Chapter 14 - GEO 200
The Alaskan earthquake of 1964 was extraordinarily violent and has been assigned a moment magnitude of ________. 2.3 47.5 21.6 5.7 9.2
9.2
Crater Lake, Oregon, is an example of a volcanic ________. caldera neck batholith peak lava flow
Caldera
What are the four basic types of volcanoes and their characteristics?
Composite cone - consist of a mix of lava flows and pyroclastic materials Shield volcano - composed of lavas and relatively little ash or cinders and gentle slopes Plug domes - extrude extremely stiff acidic lava that fills the initial pyroclasitc cone and steep sided Cinder cones - smallest type, produces litle lava and consists largely of pyroclastics
A fault is any break in the Earth's surface or crust. True False
False
Prior to Mt. St. Helens in 1980 there had never been an active volcano in the United States. True False
False
What is the difference between "folding" and "faulting?"
Folding is the wrinkling of the earth's surface from slow lateral compression - faulting is the rupture or breaking of the earth's surface from faster process.
A crustal block which is downthrown with a steep fault scarp on either side is a ________. horst fault block mountain graben rift valley syncline
Graben
Similar in nature to a batholith but much smaller in size is a ________. vein sill stock dike all of the above
Stock
________ is an area of extensive flood basalts.
The Deccan Plateau The Columbia Plateau
A foreshock sometimes comes before a major earthquake. True False
True
A simple symmetrical upfold in topography is an anticline. True False
True
Deep fault zones apparently serve as conduits allowing water and heat to approach the surface. True False
True
In the Cascade Range, there are many peaks larger or taller than Mount Saint Helens which exploded. True False
True
The Earth's crust is rigid as compared to the mantle directly underneath. True False
True
The largest recorded earthquake had a moment magnitude of 9.5 and occurred in Chile. True False
True
The southern portion of the "super continent" envisioned by Wegener is called Gondwanaland. True False
True
On the Modified Mercalli scale, the largest earthquakes would be assigned a value of ________. 10 3 1 8.5 XII
XII
In earthquakes, P waves________. arrive more slowly than surface waves are absent are also known as surface waves are faster than S waves travel towards the focus
are faster than S waves
Presently, the North American and Eurasian plates are moving ________. toward each other toward the Equator nowhere away from each other toward the North Pole
away from each other
The ________ is an igneous intrusion which has a surface area of at least 100 square kilometers. vein butte stock laccolith batholith
batholith
The most massive form of igneous intrusion is a ________. batholith sill none of the above stock laccolith
batholith
Radial walls extending outward from a volcano are ________. veins dikes plugs clay pans sills
dikes
A(n) ________ is an abrupt movement of the Earth's crust usually associated with a fault zone.
earthquake
ava flows often create ________. volcanoes batholiths volcanic necks flattish plains dikes
flattish plains
Grabens are commonly found in association with ________. batholiths concretions horsts sag ponds anticlines
horsts
A volcanic mudflow is known as a(n) ________.
lahar
Currently, the rate of sea-floor spreading in the Atlantic is thought to be: 0 centimeters per year (stopped). 100 meters per year. 10 meters per year. less than 1 centimeter per year. 1 kilometer per year.
less than 1 centimeter per year.
Mt. St. Helen's is ________. the largest volcano in the world dead the world's best example of intrusive vulcanism scheduled to erupt in the year 2050 likely to vigorously erupt again
likely to vigorously erupt again
A ________ is a one-sided fold connecting horizontal or gently inclined strate. overthrust symmetrical fold monocline anticline syncline
monocline
Volcanic activity that takes place deep under the crust is termed ________. pyroclastic plutonic intrusive subduction metamorphic
plutonic
The totality of materials ejected from a volcano, including liquid material, ashes and dust is termed ________. granite magma pyroclastic material lava silica
pyroclastic material
A lengthy complex of grabens forms a ________ valley.
rift
Water collected in small bodies along a recently active fault line forms ________. sills sag ponds dikes reservoirs playas
sag ponds
Instead of the vertical displacement of other faults, a ________ fault has horizontal displacement between the two sides
strike-slip
Relatively cooler magma in an erupting volcano is apparently the result of ________. depth of magma formation the amount of water present the relatively high amount of silica present position of astronomical bodies surface salinity
the relatively high amount of silica present
A ________ plate boundary is associated with lateral slippage, conservation of existing crust, and the San Andreas fault system? fault scarp transform divergent subducting convergent
transform
The Andesite Line refers to the numerous volcanoes which dot the rim of the Pacific Ocean. True False
true