| A | B |
|---|
| crust | The layer of earth we walk on, including the rock of the ocean floor and large areas of land called continents |
| mantle | The thickest layer of the planet; composed mostly of solid rock and some partially melted rock |
| plates | Earth's crust and upper mantel broken into continent-sized slabs that move slowly across earth's surface on a thin layer of partially melted mantle |
| San Andreas fault | a fault that runs through many miles of desert and mountains in southern California. The frequent earthquakes there are caused by quick large movements of the 2 pieces of earth's crust that form the fault. |
| fault | a break in the crust along which rock moves and most earthquakes occur |
| seismograph | an instrument that records earthquake waves |
| tsunamis | A series of large sea waves caused by an underwater earthquake or a volcanic eruption. |
| storm surge | Very large waves which occur during hurricanes or tsunamis that cause a lot of damage along the shore. Storm surges cause flooding, erosion, and deposition along a shore. |
| erosion | Carrying away of sediments |
| weathering | The action of water and wind on exposed rock that causes the rock to erode. |
| deposition | Dropping off or deposit of sediments (rock particles and soil) by waves, wind, running water or glaciers. |
| volcano | A mountain that forms when red-hot melted rock flows through a crack and onto Earth's surface. |
| magma | Melted rock inside Earth |
| ring of fire | an area of intense volcanic activity |
| continental shelf | The shallow underwater edge of all continents |
| abyssal plains | The large flat part of the ocean floor that is covered with a thick layer of sediments of clay, silt, sand, and rock carried into the oceans from the continents |
| trenches | Deep canyons on the ocean floor that are formed when 2 of Earth's ocean plates collide and one plate slides beneath the other. |
| dam | A barrier built across a river to control the flow of water, or hold back the water for later use. |
| constructive | improvement or development |
| destructive | causing destruction |
| core | a dense ball deep inside the earth made of mostly iron and nickel |
| Mid-Atlantic Ridge | a long chain of mountains that runs aling the ocean floor in the middle of the Atlantic Ocean. It formed where 2 plates of Earth's crust are moving apart. |
| earthquake | a vibration, or shaking or Earth's crust |
| seismologist | a scientist who monitors and records earthquake intensity to help reduce earthquake hazards |
| lava | melted rock that reaches Earth's surface |
| shore zone | the place where land and ocean meet that is rich in resources such as fish, oils, fertilizer, salts, and sand. The ocean floor of this area is called the continental shelf |
| continental slope | located at the edge of a continental shelf where the ocean floor drops away rapidly |
| Mid-ocean Ridge | world's largest mountain range. The island country of Iceland is one of the dew places on Earth where the mid-ocean ridge rises above the ocean's surface. |
| seamounts | steep-sided volcanic mountains that rise above the abyssal plain |
| glacier | a large mass of ice and snow that moves over land leaving distinctive features on the Earth's surface. Continental glaciers flatten and round the land, while other glaciers carve U-shaped valleys and steep cliffs. |
| delta | sand, silt, gravel, or other small particles picked up from far away and deposited by running water at the mouth of a river. |
| sand dunes | wind-blown sand that hits an obstacle and piles up into a mound or ridge |
| levee | a bank built along a river to protect land from flooding; usually covered with concrete, it creates a tall wall designed to prevent flooding. It takes a massive amount of water the break a levee system |
| mudslide | They can occur during a flood. They happen along a slope area of land that is saturated with water. They begin to slide slowly at first, but quickly pick up speed. As a mudslide moves, it picks up large amounts of land. They can can get big enough to cover a 30 foot building! |
