan sits precariously atop the Pacific and the Eurasian plates, which have pushed and buckled more than any others in the Ring of Fire. The Pacific plate is the largest and almost the entire Pacific Ocean rides atop its mass. Because of its enormous mass, the plate moves as much as 4 inches a year with little drag to slow it down. Each time the plate pushes under the Eurasian plate, the area above grows taller, as the land snaps and heaves at the movement. Tsunamis from these events have devastated the shores of Japan for centuries.
Mt. Fuji also lives near Japan and is a direct result of the tectonic activity going on under the ocean. The stratovolcano last erupted in 1707 and 1708; however, the mountain rumbles and a lava chamber exists inside. The volcano reaches over 12,000 feet into the sky and is visible 62 miles away in Tokyo.
Massive tsunamis devastated Indonesia in 2004 after a 9.1 earthquake in the Indian Ocean. The tsunami shocked geologists and oceanographers with its deadly force and worldwide destruction. The disaster killed more than 150,000 people from Indonesia to Africa, 3000 miles away. The waves traveled that distance and hit Africa's coastline seven hours after the initial earthquake.
The Ring of Fire is a turbulent, restless place on Earth. No one can predict when the next volcano will erupt, throwing fire and ash into the atmosphere and darkening the sky over much of the world. Nor can anyone predict the next megaquake that will send an onslaught of ruthless water speeding toward land to destroy the masses. The children of the Earth wait arrogantly as the Ring of Fire readies for its next attack.