EARTHQUAKES/VOLCANOES
VOCABULARY
1. active: said of a volcano that is erupting and shows signs of errupting in the near future.
2. aftershock: an earthquake that occurs after a larger earthquke in the same area
3. anticline: an upward fold in rock fromed by compression in Earth's crust
4. basalt: a dark,dense,igneous rock , with fine texture, found in oceanic crust
5. batholith: A mass of rock formed when a large body of magma cools inside the crust
6. caldera: the large hole at the top of the volcano formed when the roof of the volcano's magma
chamber collaspes
7. cinder cone: a steep cone shaped hill or mountain made of volcanic ash, cinders, and bombs piled
up at the volcano's opening
8. composite volcano: a tall, cone-shaped mountain in which layers of lava alternate with layers of
ash and other volcanic materials, also know as a stratavolcano
9. compression: the stress force that squeezes rock until it folds or breaks
10. crater: a bowl shaped area that forms around a volcano's central opening
11. deformation: any change in the volume or shape of the Earth's crust
12. dormant: a volcano that doen't show sighn of errupting in the near furture
13. earthquake: the shaking that results from the movement of rock beneath Earth's surface
14. epicenter: the point on Earth's surface directly above an earthquake's focus
15. extinct: said of a volcano that is unlikely to errupt again
16. fault: a break in the Earth's curst where slabs of rock slip past each other
17. fault-block mountain: a mountain that forms where a normal fault uplifts a block of rock
18. fold: a bend in rock that forms where part of Earth's crust is compressed
19. footwall: the block of rock that forms the lower half of a fault
20. geyser: a type of hot spring that builds up pressure underground and errupts at regular intervials as
a fountain of water and steam
21. hanging wall: the block of rock that forms the upper part of a fault
22. hot spot: an area where magma from deep within the mantle melts right through the crust above it
23. island arc: a string of islands formed by the volcanoes along a deep ocean trench
24. lava: liquid magma that reaches the surface
25. liquefaction: loose soft soil is turned into liquid mud during violent earthquakes
26. magma: a molten mixture of rock forming substances,gases, and water from the mantle
27. magma chamber: the pocket beneath a volcano where magma collects
28. normal fault: a fault on an angle, caused by tension, where the hanging wall slides downward.
Example: Rio Grande Rift Valley
29. P-wave: primary wave: a type of seismic wave that compresses and expands the ground
30. pyroclastic flow: the explusion of ash, cinders, bombs, and gases during on explosive volcanic
erruption
31. reverse fault: a fault at an angle, caused by compression, where the hanging wall moves upward
Example Aplalachain Mountains
32. richter scale: a scale that rates the seismic wavesas measured by a paticular type of mechanical
seismograph
33. ring of fire: a major belt of volcanos that rim the pacific ocean
34. s-wave: secondary wave; a type of seismic waves that moves the ground up and down or side to
side
35. shearing: the stress force that pushes a mass of rock in two opisite directions
36. sheild volcano: a wide gentle slopping volcano made of layers of lava and formed by quiet
erruptions.
37. silica: a material that is formed from the elements oxygen and silicon:silica is found magma and
sand
38. stress: a force that act on rock to change its volume or shape
39. strike-slip fault: a fault, caused by by shearing, where rocks on either side move past each other
sideways with little up and down motion. Example; San Andreas fault
40. surface waves: a type of seismic wave that forms when p-waves and s-waves reach Earth's surface
41. syncline: a downward fold in rock formed by compression in Earth's crust
42. tension: t he stress force that pulls on the crust, streching rock to make it thinner
43. Tsunami: large waves that are formed when water is displaced by earthquakes
44. volcano: a weak spot in the crust where magma has come to the surface