Natural Disasters Exam 2

What type of magma erupts from Hawaiian volcanoes?

basaltic

_________ magma is the most viscous(sticky); therefore, it produces ________ eruptions

rhyolitic; violent

Which type of magma has the highest silica content

rhyolitic

Name three geologic events associated with the eruption of Mount St. Helens

earthquake triggered a landslide; pyroclastic flow; lahar

How does a caldera form

collapse of the volcano into the magma chamber after eruption

It would be unwise to build your house along the ________ of a stream because erosion is the dominant force there?

cut bank

What does the dissolved load in streams consist of

dissolved ions (minerals)

What happens to the discharge of the Colorado as it reaches its mouth (Gulf of California) Why?

discharge decreases to near zero (no flow) because of all the big cities that use Colorado River water (las Vegas, LA)

How does urbanization affect lag time

shortens the lag time (time between rainfall and flooding

a river system consists of three zones. which of the following characteristic of zone 3

broad floodplain

flash flooding

formation of a delta

erosion

formation of a delta

what two horizons make up the topsoil

O & A

it takes 500 years for 2 _______ of soil to form. From this we see that time greatly affects soil development

inches

name two features associated with karst topography

sink holes, caves, disapperaing streams

how have humans contributed to subsidence along the Mississippi Delta? list three ways

restricting sedimentation by building dams and levees

withdrawl of oil and groundwater

canal building which allows salt water to invade and kill plants

a soil _________ is an arrangement of soils from youngest to oldest based on their relative development

chronosequence

what happens when driving forces overcome resisting forces

slope failure! (a landslide)

wildfires are a frequent occurrence in California. which mass wasting process typically follows the first rainstorm after a fire

debris flow

what causes soil to creep

expansion and contraction of the ground due to freeze/thaw cycles, causing soil particles to move downslope

Rocks do not weather uniformly which causes overhanging ledges of resistant rocks over eroded ones. What type of mass wasting event would this likely cause

rock fall

list some factors responsible for causing the large Gros Ventre landslide outside of Jackson, WY

rain and snowmelt saturated a sandstone layer that rested on top of an impermeable (and slick when wet) layer of shale (clay)

when did lake bonneville reach its highest elevation

17,000 years ago

what caused lake bonneville level to drop precipitously over the course of a few weeks/months from its highest level

a catastrophic flood at red rock pass in southern Idaho

what type of volcano typically occurs in clusters and has a life span of several years

cinder cone

what type of mass wasting event occurs as blocks of rock slide down a slope

rock slide

what forms when a river abandons its meander

oxbow lake

what are the three main types of magma

basaltic, andesitic, rhyolitic

what type of magma has the highest silica content

rhyolite

what type of magma is more viscous

rhyolite

rhyoltic magma is also called _____. it has high ________ content and therefore is _______ in colr.

felsic; sillica; light

violent volcanic eruptions are characterized by magma with high viscosity and lots of dissolved gasses

true

what type of volcano is hawaiian volcanoes like mauna Loa

shield volcano

what type of colcano is cascade volcanoes, like mt. saint helens

stratovolcano

what type of volcanoes are in craters of the moon national monument in idaho

cinder cone

what type of volcano was the major eruptions at Yellowstone national park

continental caldera

The people of Pompeii died as a result of a _____ that emanated from a _____ called Mt. Vesuvius

pyroclastic flow; stratovolcano

which of the following are NOT a natural service function of volcanoes and their magma sources?

clean drinking water

rich, fertile soil

geothermal energy

recreational areas, such as some ski resorts

clean drinking water

what evidence found in Pompeii supports the idea that the eruption of mt. vesuvius in 79AD erupted suddenly and was unexpected

bread was baking in the oven at the time of the eruption

the poses of the people that died in the eruption are known because

the bodies decayed and left behind voids that are filled with plaster

the cause of the volcanoes in the vicinity of Naples is _______

the subducting African plate

earthquakes precede eruptions. these quakes are caused by magma fracturing rocks. in fact, minor quakes at Vesuvius ______

every week

besides earthquake activity, how do scientists monitor mt. vesuvius

collect CO2 gas samples from a fumarole inside the crater

_____________ witnessed the eruption of mt vesuvius and described it as a ___________

plint the younger; pine tree

the size of the pumice is proportional to the ___________

height of the ash column

one third of the victims died from

collapsed roofs loaded with pumice

the pumice was followed by a

pyroclastic flow

campi flegrei sits on top of a giant

cldera

what is the difference between a delta and an alluvial fan

a delta forms in water, such as an ocean or lake, wheras an alluvial fan forms on land

where is the mouth of the Colorado river

in the gulf of california

what is the purpose of a levee, both natural and man-made

to minimize the risk of flooding

which of the following statements about floodplains is NOT true

floodplains have low risk of flooding

which zone of a river is called the zone of production because is located in the upper reaches where there is steep topography and sediment production

zone 1

the angle of sediments at rest is called the

angle of repose

which of the following mass wasting events involves the movement of rock or regality under the direct influence of gravity

debris flow

rock slide

rock fall

all of the above

all of the above

why do debris flows commonly occur following a wildfire

wildfires bake the ground causing an impermeable layer to form

which type of mass wasting event results in curved tree trunks and learning fence posts

creep

which type of natural hazard will likely NOT trigger a landslide

tornado

Which of the following DOES NOT influence soul development

longitude

climate

parent material

time

topography

longitude

how long does it take for a well developed soil to form

40,000 to several hundred thousand years

how is karst topography related to subsidence

dissolution of limestone can cause sinkholes to form

humans can actually cause subsidence to occur. This is the case in the examples of New Orleans and Vencie

true

there are thousands of copper mines in the Gulf of Mexico

false

in order to build a 20-ft high wall, how deep should the foundation be

6-8ft

what is the problem with building the wall on clay-rich soil

it swells like a sponge then shrinks again, cracking foundations

what are the problems associated with potentially building a border wall in high sulfate soil

sulfate breaks down metal and concrete

there is history of earthquakes along the US-Mexico border

true

what delinateates the Texas-Mexico border

the rio grande river

why is the pacific ring of fire so firey

its a subduction zone

what are c-shaoed lakes called

oxbow lakes

how do urban areas affect lag time and the peak flood?

shorter lag time and larger peak flood

mass wasting refers to the downslope movement of rock, regolith, and soil under the direct influence of _______

does not require a transporting agent (water, wind or ice); _____ does

gravitiy, erosion

what type of mass wasting event involving large rocks, soil and water moving downslope commonly occurs after a wildfire?

debris flow

fire can bake the ground, causing a water-repellent layer that slows infiltration= increased surface runoff

what kind of mass wasting event causes talus slopes to form at the base of steep cliffs

rock falls

what type of mass wasting event involves bedrock sliding down a slope

rockslide

movement of a mass of rock or unconsolidated material along a curved surface is a _______

slump

what causes Soil Creep to occur

freeze-thaw causing expansions and contraction of particles = slow movement downslope

When did the Thistle landslide occur? what caused it

Heavy rains and snow melt in 1982/83

soil is solid earth material that has been altered by physical, chemical and organic processes such that it ______ _____

supports life

What are typical components in soil

air, water, organic matter and mineral matter(from weathered rock)

no soil development because of very ______ ______

steep slpoe

_____________ soil developed on stream-deposited sediment

transported

__________ soil is developed on bedrock

residual

____________ soil on steep slope because of erosion

thinner

vertical differences are called_________ zones or layers of soil

horizons

O horizon

organic matter

A horizon

humus and mineral matter

together the O and A horizons make up the _________

topsoil

e horizon

little organic matter

e horizon zone of ________ and leaching

eluviation

b horzion

zone of accumulation

c horizon

partially altered parent material

what factor is most important in determining whether a soils is weakly, moderately or well developed

time

Soil __________________: soils arranged from youngest to oldest based on their relative development

chronosequence

_________ is one of the biggest causes of erosion

rain

what factors contributed to the dust bowl of the 1930s

drought

wind

hotter than normal temp

poor farming practices

collapesd ____ _____ in hawaii

lava tubes

kentucky has a landscape as an excellent example of ______ topography as evidenced by the sinkholes

karst

carbon dioxide dissolved in water forms carbonic acid which decomposes ___________ rocks

limestone

___________ commonly form in flordia, because the whole state is underlain by ___________

sinkholes, limestone

buildings slump together as the permafrost beneath them thaws in Yukon, Canada. What is this know as

thermokarst

what is causing land subsidence in the San Joaquin Valley in California

groundwater withdrawal