geol exam 2 ch 6-9

_________ are low-pressure air zones enclosed by somewhat circular isobars.

cyclones

Hawaiian volcanoes unlikely to erupt include _________________.

diamond head, oahu

A well-formed conical volcano located above an active subduction zone that has not erupted in 12,000 years is __________.

dormant but will likely erupt again at some point

Hawaiian volcanoes produce andesitic lava.

false

It is possible that a large hunk of Hawaii could be plunged into the sea following a large earthquake, generating a powerful tsunami.

false

While California has experienced many deadly earthquakes, it has never experienced fatalities from tsunami.

false

the higher the viscosity of magma, the more fluid is its behavior

false

Seafloor spreading generates __________ magma

felsic

Short-wavelength radiation from the Sun passes through a planet's atmosphere but some of the outgoing long-wavelength energy is absorbed and radiated again; this process is known as_________.

greenhouse effect

An anticyclone is a __________.

high pressure air zone enclosed by roughly circular isobars

The best course of action to take if you suspect a tsunami is headed your way is to __________.

higher ground

What was the origin of the gas that killed 1,700 people in Cameroon in 1996?

it leaked upward from basaltic magma underlying a lake

The altitude where 100% humidity is reached is the __________ level.

lifting condensation

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 __________.

long valley caldera in cali

The two most active Cascade Range volcanoes over the past 4,000 years are _______________.

mt helen and mt shasta

This volcano erupted in 1883 in the Sunda Strait between Sumatra and Java, exploding with a loudness heard 3,000 miles away, then collapsing into its magma chamber, making a caldera and setting off a tsunami that killed at least 36,000 people.

mt pele

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.

nevado del ruiz, colombia

__________ eruptions are the most violent types of explosive eruptions.

plinian-type

Within the Ferrel cell, surface air flows __________.

poleward

Dome collapse, overspilling crater rim, direct blast and eruption column collapse are all ways to generate __________.

pyroclastic flows

If all of the following rocks were to completely melt and reach the same final temperature, which would produce magma with highest viscosity?

rhyolite

____________ in the Aegean Sea underwent an explosive series of eruptions around 1628 bce that buried the Bronze Age city of Akrotiri on Thera to depths of 70 meters.

santorini

In 1964, 12 people were killed during a tsunami at Crescent City, California. All of these fatalities were caused by the _______ wave, which was the highest in the series.

5th

Over _________ of volcanism is associated with the edges of tectonic plates. Question

90%

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).

Iceland

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.

Nevado Del Ruiz, Columbia

In 1959, the water stored behind Hegben Lake Dam in Montana began to slosh violently back and forth in a series of oscillating waves. These seiches were caused by __________________.

a sudden drop of the lake bottom during an earthquake

Slow flowing, more viscous basaltic lava commonly has a rough, blocky texture called ________.

aa

The energy behind the 1902 pyroclastic flow that destroyed St. Pierre came from _________________.

all of the above

Tsunami that reach the shallow water slow down due to __________.

an increase in wavelength

The deadly 1998 tsunami in Papua New Guinea was caused by ________.

an undersea landslide caused by an earthquake

Seafloor spreading generates __________ magma

basaltic

Mineral growth in magmas at the surface with temperatures around 1,000 to 1,200°C occurs in the following way

both correct

The great 1964 Alaska earthquake (M 9.2) set off a tsunami that killed 122 people along the state's sparsely populated coastline. This tsunami also killed 12 people in the state of _________.

california

In August 1986, a gigantic volume of __________ belched forth from Lake Nyos in Cameroon and swept down the adjacent valleys asphyxiating 1,700 people.

carbon dioxide

A mantle hot spot has generated a long-lived plume beneath Yellowstone National Park, and the North American continent is moving __________ above it about 2 to 4 cm/yr.

southwestward

The amount of heat required to raise the temperature of a sample of water is referred to as the ________________heat.

specific heat

What erupts in a geyser?

superheated water and steam

Silicon and oxygen link up to form the silicon-oxygen ______________.

tetrahedron

Spreading centers are an ideal location for volcanism because ______________.

the oceanic plates pull apart causing hot, solid asthenosphere rock to rise and melt because of a decrease in pressure

Adiabatic effects include expansional cooling and compressional warming.

true

At Mt. St. Helens, about 60 people were killed in 1980, primarily by pyroclastic flows and effects related to lateral blast.

true

The plate-tectonic process responsible for volcanoes in the Pacific Northwest region of North America is identical to the cause of the region's great earthquakes—subduction of the Juan de Fuca Plate.

true

The vertical movement of air is large compared to its horizontal motion.

true

Volcanic eruptions can result in the formation of tsunamis.

true

When it comes to volcanic hazards, the key problem is how easily the dissolved gases can escape from the magma.

true

Multiplying 1.25 by the square root of the wavelength results in the velocity of a __________.

tsunami in deep water

_________ eruptions are common first phases in the eruptions of volcanoes as they "clear their throats" before emitting larger eruptions.

vulcanian-type

Most of the people killed by the Mount St. Helens eruption of 1980 __________.

were thought to be in a safe zone

A shield volcano has a great ___________.

width compared to its height