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Geology test 4
final geology test
50
Geology
Undergraduate 1
12/02/2010

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Cards

Term
A ________ is is a type of mudflow or debris flow composed of pyroclastic material, rocky debris, and water.
Definition
lahar
Term
___________ will change the characteristics of floods especially in smaller streams
Definition
urbanization
Term
A ___________ is one of a number of channel types and has a channel that consists of a network of small channels separated by small and often temporary islands called braid bars
Definition
braided river channel
Term
[image]
Definition
Point bars and Cut banks
Term
When there is intense rainfall there is a short duration of an _____________.
Definition
upstream flood
Term
A _______________ is a flood that has a 10% chance to occur every year.
Definition
ten year flood
Term
ultimate base level is also known as ______________.
Definition
sea level
Term
Bed load is __________ of the amount of sediments being transported downriver.
Definition
not a prominent portion
Term
With the same amount of discharge, a short narrow channel will have _______________ than a wide deep channel.
Definition
a higher water velocity
Term
a downstream flood covers ___________.
Definition
a huge area
Term
an upstream flood is quick and covers ________________.
Definition
a short small area
Term
The _______________ is the region drained by a single river or river system.
Definition
drainage basin
Term
The 1980 eruption of Mt St Helens did not produce _______________.
Definition
a live lava flow
Term
Ash plumes are ____________.
Definition
dangerous
Term
The 1993 Mississippi river flood was affected greatly by the st Louis flood walls that produced ________________.
Definition
a bottleneck effect
Term
The suspended load in a river is mostly _______________.
Definition
silt and clay
Term
The dam-like effect of the 1993 Mississippi river flood caused __________________.
Definition
the flooding of 4 streams
Term
The portion of rainfall that flows off land and directly into the river is referred to as ____________.
Definition
runoff
Term
A stream channel has ________________.
Definition
constant width and depth
Term
We accommodate additional discharge by _____________.
Definition
increasing velocity
Term
The total load or volume of sediment in a river is known as ______________.
Definition
its capacity
Term
A ___________ is a steep conical hill of volcanic fragments that accumulate around and downwind from a volcanic vent.
Definition
cinder cone volcano
Term
hawaiin islands formed as a result of __________________.
Definition
being on a hot spot
Term
An _____________ is avalanche of volcanic ash, generally a highly heated mixture of volcanic gases and ash, traveling down the flanks of a volcano or along the surface of the ground.
Definition
ash flow
Term
when mt st helens erupted, what was the first event?
Definition
landslide
Term
a lahar is _________________.
Definition
a volcanic mudflow
Term
____________ plays a big influence in the nature of a volcanic eruption.
Definition
viscosity
Term
a shield volcano is __________ in composition.
Definition
basaltic
Term
composite volcanoes are formed from ______________.
Definition
lava flow and pyroclasic debris
Term
A ___________ is one of the last thing that can kill you in a volcanic eruption.
Definition
lava flow
Term
There are many things that can kill you during an eruption ________________ lava flow.
Definition
before there is ever
Term
___________ was a 1991 eruption that killed over 20 scientists and journalists.
Definition
Mt Henson
Term
Why is topographic monitoring useful in forecasting volcanoes?
Definition
The mountain may swell which can be picked up by the monitoring.
Term
Why is it important to know volcanic frequency?
Definition
It tells you how often the volcano erupts.
Term
Why are seismographs useful?
Definition
they can detect lava moving in the subsurface that create a lot of small earthquakes
Term
____________ was a very large eruption with few deaths because the people there were very prepared for that eruption.
Definition
Mt Pinatubo in the Philippines
Term
At _________ something was triggered and a sudden release of about 1.6 million tonnes of CO2 this cloud rose at nearly 62 miles per hour.
Definition
Lake Nyos
Term
A ___________ when snow and glaciers are melted by lava or a pyroclastic flow during an eruption.
Definition
a lahar is formed
Term
Why is ash fall bad?
Definition
Aside from the dangers of breathing it in, the ash can collapse a building.
Term
How did Iceland stop a lava flow?
Definition
They sprayed the flow with 6 million cubic meters of water to cool the lava enough so it would solidify.
Term
What is the difference between a crater and caldera?
Definition
During certain types of climactic eruptions, the volcano's magma chamber may empty enough for an area above it to subside, forming what may appear to be a crater but is actually known as a caldera.
Term
Continental volcanoes are usually in _____________.
Definition
subduction zones
Term
Why are most active volcanoes associated with plate tectonics?
Definition
It has to do with sinking and spreading of quakes that produce magma.
Term
The viscosity of the magma is controlled by _____________________.
Definition
the temperature and the amount of silica
Term
How is the shape of a shield volcano is a function of the viscosity of it.
Definition
The magma is very very viscous and slow moving so the sides of the volcano have a very large slope at a small angle.
Term
know what composite volcanoes are composed of __________________.
Definition
alternating layers of lava and rock fragments
Term
Mid oceanic ridge volcanism produces what kind of volcanic rock?
Definition
Basalt
Term
Ash flow is also referred to as _______________.
Definition
a glowing avalanche
Term
A _________ is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption
Definition
Caldera
Term
A __________ is a circular depression in the ground caused by volcanic activity.
Definition
volcanic crater
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