DEFINITIONS+AND+QUESTIONS+FROM+UNIT+7

QUESTIONS FROM PAGE 95 and 97:

PAGE 95 1.- **Earthquake:** It is a movement of the land caused by forces involved in the Earth´s dynamics which can be destructive. **Seismic:** Vibration of the Earth **Seismograph or seismometer:** //It is a tool that measures an earthquake´s durations and magnitude.// //**Seismology:** The branch of geology concerned with the study of earthquakes.// //**Seismic resistant**: A building whose design and components allow it to withstand the effects of an earthquake.//

//2.- Explain how an earthquake occurs.//

//PAGE 97// 1.-**Magma:** It is a mass of molten rock and gases found under the surface of the Earth. When magma erupts to the surface, it is called, lava. **Lava:** It is a mass of degassed magma. It is the hot, liquid molten rock which is ejected when a volcano erupts.


 * Pyroclast: ** A fragment of solid material ejected during a volcanic eruption or a piece of lava that is thrown into the air and solidifies before it hits the ground.


 * Flow: ** A stream of lava which moves down the sides of a volcanic cone when a volcano erupts and which forms a field of volcanic rock as it solidifies.

2.- **A volcanic cone** is a mountain-like, generally cone-shaped structure formed by an accumulation of volcanic material. **A volcano** is an opening in the planet´s surface through which molten rock from the inside the Earth escape from below the surface and accumulate to form a volcanic cone.