Geo 004

4 A's of mitigation

Avoid, accept, anticipate, alter

Which describes the lithosphere?

Behaves rigidly and is brittle, "floats" on top of the asthenosphere, is solid, consists of the crust and upper mantle, NOT where earthquakes occur

Magnitude

Bigger the earthquake, the more energy emitted and more rare

The Earth's innermost layer is known as the core when considering ___ properties, but is broken into 2 layers, outer core and inner core, when discussing ___ properties.

Chemical, physical

Dip slip: Reverse fault

Compressional setting, hanging wall moves up

Volcanoes are formed at ___ .

Divergent and convergent plate boundaries

Geometrical spreading

Energy has to be spread over a large area as the distance from the source increases (think of ripples)

Dip slip: Normal fault

Extensional setting, hanging wall moves down

Normal faulting occurs when the hanging wall moves upward relative to the footwall

False

Shield volcanoes are steep-sided, symmetrical volcanic peaks built of alternating layers of pyroclastic debris capped by high-viscosity andesitic to rhyolitic lava flows.

False

Radical component

Forward and backward

Why does amplitude vary from location to location? Why do amplitudes vary from earthquake to earthquake?

Geometrical spreading, attenuation, rock type, site effects, earthquake magnitude

Super volcano

High viscosity, high volatility, very large volume

Lava dome

High viscosity, low volatility, small volume

Which characteristics describe a transform plate boundary?

Horizontal sliding plate motions, occurrence of earthquakes, and strike-slip faulting

The ___ is where an earthquake starts and the ___ is a surface point on map directly above the hypocenter.

Hypocenter, epicenter

The most peaceful eruptions are

Icelandic type eruptions

Internal heat energy

Impact of asteroids and comets, decay of radioactive isotopes, gravitational energy, differentiation into layers

Attenuation

Loss of energy with distance due to scattering and friction 1. Friction between mineral grains dissipates energy and reduces amplitude 2. The longer the wave travels, the more energy is lost (doesn't happen in cold areas) 3. Different rocks/regions have different friction properties- variable attenuation

shield volcano

Low viscosity, low volatility, large volume

After lava cools, atoms in iron-bearing minerals on the seafloor become ___ . This evidence of ___ is just one dataset supporting the theory of plate tectonics.

Magnetized in the direction of the Earth's magnetic field at that time and place, seafloor spreading

Flood basalts

Massive volume of magma, mass extinctions, low viscosity, low volatility, very large volume

Stratovolcano

Med/high viscosity, med/high volatility, large volume

Cinder (scoria) cone

Medium viscosity, medium volatility, small volume

Mechanical Layers

Physical properties, material strength

convergent plate boundary

Plates colliding (subduction zone) anything dense goes down

P waves

Primary seismic waves, Sound waves, side to side motion

What type of motion is associated with divergent plate?

Pull apart

What characteristics describe a divergent plate boundary?

Pulling apart plate motions, occurrence of earthquakes, and normal faulting

What type of motion is associated with convergent plate boundaries?

Push together

What characteristics describe a convergent plate boundary?

Pushing together plate motions, occurance of earthquakes, and reverse faulting

The primary cause(s) of death from explosive volcanic eruptions is (are) ___.

Pyroclastic flow

___ faults are commonly found at areas of plate convergence where subduction or continental collision occurs.

Reverse

Surface waves: rayleigh wave

Rolling motion, particle motion is circular

Seismic waves

Ruptures releases energy as seismic waves that pass through the earth

S waves

Secondary, up and down motion

Rock type

Sediment or soil have large amplitudes and rock have smaller amplitudes Sediment= soft, ground easily moves Bedrock= hard, ground does not easily move

Site effects

Sediment sites amplify seismic waves (liquefaction)

Several geologic phenomena are considered precursors of an impending volcanic eruption. These include ___, ground deformation, and ___.

Seismic waves, the release of gases

Evidence for plate tectonics

Shape of the continents, rocks of mountain belts, fossils, earthquake locations, volcano locations and hot spot volcanism, seafloor magnetization and age

strike-slip fault

Shearing setting, moves horizontally

Tangential component

Side to side

Volume

Size of magma chamber, more magma= more erupted material

What type of motion is associated with transform plate boundaries?

Slide past

Chemical Layers

Sorted by density, heaviest elements near center

Map design elements

Title, numeric scale, north arrow, legend, graphical scale

A majority of earthquakes occur on or near plate boundaries.

True

Hot spots have active volcanoes above them on the Earth's surface and moving plates carry the volcanoes away from their hot-spot source.

True

Strike-slip (transform) faults usually link spreading centers or connect spreading centers with subduction zones.

True

The movements of the lithospheric plates are directly responsible for the vast majority of the earthquakes, volcanic eruptions, ans mountains on Earth.

True

The rates of plate movements are comparable to those of human fingernail growth

True

The types of rock or sediment on which a structure's foundation sits are of paramount importance with respect to whether the structure will be damaged by shaking from an earthquake

True

Volcanoes tend to occur mostly along plate boundaries.

True

In addition to lava flows, volcanic processes can cause

Tsunamis, debris avalanches, lahars

Vertical component

Up and down

3 V's of volcanic hazard

Viscosity, volatiles, volume

The three Vs of volcanology are ___ .

Viscosity, volatiles, volume

Epicenter

Where seismic waves rupture, location on the surface directly above the hypocenter

Hypocenter

Where seismic waves start, location in earth where earthquakes begins

Surface waves: love waves

Zig zag motion, increase in depth there's a decrease in motion, slower than p and s waves

Slow flowing, more viscous basaltic lava commonly has a rough, blocky texture called

a'a

A caldera collapse occurs

after the magma chamber is mostly empty

Types of plate boundaries

convergent, transform, divergent

When oceanic lithosphere collides with another plate, the ___ in the process of subduction.

older, colder plate turns downward beneath the younger, warmer plate

divergent plate boundary

plates pull apart

As radioactive atoms decay, energy is

released

Viscosity

resistance to flow, higher it is the more explosive

transform plate boundary

sliding past each other