Volcanic Eruptions - VOLCANIC HAZARDS AND NOTABLE DISASTERS

Question 1

The way in which humans respond to potential volcanic threats depends on several factors, in particular, the ______ and the _____

Answer 1

frequency at which eruption occur ; availability of habitable living space

Question 2

some of the primary hazards near a volcano

Answer 2

violent eruption and lava flow

Question 3

secondary hazards of volcanoes that can reach considerable distances

Answer 3

mudflow, lahar, suspension of volcanic ash and toxic gases into the atmosphere, tsunamis and landslides

Question 4

occurs whenever magma reaches the surface and begins to move across the landscape

Answer 4

lava flows

Question 5

how fast and how far a lava flow will travel is largely determined by

Answer 5

slope of land surface;
volume of lava;
viscosity of lava

Question 6

t or f: lava flows are very common in hawaii

Answer 6

T

Question 7

t or f: gas poor magmas can generate large steam explosions should the magma suddenly come in contact with a significant volume of groundwater or seawater

Answer 7

T

Question 8

what are the most common hazards from explosive eruptions?

Answer 8

pyroclastic material and hot gases

Question 9

the ____ during an explosive eruption pulverizes rocks making up the volcano into smaller fragments, hurling them upward and at great speed along with superheated gases and blobs of lava

Answer 9

shock wave

Question 10

example of a lateral eruption

Answer 10

Mt. St. Helens, 1980

Question 11

a volcanic eruption which is directed laterally from a volcano rather than upwards from the summit

Answer 11

lateral eruption or lateral blast

Question 12

pyroclastic flow is a dry avalanche consisting of ______, _____, and ____, all rushing down the side of a volcano at great speed

Answer 12

hot rock fragments, ash, and superheated gas

Question 13

a typical pyroclastic flow consist of two parts:

Answer 13

a tumbling mass of large rocks;

overlain by

a turbulent cloud of finer material

Question 14

t or f: pyroclastic flow can form during explosive and nonexplosive eruptions

Answer 14

T

Question 15

t or f: pyroclastic flow are almost always associated with SiO2 poor magma

Answer 15

F (SiO2 rich)

Question 16

how far was Mt. Peele from the City of Pierre

Answer 16

7km

Question 17

two most famous examples of pyroclastic flow

Answer 17

Mt. Vesuvius, Italy (79 AD)
Mt. Peele, Martinique (1902)

Question 18

jagged rock and glass fragment less than 2mm in diameter

Answer 18

volcanic ash

Question 19

volcanic ash are transported by ____ at considerable distances prior to disposition

Answer 19

wind

Question 20

hazardous effects of volcanic asg

Answer 20

a.) respiratory conditions
b.) destroy crops
c.) contaminate surface water
d.) increasing severity of flooding
e.) damage to mechanical property
f.) trigger global cooling

Question 21

volcanic ash can damage mechanical and electrical equipment because of its

Answer 21

abrasive property

Question 22

Mt. Pinatubo temperature drop by:

Answer 22

0.25 degrees celsius

Question 23

Mt. Tambora temperature drop by:

Answer 23

3 degrees celsius

Question 24

when was the year without summer

Answer 24

mount tambora eruption (1815)

Question 25

two types of mass wasting on volcanoes

Answer 25

volcanic landslide and volcanic mudflows

Question 26

also called as debris avalanche

Answer 26

volcanic landslide

Question 27

occurs whenever a steep flanks of volcano become unstable and results in rapid downslope movement

Answer 27

volcanic landlside

Question 28

volcanic landslide is often triggered by

Answer 28

earthquake and heavy rains

Question 29

______ and _____ within a volcano can breakdown _____ rocks into much weaker _____, thereby making slope more prone to volcanic landslide

Answer 29

corrosive gases; groundwater; feldspar-rich; clay minerals

Question 30

also called a lahar or debris flow

Answer 30

volcanic mudflows

Question 31

is an indonesian term, and is a mixture of ash, rock, and considerable amounts of water

Answer 31

lahar

Question 32

ash and rock in volcanic mudflows may comprise _____ by weight, and may resemble a river of wet concrete

Answer 32

60 to 90%

Question 33

speed of volcanic mudflows

Answer 33

35-60 km/hr

Question 34

t or f: volcanic mudflows are more destructive than ordinary river floods

Answer 34

T

Question 35

volcanic gas is mainly composed of:

Answer 35

water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)

Question 36

H2O, CO2, and SO2 together account for ____ of all volcanic gases

Answer 36

over 95%

Question 37

volcanic gas cloud is hazardous to humans simply because it contains _____

Answer 37

no free oxygen (O2)

Question 38

forms when volcanoes explode violently in an oceanic setting and may subsequently strike coastal communities far from the volcanoes itself

Answer 38

tsunamis

Question 39

t or f: volcanic landslides may also generate large tsunamis

Answer 39

T

Question 40

what was the major secondary hazard during the Mt. Tambora volcanic eruption in 1815

Answer 40

volcanic ash and short-term climate change (starvation from crop failure)

Question 41

what was the major secondary hazard during the Nevado del Ruiz, Colombia eruption in 1985?

Answer 41

mudflow

Question 42

what was the major secondary hazard during the lake nyos, cameroon eruption in 1986

Answer 42

gas asphyxiation (CO2)