Download Rapid Changes

TEKS 3.7B investigate rapid changes in Earth’s surface such as volcanic
eruptions, earthquakes, and landslides
Rapid Changes in Earth’s Surface
Constant Changes
Earth’s surface is constantly changing. Wind, water, and ice break down
large rocks and move sediments on the surface. It usually takes years for
weathering, erosion, and deposition to cause noticeable changes. Some
events, though, change Earth’s surface much more quickly. These include
volcanic eruptions, earthquakes, and landslides. These events have the
ability to cause large changes in a much shorter period of time.
Earthquakes
The surface of the Earth is called the crust. The Earth’s crust is divided into
sections called plates. These plates fit
together like the pieces of a puzzle.
Earth’s plates are constantly in motion.
As one plate moves, it causes the other
nearby ‘puzzle pieces’ to also move.
Sometimes, these plates get caught on
one another and pressure builds up.
An earthquake occurs when this
pressure is suddenly released. An
earthquake is a shaking of the ground. Most earthquakes are too small to
be felt, but if an earthquake is large enough, it can
cause a great deal of damage to buildings and roads.
A major earthquake can cause the land to move
several meters.
Tsunamis
An earthquake in the ocean floor can cause a
tsunami. A tsunami is a fast-moving wave that can
bring a large volume of water rushing on shore. The
waves of a tsunami carry the energy from the earthquake and can cause
extreme damage to coastlines.
Volcanoes
Underneath Earth’s surface, rock can be so hot that it
melts. This molten rock is called magma. A volcano
is a vent or opening in Earth’s surface through which
magma and hot gases can erupt. Magma is called
lava when it reaches the surface of the Earth. Most
volcanoes occur near the edges of plates where the
plates are pulling away from one another. Volcanoes
can change Earth’s surface in several ways. Flowing
lava destroys trees and other plant life. Animals that
can’t escape are also burned. After a major volcano, surviving animals often
are left with no food and most move to a new location. Volcanic eruptions
lay down thick, dense layers of rock that can form new islands.
Landslides
If you have ever taken a trip through a mountainous area, you may have
seen road signs warning of falling rocks. Weathering causes rocks to break
free, and gravity pulls them tumbling down the mountain side. Sometimes,
the same thing happens with a large area of rock or soil at once. A
landslide is the fast movement of soil and rocks down a slope. Landslides
can be very dangerous.
Landslides occur in the ocean,
along the coast, and on shore.
Many factors determine how stable
a slope is. Some landslides occur
naturally. They are set off by heavy
rains, floods, earthquakes, or
volcanoes. Excessive human
development and construction
along hillsides can also cause
landslides.
Rapid Changes
Changes to Earth can happen suddenly or over long periods of time.
Earthquakes, volcanoes, tsunamis and landslides are naturally occurring
events that can rapidly change Earth’s surface.