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88 Cards in this Set

  • Front
  • Back

Definition of a Disaster [3 parts!]

Substantial event causing:

1) physical damage,

2) injury or loss of life, and/or

3) a drastic change to the environment

Definition of Atomic Number

The number of protons.

Most common elements in the Earth's Crust [1st - 3rd]

1st. Oxygen

2nd. Silicon

3rd. Aluminium

Most common elements in the Ocean [1st - 3rd]

1st. Oxygen

2nd. Hydrogen

3rd. Chlorine

Most common elements in the Atmosphere [1st - 3rd]

1st. Nitrogen

2nd. Oxygen

3rd. Argon

Most common elements in the Earth's Core [1st - 3rd]

1st. Iron

2nd. Nickel

3rd. Oxygen [?]

Metric Prefixes: M, mega


Metric Prefixes: G, giga


Metric Prefixes: T, tera


Metric Prefixes: μ, micro


Metric Prefixes: n, nano


Metric Prefixes: p, pico


Density definition - and how do you calculate it?

How much Matter is in a Space [mass / volume = ρ]

Compressibility Definition, and what factor does compressing change?

Ability to be squeezed or expanded, so that the mass fills less or more space.

Results in a change in density [mass / volume] of the object, because the volume changes while the mass stays the same.

How does density create Stratification?

Less-dense materials float on top of denser materials. Creates layers or Stratification

Viscosity Definition [what is something like w/ high viscosity?] - and what two factors affect viscosity?

How thick a fluid is– Measure of resistance to flow. [High viscosity – thick, slow flow]

Depends on temperature & chemical structure.

How does Gravity affect Force?

Objects of mass (m) near the earth’s surface are pulled with force: [F = m · g]

Force Definition - and what is its unit of measurement?

A force pushes or pulls.

Its unit is the Newton (N).

Work Definition

The force (F) that pushes an object, times the distance (d) the object moves.

Potential Energy (PE) Definition

The work needed to raise an object of mass (m) a distance (z) against the pull of gravity (g) (e.g. a boulder on a cliff edge has a lot of potential energy)

Kinetic Energy (KE) Definition

A moving object possesses kinetic energy [KE = 0.5· m· v^2]

Potential energy can transform into Kinetic energy?

Sensible Heat Definition

Heat energy we can sense or feel –When we measure Temperature we are measuring sensible heat

Latent Heat definition

A kind of potential energy, consisting of “Hidden” heat energy in chemical bonds between atoms

How is Sensible Heat affected during melting or boiling?

Sensible heat “stored” as latent heat - heat is taken from the surroundings

How is Latent Heat affected during condensing or freezing?

Latent heat released as sensible heat - heat is transferred/released to the surroundings

What scales are used when charting Order-of-Magnitude?

Logarithmic Scale, which increases by powers of 10.

What are the Earth's three main external energy sources? [e.g. not internally caused by decaying radioactive elements]

1. Solar Irradiation [Largest]

2. Tidal Energy

3. Low Impact Energy (from meteorites etc.)

Describe the Rock Cycle

Heat and pressure (metamorphism) transforms sedimentary rocks into metamorphic rocks

Risk definiton, and what is one way of writing it as a formula?

Probability that any given hazardous event might occur, causing potential loss.

Can be written as: Hazard x Vulnerability = Risk

Return Period (RP) Definition

Average number of years between disaster events of the same magnitude (M)

Carrying Capacity Definition

The population that can be sustainably supported within a given domain (e.g., Earth)

How has human population growth changed in recent years?

Growth used to be exponential (1.1%/yr), but is now linear (1 billion more people every 13 years)

What is the difference between the crust and the mantle, and which consists of the Earth's Tectonic plate?

Crust is the top cold part, whereas the Mantle is the middle warm part. Tectonic plates [the Lithosphere] are made of SOLID crust and SOLID upper part of mantle.

Lithosphere Definition

The solid, brittle outer rigid shell of the Earth that lies above the asthenosphere [crust & uppermost mantle]

Asthenosphere Definition

The solid, ductile layer of the Earth below the Lithosphere where rocks deform readily and flow slowly. [mantle]

3 factors that control Plate Tectonics

1. Composition

2. Heat

3. Gravity

3 types of Deformation

1. Elastic - springs back (reversible)

2. Ductile - plastic flow (permanent)

3. Brittle - breaks (permanent)

Factors that affect Deformation

Temperature, pressure, and the speed/duration of deformation

Differences between Continental and Oceanic Crust

[what they are made of, thickness, and density]

Continental Crust is made of Granite, is thick and relatively less dense, Oceanic crust is made of Basalt, is thin and more dense

Basal Drag definition [Plate Tectonics]

Friction between the rigid Lithosphere and the more ductile asthenosphere drags the plate along

Slab Pull definition [Plate Tectonics]

Cold descending plate is denser than hot mantle, gravity pulls it down.

Ridge Pull definition [Plate Tectonics]

Heating at the rift raises the ridge crest, gravity pulls the elevated plates down and apart.

What are the typical rates of convergence?

Rates of convergence are approximately two to eight centimetres per year

What are the three major plate boundaries?

1. Convergent

2. Divergent

3. Transform

What is the Earthquake fault and what forces are occurring in a Convergent plate boundary?

It is a Thrust/Reverse fault, with strong Compression forces [plates moving towards each other]

What is the Earthquake fault and what forces are occurring in a Divergent plate boundary?

It is a Normal fault, with weak Tension forces [plates moving away from each other]

What is the Earthquake fault and what forces are occurring in a Transform plate boundary?

It is a Strike-Slip fault, with mid-strength Shear forces [plates moving against each other]

Do all earthquakes occur in the Lithosphere or the Asthenosphere, and why?

The Lithosphere, the Asthenosphere is too ductile.

What are the 2 sub-types of Divergent plate boundaries, and what is formed in both of them?

Oceanic <---> Oceanic plate spreading

Continental <---> Continental plate spreading

New Oceanic lithosphere is created

Why is it always the oceanic plate that is subducted?

Continental crust is much less dense (‘lower density’ - more buoyant) than mantle rock

If two oceanic plates converge (convergent plate boundary), which one subjects and why?

The older plate subjects, as it has had more time to cool, and is therefore more dense

What are the three Earthquake locations in subduction zones at convergent plate boundaries?

1) On the plate Interface [where Megathrust quakes are formed]

2) In the overriding plate

3) Within the down-going Lithosphere plate

Elastic Rebound definition

As rocks on opposite sides of a convergent fault are subjected to force and shift, they gradually uplift and compress until their elastic limit is exceeded. At that time, the brittle crust breaks at the hypocentre, causing very rapid subsidence and extension, and the rocks snap back to their original undeformed shape.

What are the two sub-types of convergent plate boundaries, and which has the greater earthquakes?

A). Subduction

Oceanic --\ <--- Oceanic plates

Continental plates ---> /-- Oceanic

B). Collision [V. large earthquakes]

Continental ---><--- Continental Plates

If two continental plates converge (convergent plate boundary), which one subjects and why?

Neither, as they fuse together [Collision], creating major deformation

Is any lithosphere created or destroyed at Transform plate boundaries?

There's no creation or destruction of lithosphere

Which plate boundary has the most frequent earthquakes?

Divergent (but they are generally weaker earthquakes)

Difference between Hypocentre and Epicentre

Epicentre is the ground-level point above the earthquakes actual point of origin, the Hypocentre

How fast are P-waves, how do the particles move, what do the waves travel through, and how destructive are they?

They are the fastest waves, the particles move back and forth with the direction of the wave [compressional], and the waves can travel through solid or fluid. The waves are not very destructive.

How fast are S-waves, how do the particles move, what do the waves travel through and how destructive are they?

They are the second fastest waves (behind P-waves), the particles bend perpendicular to the wave motion [transverse], and the waves can only travel through solids. Near-horizontal ground motion is very destructive.

How fast are Rayleigh waves, how do the particles move, what do the waves travel through and how destructive are they?

They are Surface waves, which makes them move relatively slowly, the particles move in a vertical circular motion. These rolling motions are the most destructive.

How fast are Love waves, how do the particles move, what do the waves travel through and how destructive are they?

They are Surface waves, which makes them move relatively slowly, the particles move side-to-side perpendicular to the wave. Surface waves are generally very destructive.

Define Earthquake Magnitude

Quantitative measure of the amount of shaking or ground motion (also area affected, duration) - related to the amount of energy released.

Why can't S-waves propagate through fluids but P-waves can?

Transverse waves (such as S-waves) need a medium rigid enough to propagate, and liquids do not have a high shear strength to allow the wave to pass through.

Compressional waves (Such as P-waves) do not require a high shear strength.

What does the Local Richter Magnitude (Ml) measure?

Maximum ground motion (surface wave amplitude)

What two things do Body Wave (Mb) and Surface Wave (Ms) Scales measure - and what is one problem?

These scales measure amplitude [Frequency and Ground Motion] - They are not accurate for large or distant earthquakes, as the larger the earthquake is, the more energy it generates at very low frequencies.

What scale do Geologists now use to measure earthquakes?

The Moment Magnitude scale

What does the Moment Magnitude Scale measure, and what 3 physical properties does it look at?

Measures strain energy along rupture surface (energy released) based on:

1). area of the fault

2). distance that the fault slipped

3). rigidity or stiffness of the rock (shear strength)

In the Moment Magnitude Scale, the amount of Ground Motion increases logarithmically (by powers of 10), but how much does the amount of energy released increase for each factor of 10 increase in Magnitude?

Increases by 10^1.5 (approx. 32 times)

Can the Moment Magnitude Scale have Magnitudes that are negative, and can it have Magnitudes that go above 10?

Magnitudes can be negative (v.small earthquakes), but a M10 quake is larger than is possible on Earth

Earthquake Intensity definition - and what do we use to measure it?

A qualitative estimate of how ground motion affects population and structures. How the shaking is perceived, combined with the damage resulting from vibrations [Descriptive, not Quantitative]

We use the Modified Mercali Scale to measure earthquake intensity

Are buildings most damaged by horizontal or vertical shaking?

Horizontal shaking

What Ground Properties can increase our perception of earthquake intensity, and why?

Water saturated sediment, because the soft ground 'filters' earthquake frequencies, affects how long the shaking continues, causes larger amplitudes and slower vibrations, and influences the stability of structure's foundations

What [2] descriptions of buildings make them best suited to surviving earthquakes, and what [3] materials should be used when building them?

Flexible and Strong, and preferably made of Wood, steel, and/or reinforced concrete

If the building is tall, then it can be tuned to avoid resonance disasters

Resonance Disasters definition

When 'forcing' earthquake vibrations are tuned to one of the primary resonant frequencies of a structure, it can cause dramatic shaking

Do taller or shorter buildings have lower natural resonant frequencies?

Taller Buildings

Liquefaction definition

Shaking causes soft, wet, unconsolidated soils to 'liquify' (contact forces decreasing between the soil grains) - loosening its cohesion and causing it to flow

What is the name of the area parallel to the Convergent plate boundary of the Juan De Fuca plate, where the hypocentre of a Megathrust earthquake can occur?

Megathrust locked zone

What evidence would you look for to see when previous Megathrust earthquakes had occurred on a convergent boundary?

Elastic Bending and Compression (gradual uplift of the plate and shortening --><--), can also look for evidence of past tsunamis (e.g. thick sand layers) and turbidites (underwater landslides). Also written/oral history

Return periods for M9 and M8.3 earthquakes in the Cascadian region.

M9: roughly 500 years

M8.3 roughly 230 years

Which hypocentre location in a subduction zone would be the worst for Vancouver?

A shallow crustal quake occurring on the plate Interface

What are earthquake Precursors, and are they useful in predicting earthquakes?

Anomalous observations that precede an earthquake - they are not useful as they are neither reliable nor repeatable.

Seismic Gap definition

A segment of an active fault known to produce significant earthquakes which has become locked - strain accumulates but no ruptures occur. Indicates a zone with increased large earthquake likelihood

Geodynamic research into crust deformation and computer modelling may enhance what?

Earthquake forecasting (< 10 years)

How many seismograph stations do you need to locate an earthquake's hypocentre?

three, that can triangulate the delay in arrival time between P and S waves

How are Tsunamis created?

The fault rupturing the seafloor and lifting/dropping the entire water column situated above the fault [NOT caused by the earthquake waves]

Do Earthquakes often trigger volcanic activity nearby?

No, only on very rare occasions.

What are turbidites, and what generally causes them?

Underwater landslides, caused by Megathrust earthquakes