Sixty percent of all active volcanoes occur at the boundaries between tectonic plates. Most volcanoes are found along a belt, called the “Ring of Fire” that encircles the Pacific Ocean. Some volcanoes, like those that form the Hawaiian Islands, occur in the interior of plates at areas called “hot spots.”

Most volcanoes form at the boundaries of Earth’s tectonic plates. At a divergent boundary, tectonic plates move apart from one another. They never really separate because magma continuously moves up from the mantle into this boundary, building new plate material on both sides of the plate boundary.

The San Andreas Fault is a transform boundary. Subduction of the Juan de Fuca plate beneath the North American plate creates the Cascade volcanoes. Subduction of the Pacific plate beneath the North American plate in the north creates the Aleutian Islands volcanoes.

If two tectonic plates collide, they form a convergent plate boundary. The new magma (molten rock) rises and may erupt violently to form volcanoes, often building arcs of islands along the convergent boundary. When two plates are moving away from each other, we call this a divergent plate boundary.

Different parts of Earth’s surface receive different amounts of sunlight. The sun’s rays strike Earth’s surface most directly at the equator. This focuses the rays on a small area. Because the rays hit more directly, the area is heated more.

If the Earth system is changed either through natural phenomena — such as volcanoes — or man’s activities and an imbalance in the Earth’s energy budget occurs, the Earth’s temperature will eventually increase or decrease in order to restore an energy balance.

the sun

What would happen if most of Earth’s surface suddenly became covered with ice? -Earth would cool down because it would reflect more solar radiation. -Earth would cool down because it would absorb more solar radiation. These gas molecules then re-release some of this heat back toward Earth’s surface, warming it.