Chapter 2: Geology Flashcards
1
Q
The study of the earth
A
Geology
2
Q
The 3 major layers of the earth based on composition
A
Crust, mantle, and core
3
Q
Outer layer of the earth made of solid rock
A
Crust
4
Q
Deposits of sand, mineral fragments, or organic materials usually left by wind or water that can be found in the earth’s crust
A
Sediments
5
Q
The most abundant element in the earth’s crust
A
Oxygen
6
Q
Type of crust composed of granite (silica and aluminum oxide)
A
Continental crust
7
Q
Type of crust composed of basalt and gabbro
A
Oceanic crust
8
Q
Middle layer of the earth
A
Mantle
9
Q
Earthquake vibrations used to determine what lies beneath the earth’s crust
A
Seismic waves
10
Q
Lower boundary of the crust that marks the change in rock density within the earth (Hint: Croatia)
A
Moho, or Mohorovičić discontinuity
11
Q
The first person to use seismic waves to map the earth’s interior
A
Andrija Mohorovicic
12
Q
The middle layer of the earth
A
Mantle
13
Q
The area between the upper and lower mantle that marks where the two portions merge
A
Transition zone
14
Q
The rocks of the mantle that flow more like a thick, syrupy liquid in slow motion
A
Plastic rock
15
Q
The deeper you go in the earth, the ____________ the temperature becomes.
A
Higher
16
Q
The lower boundary of he mantle that marks yet another change in the earth’s density
A
Core-mantle boundary, or Gutenberg discontinuity
17
Q
The central part of the earth
A
Core
18
Q
Layer of the core that is assumed to be composed of molten (liquid) iron and nickel
A
Outer core
19
Q
Layer of the core that is assumed to be composed of solid iron and nickel
A
Inner core
20
Q
Portions of solid rock that float like rafts on the plastic rock of the upper mantle
A
Tectonic plates
21
Q
A region of the earth’s crust and upper mantle composed of rigid plates
A
Lithosphere
22
Q
The plastic rock hat forms the lower portion of the upper mantle
A
Asthenosphere
23
Q
Theory that the plates and their movements affect geologic structures and processes
A
Plate tectonics
24
Q
The fracture zone that results from layers of rock breaking and moving due to the strain of forces upon it. The boundary between stationary rocks and moving rocks
A
Fault
25
Type of fault that occurs when rocks along one side of a fault sink vertically (often results in cliffs)
Normal fault
26
Type of fault that occurs when rocks along one side of a fault move horizontally along a fault
Strike-slip fault
27
Type of fault caused by rocks on one side of a fault being shoved on top of the rocks on the other side.
Thrust fault
28
The result of the bending or buckling of rock under great force
Fold
29
Rocks that bend downward in the folding process for a trough-like structure called a ____________.
Syncline
30
Rocks that buckle upward during folding form an arch-like structure called a(n) ________________.
Anticline
31
Elevated land masses that are higher than hills
Mountains
32
Formed when molten rock erupts from the earth’s crust
Volcanic mountains
33
Formed when molten rock is formed beneath an overlying rock layer, forcing that rock layer upward into a blister like shape
Domes mountain
34
Formed when the edges of two adjacent tectonic plates were pushed together, causing the layers to buckle
Folded mountains
35
Formed when rocks along one side of a fault are forced upward while the rocks on the other side sink
Fault-block mountain
36
Maps that show an area’s elevation, natural features, and man-made structures
Topographic maps
37
A computer system that stores and processes geographic data
Geographic information system (GIS)
38
Earthquakes that result from the sudden movements of rock beneath the earth’s surface
Tectonic earthquakes
39
A weak earthquake
Tremor
40
Smaller earthquakes or tremors
Aftershocks
41
The study of earthquakes
Seismology
42
Sudden movement of rock masses along a fault
Faulting
43
Theory that rocks on either side of a fault spring back to a position of little or no strain at the moment of an earthquake, triggering vibrations in the earth’s crust
Elastic rebound theory
44
Famous strike-slip fault in western California
San Andreas fault
45
Rocks along a fault that may be polished smooth by rapid movement of the earth’s crust (due to horizontal pressure)
Slickensides
46
The point where an earthquake begins underground
Hypocenter
47
The point above ground where an earthquake begins
Epicenter
48
The 3 earthquake classifications
Shallow-focus, intermediate-focus, and deep-focus
49
The most active narrow belt or zone where nearly 80% of all earthquakes occur
Circum-Pacific belt
50
Earthquake zone that stretches from Southern Europe into Asia
Alpide belt
51
The fastest earthquake waves that occur in a rhythmic push-pull motion
P waves, Primary waves
52
Earthquakes that consist of rhythmic side-to-side motion, occurring at right angles to the direction that the waves travel
S waves, secondary waves
53
The slowest earthquake waves that are very similar to ocean waves in their movement
Surface waves
54
Instrument used to record earthquakes
Seismograph
55
Device connected to a seismograph that detects the earth’s movements
Seismometer
56
The record produced by a seismograph
Seismogram
57
Computer system that calculates the epicenter and strength of an earthquake and sends out an alert to those who will soon be affected by the earthquake
Earthquake early warning system, (EEW system)
58
The scale with twelve degrees of intensity based on human reactions and structural damage (non-mathematical)
Modified Mercalli scale (MM)
59
Scale used to measure earthquake strength mathematically
Richter magnitude scale (or local magnitude scale)
60
The most reliable method for measuring an earthquake’s magnitude
Moment magnitude scale
61
Building systems constructed on bedrock
Fixed-based systems
62
Building systems resting on isolators that absorb the seismic energy
Base-isolated systems
63
What are the moveable “stilts” that separate a building from its foundation
Isolators
64
Engineering devices that are added to structures to absorb some of the seismic energy to lessen the stress on the building, minimizing deformation
Energy-dissipating devices
65
An opening in the earth’s surface through which hot gases, ash, and molten rock are ejected from the earth’s interior
Volcano
66
The channel through which gases, ash, and rock are ejected
Vent
67
Molten rock beneath the earth’s surface
Magma
68
Reservoir of molten rock located several kilometers beneath the surface
Magma chamber
69
What is the actual source of a volcanic eruption?
The underground magma chamber
70
The study of volcanoes and volcano-related phenomena
Volcanology
71
Scientists who study volcanoes
Volcanologists
72
Which kind of volcanoes consist primarily of erupted volcanic ash and rock fragments (cinders)?
Cinder-cone volcanoes
73
A volcano that pours out large quantities of highly fluid lava in rather mild eruptions produces a broad, gently sloping cone called a…
Shield volcano
74
Symmetrical, wide-based mountains that consist of alternating layers of lava and cinders
Composite volcanoes (stratovolcanoes)
75
If a volcano has erupted within recorded history or is currently producing seismic activity, it is considered to be
Active
76
An inactive volcano that could erupt again is classified as
Dormant
77
A volcano that will probably not erupt again is classified as
Extinct
78
A narrow zone of active volcanoes that parallels the circum-Pacific belt where more than half of the world’s active volcanoes are in this belt
the Ring of Fire
79
The violence of a volcano’s eruption depends upon which two factors?
1. Viscosity of the magma
2. Amount of dissolved gas in the magma
80
Will magma with low viscosity have a violent or gentle lava flow?
Gentle lava flow
81
Will magma with a high viscosity have a violent or gentle lava flow?
Violent lava flow
82
Any substance emitted by an active volcano
Ejecta
83
What are the three different types of ejecta?
Gases, liquids, and solids
84
The molten rock that flows from volcanoes
Lava
85
The lava that hardens to form either a smooth surface or a ropy surface
Pahoehoe
86
Lava that hardens into rough, jagged rocks with a crumbly texture
Aa
87
Occasionally lava is emitted underwater or flows into the ocean or a lake before solidifying almost instantly and forming rounded structures resembling pillows
Pillow lava
88
General term for particles or blocks of solid volcanic ejecta
Pyroclasts
89
Tiny droplets of lava that form fine Pyroclastic particles less than 2 mm (0.08 in). They are light enough to be carried long distances by the wind.
Volcanic ash
90
Ejecta that are larger than 2mm but less than 64mm in diameter
Lapilli
91
Solid, irregularly shaped lumps of hardened lava, often large and boulder-like. They form when lava hardens within the volcano.
Volcanic blocks
92
Pyroclastic ejecta that form when lava is hurled into the air then hardens into rock before it hits the ground. They have a rounded “almond” or “teardrop” shape
Volcanic bombs
93
This phenomenon consists of a superheated cloud of gas and volcanic ash that travels swiftly down the volcanic slope as an avalanche.
Pyroclastic flow
94
A scale to measure the explosiveness of a volcano’s eruptions
Volcanic Explosivity Index (VEI)
95
Huge bowl-shaped craters that are thought to form when the magma chamber beneath a volcano is emptied of magma, causing it to collapse under its own weight.
Calderas
96
Geological features that form when the surface of a large lava flow hardens but the lava beneath remains molten and continues to flow
Lava tunnels (or lava tubes)
97
Magma that forces its way through cracks and weak spots in the rocks surrounding the magma chamber and solidify producing masses of volcanic rock beneath the surface
Igneous intrusions
98
When volcanic magma that hardens in a vertical crack or fissure, it forms a vertical, sheet-like mass of igneous rock called a _____.
Dike
99
When magma squeezes between two horizontal layers of rock, it forms a horizontal, sheet-like mass of igneous rock called a(n) _______.
Sill
100
Unusually stiff magma that does not spread enough to form a sill, instead bulges the overlying rocks upward to produce a dome-like intrusion
Laccolith
101
Igneous intrusions similar to laccoliths, but far larger
Batholiths
