Destructive Processes Weathering is the breakdown of rocks by the action of rain, cold, snow, etc. at or near Earth’s surface. Mechanical weathering breaks rock into smaller pieces without changing it chemically. Soil is the material in which most plants grow. Erosion is the movement of weathered rock from place to place. Water, wind, glaciers, and ocean waves are agents of erosion.

Destructive process: Erosion Desert pavement is a surface of only bare ground and large stones. A groin a structure built at right angles to the beach. A seawall is a structure built parallel to the shore. Contour plowing is a method in which farmers plow across the sides of hills instead of down their slopes. Terracing is a method in which farmers plant crops on terraces built on hillsides. Storm drain management is a system of drains that prevents flooding during heavy rainstorms.

Destructive processes: Glaciers Sea stacks are pillars of stone in the sea that form from headlands. Headland is a point of land that juts out into the ocean. To form a Sea arch, waves first carve away softer rock in the headland. Gravity is a force that pulls all objects toward each other. The sudden movement of rocks and soil down side of a hill is called a landslide.

Destructive Process: Volcanoes & Earthquakes A volcano Is an opening in earth’s surface that lets hot, melted rock and gases escape. When erupted the mountain can be destroyed of changed. The shaking of the ground is an earthquake. This happens when the earth’s crust shifts at a fault. Wide cracks may open in the ground and sometimes even destroy buildings, roads and bridges.

Constructive Process Deposition is the dropping of sediment or particles by water, wind, or ice. A delta is a deposit of sediment that builds up at a rivers mouth a flat piece of land. Floodplain is when the deposit of a sediment forms a wide, flat area of land. Longshore current is a current that moves parallel to the shore.

Continued……… Barrier island is a long, narrow island that forms along the coast. A sand dune is a hill of sand deposited by wind. A moraine is a ridge of sediment and rock left behind when a glacier melts. A dam is a structure built across a river to control its flow.

Controlling Processes that change the land A levee is a raised band of earth built along the edges of a river to prevent flooding. Beaches that erosion has eaten away are reclaimed. Sands from the ocean or nearby rivers are placed on the beach to rebuild it. This is called beach nourishment.

Living with earthquakes and volcano Seismologists study earthquakes. Seismologists study seismic waves, which are waves of energy that travel through Earth’s crust. Seismographs measure and record seismic waves. A seismogram is the record made by a seismograph. Scientist study seismograms to find out the size of an earthquake. It also helps them to figure out where faults exist in Earth’s crust. A tsunami is a huge wave caused by an earthquake under the ocean.