chapter 15 volcanoes and earthquakes

Question 1

tsunami

Answer 1

large ocean waves triggered by an earthquake or other natural disturbance of the ocean floor

Question 2

in 2004 the seafloor near ____ in ______ moved upward of 5 m

Answer 2

sumatra

indonesia

Question 3

magma

Answer 3

melted rock between the surface of the crust

Question 4

active vs extinct volcano

Answer 4

active- a volcano that has erupted in the past 10 000 years and could erupt again
extinct- a volcano that has erupted for tens of thousands of years and can never erupt again

Question 5

lava

Answer 5

magma that spills onto the surface of earths crust

Question 6

4 types of volcanoes

Answer 6

1. shield volcanoes
2. stratovolcanoes
3. cinder cones
4. lava domes

Question 7

shield volcanoes

Answer 7

a broad dome shape, with numerous layers of fluid basaltic lava laid down over tens to hundreds of thousands of years

Question 8

magma chamber

Answer 8

the reservoir of magma beneath a volcano

Question 9

volcanic vent

Answer 9

conduit through which magma moves and reaches the surface

Question 10

stratovolcano

Answer 10

a large, potential explosive, cone shaped volcano composed of layers of lava and pyroclasts

Question 11

pyroclast

Answer 11

any fragmented solid material that is ejected from a volcano

Question 12

ash

Answer 12

pulverized rock particles and solidified droplets of lava that form a fine powder

Question 13

lava dome

Answer 13

formed when thick lava cannot easily flow piles up around a volcanic vent and solidifies into a dome shape

Question 14

cinder cone

Answer 14

small cone shaped volcanoes consisting of pyroclast

Question 15

angle of repose

Answer 15

the steepest angle at which loose sediments can settle

Question 16

mafic lava type

Answer 16

silica content 50% or less, low viscosity, darker in color

Question 17

felsic lava type

Answer 17

silica content 70% or more, high viscosity, dominated of iron and silicon, produces volcanic domes

Question 18

pumice

Answer 18

lightweight porous rock with at least 50% air content

Question 19

lapilli

Answer 19

marble to golf ball sized cooled fragments of lava

Question 20

lava bomb

Answer 20

fragments of lava ejected from a volcano that cools and hardens as it is moving through the air

Question 21

volcanic block

Answer 21

fragment of rock that is torn from the volcano’s cone and ejected during an explosive eruption

Question 22

volcanic gases (4)

Answer 22

water vapour, carbon dioxide, sulfur dioxide and hydrogen sulfide

Question 23

joint volcanic landform

Answer 23

crack and weak planes in the rock

Question 24

columnar jointing volcanic landform

Answer 24

a geometric pattern of jointing in volcanic rockfor hexagonal columns when cooled

Question 25

large igneous provinces

Answer 25

accumulations of basaltic lava that covers extensive geographic areas

Question 26

caldera

Answer 26

a large depression that forms when a volcano’s magma chamber empties and collapses

Question 27

effusive eruption vs explosive eruption

Answer 27

effusive- a nonexplosive that produces mostly lava

explosive- sends rock, ash, and volcanic gases high into the troposphere or even into the stratosphere

Question 28

volcanic explosivity index

Answer 28

ranks volcanic eruption magnitude based on the amount of material a volcano ejects during an eruption

Question 29

two biggest threats from volcanoes

Answer 29

lahar- a thick slurry, of mud, ash, and other debris that moves rapidly down the volcanoes flank
pyroclastic flow- blazing cloud (up to 500 degrees), a quick moving (up to 700km/hr) avalanche of gas and ash

Question 30

three basic types of faults

Answer 30

normal fault- tensional force pulls two pieces of earths crust apart
reverse fault- compressional force pushes two blocks together and upward in relation to another block
strike slip fault fault- occurs where one block moves horizontally in relation to another block as a result of a lateral force

Question 31

seismograph

Answer 31

an instrument used to detect, measure, and record ground shaking

Question 32

modified mercalli intensity scale

Answer 32

system used to rank the intensity of shaking during an earthquake

Question 33

liquefaction

Answer 33

the transformation of solid sediment into an unstable slurry by ground shaking