ND Study guide chap 7

In August 1986, a gigantic volume of __________ belched forth from Lake Nyos in Cameroon and swept down the adjacent valleys asphyxiating 1,700 people. A) sulfur dioxide B) carbon dioxide C) hydrogen sulfide D) carbon monoxide E) super-heated H2O

B) carbon dioxide

The vulcanian eruption of Eyjafjallajökull in southern Iceland in 2010 resulted from __________. A) an increase in subduction B) glacial meltwater pouring into the magma chamber C) temperature of the magma increasing D) an earthquake

B) glacial meltwater pouring into the magma chamber

Most of the people killed by the Mount St. Helens eruption of 1980 __________. A) were burned by lava flows B) had gone around barriers meant to keep people out of 'harms' way C) were scientists on top of the mountain D) were in a town thought to be within a safe-zone E) drowned when a large dam failed

B) had gone around barriers meant to keep people out of 'harms' way

Why are low latitudes the most dangerous latitudes to have a large volcanic eruption occur?A) Ash and gases from low-latitude eruptions are spread around Earth to the greatest degree. B) Explosions there are able to change Earth's tilt by a few degrees. C) Seismic waves generated by explosions there are able to travel to both hemispheres. D) The warmer temperatures there make the released gases more dangerous. E) The lack of snow and ice allows lava to do more damage before it cools.

A) Ash and gases from low-latitude eruptions are spread around Earth to the greatest degree.

What was the origin of the gas that killed 1,700 people in Cameroon in 1996? A) It leaked upward from basaltic magma underlying a lake. B) It flowed down the side of an erupting volcano. C) It was released from a geyser in a nearby national park. D) It was released in a lateral blast of a cinder cone. E) It was formed when acid rain fell on volcanic soils.

A) It leaked upward from basaltic magma underlying a lake.

In the United States, there was great concern in the early 1980s when earthquakes were frequent, including harmonic tremor, and four magnitude 6 earthquakes caused damage near __________. A) Long Valley Caldera in California B) Valles Caldera in New Mexico C) Yellowstone National Park, Wyoming D) Mt. St. Helens, Washington E) Crater Lake, Oregon

A) Long Valley Caldera in California

On 8 May 1902, a massive eruption of __________ killed 30,000 people in the town of St. Pierre. A) Mont Pelée, Martinique, B) Vesuvius, Italy, C) Krakatau, Indonesia, D) Mt. St. Helens, Washington, E) Nevado Del Ruiz, Colombia,

A) Mont Pelée, Martinique,

A genuine success story of advance warning before a large eruption occurred in the Philippines in 1991 before the climactic eruption of _________________. A) Mt. Pinatubo B) Nevado Del Ruiz C) Mont Pelée D) Mt. Mayon E) Popocatepetl

A) Mt. Pinatubo

Seafloor spreading generates __________ magma.

A) basaltic

Several geologic phenomena are being studied as signs of an impending volcanic eruption. These include seismic waves, ______________, and the release of gases. A) ground deformation B) flash floods C) landslides D) crystallization rates E) unusual animal behavior

A) ground deformation

Most Icelandic eruptions are __________. A) peaceful fissure eruptions B) super-eruptions C) explosive rhyolitic eruptions D) Plinian eruptions

A) peaceful fissure eruptions

Dome collapse, overspilling crater rim, direct blast, and eruption column collapse are all ways to generate __________. A) pyroclastic flows B) lava flows C) fissure eruptions D) felsic magma E) mafic magma

A) pyroclastic flows

The Mt..Pinatubo endangered people, animals, and property when its 1991 eruption resulted in __________. A) massive lava flows B) lahars and pyroclastic flows C) acid rain D) pelting lapilli E) the release of poisonous gases

B) lahars and pyroclastic flows

Active volcanoes today in Oregon and Washington, including Mt. St. Helens, result from _________________ .A) heat generated by friction on the San Andreas Fault B) the subduction of the Juan de Fuca Plate beneath North America C) the subduction of the Pacific Plate beneath North America D) spreading of the Juan de Fuca Ridge E) continent-continent collision

B) the subduction of the Juan de Fuca Plate beneath North America

The Toba eruption 74,000 years ago may have __________. A) reversed the flow of the Gulf Stream B) caused a reversal of Earth's magnetic field C) caused a great reduction in the worldwide human population D) been Earth's first super-eruption E) started the Ice Age

C) caused a great reduction in the worldwide human population

The energy behind the 1902 pyroclastic flow that destroyed St. Pierre came from _________________. A) the blast of the volcano B) gravity C) gas escaping from pieces of airborne pyroclastic material, creating a "popcorn" effect D) All of these choices are correct.

D) All of these choices are correct.

During the 1990s, hundreds of trees were killed at Mammoth Mountain, California, by the diffuse emission of _________ gas. A) O2 B) SiO2 C) CO D) CO2 E) H2S

D) CO2

The two most active Cascade Range volcanoes over the past 4,000 years are _______. A) Mt. Rainier and Mt. Adams B) Mt. Shasta and Mt. Jefferson C) Mt. Baker and Mt. Hood D) Mt. St. Helens and Mt. Shasta E) Lassen Peak and Newberry Volcano

D) Mt. St. Helens and Mt. Shasta

In 1985, __________ produced a minor eruption that melted part of a glacier near its summit, sending a lahar down its slopes and killing at least 22,000 people. A) Vesuvius, Italy, B) Mont Pelée, Martinique, C) Mt. Mayon, Philippines, D) Nevado Del Ruiz, Colombia, E) Popocatepetl, Mexico,

D) Nevado Del Ruiz, Colombia,

Volcanic eruptions with which of the following VEIs happen the most often? A) VEI of 4 B) VEI of 5 C) VEI of 6 D) VEI of 3

D) VEI of 3

What is the volcanic explosivity index (VEI) of a Yellowstone super-eruption? A) VEI of 2 B) VEI of 4 C) VEI of 6 D) VEI of 8

D) VEI of 8

Mt. Rainier, Washington, is number one on the danger list of many U.S. volcanologists because of its __________. A) great height B) extensive glacial cap C) frequent earthquakes D) active hot-water spring systems, which have weakened the mountain internally E) All of these choices are correct.

E) All of these choices are correct.

Violent causes of death from volcanic eruptions include _______________. A) pyroclastic flows' B) tsunami C) lahars D) poison gases E) All of these choices are correct.

E) All of these choices are correct.

During the summer of 1783, the greatest lava eruption of historic times poured forth at _________, accompanied by the release of an enormous volume of gases that enshrouded much of northern Europe in a "dry fog" or blue haze rich in SO2 (one of the visible components of today's urban smog).' A) Mont Blanc, France B) Vesuvius, Italy C) Stromboli, Italy D) Ararat, Turkey E) Laki, Iceland

E) Laki, Iceland

Viscous magmas are stored as a mostly solid, crystalline mush. It can be activated by which of the following? A) an injection of new, hot magma B) an injection of seawater C) fracturing by fault movements that connect to isolated magma bodies and reduce the pressure D) a massive increase in spreading center rates E) an injection of new, hot magma and fracturing by fault movements that connect to isolated magma bodies and reduce the pressure

E) an injection of new, hot magma and fracturing by fault movements that connect to isolated magma bodies and reduce the pressure

In 1883, __________ exploded and the resulting tsunami killed 36,000 people on Java and Sumatra. A) Tambora B) Pelée C) Santorini D) Toba E) Krakatau

E)Krakatau