ESC 1000 Test 2 Study Guide
Approximately how much more energy is released in a 6.5 Richter magnitude earthquake than in one with magnitude 5.5?
30 times
________ destroyed the city of St. Pierre, Martinique, in 1902.
A nueé ardente
The ________ area geologically old mountain range folded and deformed during the Paleozoic.
Appalachians in the eastern United States
________ magma is the most abundant type erupted on Earth.
Basaltic
Which of the following factors help determine whether a volcanic eruption will be violent or relatively quiescent? A) temperature of the magma B) amount of dissolved gas in the magma C) composition of the magma D) all of these
D) all of these
Which one of the following is an important fundamental assumption underlying the plate tectonic theory?
Earth's surface has been essentially constant over time
The Mercalli Scale is a scale from ________.
I to XII that rates the structural damage due to an earthquake
________ was never proposed as evidence supporting the existence of Pangaea.
Islands of Precambrian rocks along the Mid-Atlantic Ridge
________ was an ancient reptile that lived in South America and Africa during the late Paleozoic.
Mesosaurus
In 1980, ________ was the first Cascade Range volcano to erupt since Mt. Lassen in 1915-16.
Mt. St. Helens
On a typical seismogram, ________ will show the highest amplitudes.
P waves
The former late Paleozoic supercontinent is known as ________.
Pangaea
The ________ is (are) a logical evolutionary analog of the African Rift Valleys ten million years from now.
Red Sea
The elastic rebound theory for the origin of earthquakes was first proposed by ________ following the ________ earthquake.
Reid; 1906, San Francisco
The ________ magnitude scale is a measure of the energy released. It does not directly measure the extent of building damage.
Richter
Which one of the following statements is correct?
S waves travel through solids and P waves travel through liquids
The ________ in California is the boundary between the North American and Pacific plates.
San Andres strike-slip fault
The ________ earthquake was accompanied by extensive fire damage.
San Francisco, 1906
________ is a major dissolved volatile constituent in both magmas and volcanic gases.
Water
________ are usually the most abundant gases emitted during basaltic volcanism.
Water and carbon dioxide
________ is the maximum possible damage designation on the Mercalli scale.
XII
A graben is characterized by ________.
a hanging wall block that has moved down between two normal faults
Which type of basaltic lava flow has its surface covered with sharp-edged, angular blocks and rubble?
aa
The Richter magnitude of an earthquake is determined from the ________.
amplitude of the largest seismic waves
Mount St. Helens is ________.
an explosive stratovolcano
The average composition of rocks comprising a large composite cone or stratovolcano is similar to a(n) ________ magma.
andesitic
Spreading center volcanism most generally produces rocks that are ________.
basaltic in composition
Mount Pelée on Martinique is an example of a ________.
composite volcano
The Aleutian Islands occur at a ________.
convergent boundary on a volcanic arc above a northward-subducting Pacific plate
Brittle deformation would be favored over plastic deformation in which of the following conditions?
cooler temperatures
Pull-apart rift zones are generally associated with a ________ plate boundary.
divergent
New oceanic crust and lithosphere are formed at ________.
divergent boundaries by submarine eruptions and intrusions of basaltic magma
Which statement about the May, 1980, eruption of Mount St. Helens is false?
during the eruptive period, the mountain peak was substantially built up by new lava flows and pyroclastic debris
The mechanism by which rocks store and eventually release energy in the form of an earthquake is termed ________.
elastic rebound
Which of the following energy sources is thought to drive the lateral motions of Earth's lithospheric plates?
export of heat from deep in the mantle to the top of the asthenosphere
The Sierra Nevada, California, and Teton, Wyoming, ranges are examples of ________.
fault blocks uplifted by late Tertiary to Quaternary normal faulting
The Columbia Plateau in the northwestern United States is an excellent example of ________.
flood basalts
A very long-lived magma source located deep in the mantle is called a ________.
hot spot
The concept that rocks of the crust and upper mantle are floating in gravitational balance is known as ________.
isostasy
Which one of the following statements about the crust is NOT true?
oceanic crust is rich in potassium, sodium, and silicon
Magma tends to rise toward Earth's surface principally because ________.
rocks become less dense when they melt
The record of an earthquake obtained from a seismic instrument is a(n) ________.
seismograph
A ________ fault has little or no vertical movements of the two blocks.
strike slip
Which region has the greatest concentration of currently active volcanoes?
the circum- Pacific area
In thrust faulting, ________.
the crust is shortened and thickened
In a normal fault ________.
the hanging wall block above an inclined fault plane moves downward relative to the other block
Early results of the Deep Sea Drilling Project clearly justified the conclusion that ________.
the ocean basins are relatively young; no seafloor with an age in excess of 180 million years was ever found
Which one of the following is true regarding tsunamis?
they occur in the open ocean, wavelengths are many miles or kilometers and wave heights are only a few feet
Which one of the following is an example of an isostatic movement?
uplift of areas recently covered by thick, continental ice sheets
The ________ is (are) characterized by terrane accretion that has been active throughout most of Mesozoic and Cenozoic time.
western margin of North America
Mount St. Helens and the other Cascade volcanoes are ________.
young, active stratovolcanoes built on a continental margin above a sinking slab of oceanic lithosphere