In this topic, you will learn about how Earth's land changes suddenly.

There are several events that speed up the weathering and erosion of Earth's land. One of these events is a hurricane. A hurricane is a violent storm with strong winds and heavy rains. Hurricanes are the largest and most powerful of storms. They begin over oceans. Hurricane winds move in a circular pattern at speeds of 75 miles per hour or more. Most hurricanes die out far from land. Hurricanes that move toward land act like giant bulldozers. Strong winds and giant waves damage or destroy almost everything in their path. Flooding occurs. Trees are uprooted. Lives are often lost.

Another event that causes sudden changes to Earth's surface is an earthquake. An earthquake is a sudden movement in the rocks that make up Earth's crust. Earthquakes are caused by forces deep within Earth. The forces cause rocks to break. The breaking rock makes the ground shake. Strong earthquakes cause landslides, great destruction, and loss of lives. People may be left homeless when houses are destroyed. Cities may lose electricity and water as power and water lines break. Food supplies may run low if transportation is interrupted. Fires may also break out.

Sudden changes to Earth's surface are also caused by volcanoes. A volcano is an opening in the surface of Earth. Melted rock, gases, pieces of rock, and dust are forced out of this opening. Melted rock that flows out onto the ground is called lava.