| A | B |
|---|
| earthquakes | the shaking that results from the movement of rock beneath Earth's surface |
| stress | a force that acts on rock to change its shape or volume |
| deformation | a change in the volume of shape of Earth's crust |
| shearing | stress that puches amass of rock in oppositedirections |
| compresion | stress that squezzes rock until it folds |
| fault | a break in the earth's crust where slabs of rock slip past each other |
| strike-slip fault | a type of fault where rocks on either side move past each other sideways with little up or down motions |
| normal fault | a type of fault where the hanging wall slides downward |
| hanging wall | the block of rock that forms the upper half of a fault |
| footwall | the block of rock that forms the lower half of the fault |
| reverse fault | a type of fault where the hanging wall slides upward |
| fault-block mountian | a mountain that forms where a normal fault uplifts a block of rock |
| folds | a bend in rock that forms where part of the earth's crust has been compressed |
| anticline | an upward fold in a rock formed by compression in the earth's crust |
| syncline | A downward fold in the rock, formed by compression in the earth's crust |
| plateau | a large area of flat land elevated high above sea level |
| liquefication | the process by which an earthquake's violent movement suddenly turns loose soil into liquid mud |
| aftershock | an earthquake that occurs after a large earthquake in the same area |
| tsunamis | a large wave produced by an earthquake on the ocean floor |
| base-isolated building | a building mounted on bearings, designed to absorb the energy of an earthquake |
| focus | the point beneath the earth's surface where rock breaks under stress and causes an earthquake |
| epicenter | the point on the earth's surface directly above an earthquake's surface |
| seismic waves | a vibration that travels through the earth carring the energy realesed by an earth quake |
| P waves | A type of seismic wave that compresses and expands the ground |
| S waves | a type of seismic wave that moves the ground up and down or side to side |
| surface waves | a type of seismic wave that forms when P waves and S waves reach the surface |
| seismogragh | a device that records ground movements caused by seismic waves |
| magnitude | the measurement of an earthquake's strength based on seismic waves and movement along faults |
| Mercalli scale | a scale that rates earthquakes according to intensity and damage caused |
| Richter scale | a scale that rates seismic waves as measured by a particular kind of mechanical seismograph |
| moment magnitude | a scale that rates earthquakes by estimating the total energy released |
| volcano | a weak spot in the earth's crust where magma has come to the surface |
| lava | liquid magma that reaches the surface |
| island arc | a string of islands formed by the volcanoes along a deep ocean trench |
| magma | the molten mixture of rock forming substances, gases, and water from the mantle |
| Ring of Fire | a major belt of volcanoes that rims the Pacific Ocean |
| hot spot | an area where magma from deep within melts through the crust above it |
| shield volcano | a wide, gently sloping mountain made of layers of lava and formed by quiet eruptions |
| cinder cone | a steep cone shaped hill or mountain made of volcanic ash, cinders, and bombs piled up around a volcanoe's opening |
| composite volcano | a tall, cone shaped mountain in which layers of lava alternate with layers of ash and other volcanic material |
| caldera | a large hole at the top of a volcano |
| volcanic neck | a deposit of hardening magma in the volcano's pipe |
| dike | a slab of volcanic rock formed when magma forces itself across rock layers |
| sill | a slab of volcanic rock formed when magma squeezes between layers of rock |
| batholith | a mass of rock formed when a large body of magma cooled inside the crust |
| magma chamber | the pocket beneath the volcano where magma collects |
| pipe | a long tube through which magma moves from the magma chamber to the earth's surface |
| vent | the opening through which molten rock and gas leave the volcano |
| lava flow | the area covered by lava as it pour out of a volcano's vent |
| crater | a bowl shaped area that forms around a volcano's central opening |
| silica | a material that is formed from the elements oxygen and silicon |
| pahoehoe | a hot, fast moving type of lava that hardens to form smooth, rope-like coils |
| aa | a slow moving type of lava that hardens to form rough chunks -- cooler than a pahoehoe |
| pyroclastic flow | the expulsion of ash, cynders, bombs, and gas during an explosive volcano eruption |
| extinct | said of a volcano when it is unlikely to erupt again |
| hot spring | a pool formed by ground water that has risen to the surface after being heated by a nearby body of magma |
| geyser | a fountain of water and steam that builds up under pressure under ground and erupts at regular intervalsu |
| geothermal energy | energy from water and steam that has been heated by magma |
