#3 - Important terms and facts from #1

Question 1

What are the patterns of propagation for all seismic waves?

Answer 1

Rayleigh - Retrograde-elliptical
P waves - ‘Push-pull’
S waves - Shear; Perpendicular to wave
Love waves - Slithering of a snake, also perpendicular to wave propagation

Question 2

What is the demographic (population) transition cycle (Ch.1)

Answer 2

Before transition - Birth rates and death rates in equal ratio
During transition - Low death rates and high birth rates causes population to soar
After transition - Low death rates accompanied with low birth rates stabilizes the population

Question 3

What are the main sources of Earth’s internal heat?

Answer 3

• Impact energy - Motion energy of converted into heat energy
• The radioactive atoms decay produces heat
• Frictional energy from differentiation of layers under gravity

Question 4

Isostacy

Answer 4

The Earth’s ability to adjust for any mass stress placed upon it. The asthenosphere bends so the lithosphere can take stress without breaking

Question 5

What is the boundary between low-density
continental rocks and high-density oceanic rocks

Answer 5

1800 m

Question 6

Uniformitarianism

Answer 6

Natural laws are uniform through time and space, present characteristics were true for the past too.

Question 7

Strike and Dip

Answer 7

Strike - The compass bearing direction of the horizontal fault line
Dip - Angle of inclination from horizontal line

Question 8

How much faster do P-waves travel from S-waves and which wave can travel the greatest distance?

Answer 8

1.7 times. Rayleigh waves

Question 9

How is the epicentre distance determined?

Answer 9

The time difference between the P and S waves recorded from several epistemological centres

Question 10

Moment magnitude scale (Seismic Moment M0)

Answer 10

Shear strengthRupture areaDisplacement

Question 11

Mercalli intensity scale

Answer 11

Quantify what people ‘feel’ during an earthquake.

Question 12

Seismic gap method

Answer 12

A tool for predicting sites for future EQs. Faults fail in segments - If recent EQ - Low future probability. If non-recent EQ/failed segment - High future probability.

Question 13

What buildings do you build on a hard bedrock vs soft bedrock base?

Answer 13

Hard - Tall and flexible
Soft - Short and sturdy/strong

Question 14

Pyroclastic Flow

Answer 14

Fast-moving mixtures of hot gases, ash, and volcanic debris that travel downslope. The density and mobility of pyroclastic flows are influenced by factors such as gas content, fragmentation, and the presence of fine ash.

Question 15

Plutonic vs. Volcanic rock

Answer 15

Plutonic - Magma cools slowly and solidifies beneath the surface
Volcanic - Magma erupts quickly and cools on surface.
Both are igneous rocks

Question 16

What is the order of mineral crystallization in magma

Answer 16

OPABQ - Olivine, Pyroxene, Amphibole, Biotite Mica, Quartz

Question 17

The 3 magmas from most peaceful to most explosive eruption

Answer 17

Basaltic (lower H2O content), Andesitic, Rhyolitic (higher H2O content)

Question 18

Decompression melting.

Answer 18

Lowering pressure to melt rock (In relation to volcanic eruptions.)

Question 19

What 3 things cause a rock to melt in a volcano?

Answer 19

1. Decreased or lowering pressure
2. Increasing temperature
3. Raised water content

Question 20

How does the volcano erupt?

Answer 20

1.Melted rock in the form magma in depths of volcano under high pressure.
2. As rocks are molten, the magma expands releasing all the trapped gases (primarily h2o, co2, siO2) due to lower pressure, which act to aggress the volcano to erupt.
3. H2O content impacts how explosive or peaceful the eruption will be.
4. Styles of eruption - Nonexplosive Icelandic and Hawaiian…Explosive Vulcanian and Plinian
5. Rhyolitic magma usually violent due to high H2O and high viscosity

Question 21

The 3 V’s of Volcanology

Answer 21

Viscosity - How easy does the Magma flow
Volatility - How ‘gaseous’, or explosive
Volume - Impacts the intensity of eruption

Question 22

Shield Volcanoes

Answer 22

‘Weakest type’ Low viscosity; Low volatility; Large volume. Great width compared to height

Question 23

Flood Basalt Volcanic

Answer 23

Low viscosity; Low volatility; Very large volume. Largest volcanic events

Question 24

Scoria cones Volcanic

Answer 24

Medium viscosity; Medium volatility; Small volume. Can have Summit Crater with lake

Question 25

Stratovolcanoes

Answer 25

High Viscosity; High Volatiles; Large
Volume. Steep-sided, symmetrical volcanic peaks, Plinian type.

Question 26

Lahars

Answer 26

‘Organic mudflow’. Steam blown up settles on the slopes and condenses. This comes down with heavy rainfall or melting snow in the form of dangerous mudflow full of debris. Also includes ash and debris on volcano slope/surroundings which comes down with rain.

Question 27

Lava Domes Volcanic

Answer 27

High Viscosity; Low Volatiles; Small
Volume. Form when high-viscosity magma at vent of volcano cools quickly into hardened plug.

Question 28

Calderas Volcanic

Answer 28

High Viscosity; High Volatiles; Very Large
Volume. Large (2 to 75 km) volcanic depressions. Formed by roof collapses into partially emptied magma reservoirs

Question 29

Resurgent Caldera