| A | B |
|---|
| compression | squeezes rock until it folds or breaks |
| aftershock | an earthquake that occurs after a larger earthquake in the sam place. |
| Normal fault | where tension pulls rock apart and the fault is at an angle |
| hanging wall | the block of rock above the fault in a normal fault |
| stress | a force that works on rock to change its shape or volume |
| Shearing | stress that pushes a mass of rock in two opposite directions |
| strike slip fault | a fault where rock moves sideways with little up or down motion |
| tension | stretches rock so that it become thinner in the middle |
| syncline | a downward fold in a rock caused by compression |
| anticline | an upward fold in rock caused by compression |
| plateau | a large area of flat land elvated high above sea level |
| Footwall | the rock that lies below the fault |
| Earthquake | the shaking and trembling that results from rock moving beneath the earth's surface |
| Focus | the point under earth's surface where rocks breaks causing an earthquake |
| epicenter | the point on earth directly above the focus |
| P waves | compressand expand like an accordion |
| S waves | Vibrate side to side and up and down |
| surface waves | can roll earth's surface like an ocean wave |
| mercalli scale | rates an earthquake's damage |
| richter scale | measures an earthquakes magnitude |
| magnitude | a number scientists give an earthquake to measure its size |
| seismograph | measures and records seismic waves |
| reverse fault | where compression pushes rock together |
| seismogram | the record of seismic waves produced by a seismograph |
| friction | the force that opposes the motion of one surface as it moves across another surface |
| liquifaction | when loose soil turns into liquid mud |
| moment magnitude scale | measures the total energy released by an earthquake |
| Volcano | a weak spot in Earth's crust where molten material rises to the surface |
| geyser | a fountain of water and steam that erupts from the ground |
| lava | magma that has reached the surface |
| ring of fire | a major volcanic belt that rims the Pacific Ocean |
| island arc | volcanic islands that are created near a subduction zone |
| hot spot | where material from the rises and reaches the crust's surface |
| element | a substance that cannot be broken down into other substances |
| compound | a substance made up of two or more elements |
| physical properties | can be observed or measured without changing the composition of the substance |
| chemical property | and property that changes the composition of a substance |
| viscosity | the resistance of a liquid to flowing |
| silica | oxygen and silicon |
| pahoehoe | lava that flows easily, low viscosity |
| aa | slow moving lava with high viscosity |
| magma chamber | a pocket of magma beneath a volcano |
| pipe | a long pipe that connects the magma chamber to the surface |
| vent | an opening where magma and gases can escape |
| lava flow | an area covered by lava asi it flows from a vent |
| crater | a bowl shaped area that form around the central vent |
| pyroclastic flow | an explosive eruption |
| active | a live volcano |
| dormant | a sleeping volcano |
| magma | molten mixture of rock, gases and water from the mantle |
| shield volcano | a wide gently sloping mountain |
| cinder cone | a steep cone shaped hill or small mountain |
| composite volcanoes | tall cone shaped mountains that alternale layers of lava with layers of ash |
| lava plateau | high level areas of lava |
| caldera | a huge hole left by the collapse of a volcano |
| volcanic neck | When magma hardens in a volcanic pipe and the softer outer ock wears away |
| dike | magma that forces its way through rock layers and hardens |
| sill | when magma squeezes between horizontal layers of rock |
| batholith | a mass of rock that forms when a large body of magma cools inside the crust |
| geothermal activity | when magma underground heats water |
| exstinct | a dead volcano |
