a sudden violent shaking of the ground, typically causing great destruction, as a result of movements within the earth's __crust__ or __volcanic__ action.
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what are volcanoes?
an opening in the Earth's crust through which lava, ash, and gases erupt
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what is a tsunami?
a long, high sea wave caused by an __earthquake__ or other __disturbance__
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what is built up in the crust that causes an earthquake?
continual elastic energy
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what faults are caused at transform boundaries?
strike-slip faults
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what is the richter scale?
a logarithmic measure of the strength of earthquakes
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what are the 2 scales used to measure magnitude?
richter scale and moment magnitude scale (Mw)
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what are the 3 types of seismic waves?
primary, secondary, and surface (love and rayleigh)
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what direction do p waves move?
back and forth in the direction of the path of propagation
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what direction do s waves move?
move back and forth perpendicular to the direction of propagation
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what direction do love waves move?
move parallel to the Earth's surface and perpendicular to the direction of wave propagation
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what direction do rayleigh waves move?
move in an elliptical motion, producing both a vertical and horizontal component of motion in the direction of wave propagation
ash flow, lava flow, pyroclastic flow, lahars, poisonous gas
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what are pyroclastic flows?
explosive columns of volcanic debris, ash and hot gases create fast flows of extremely high temperatures
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what are lahars?
mixture of volcanic material and water that forms a mudflow
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example of ash flow
Eruption at Mount St Helens (1980)
* Collapse of one flank of the volcano that left the north of the volcano devastated
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example of lava flow
Kilauea (2022)
* 111 million cubic meters of lava flow
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pyroclastic flow
Mont Pelee in Martinique (1902)
* Demolished the coastal city of St. Pierre
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lahar
Eruption at Mount St Helens (1980)
* Icy melt water merged with ash, causing a lahar
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what is an effusive eruption?
an eruption wher lava steadily flows out of a flow
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what is an explosive eruption?
build up of pressure that results in an explosion of gas, ash and magma releasing projectile, particulate matter
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what determines magma type?
→ plate boundary type
→ pressure levels
→ temperature
→ minerals present in rock
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what is a hazard?
a potential source of harm
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what is a disaster?
a serious problem that causes wide spread human, material, economic or environmental loss which exceeds the ability of the affected community or society to come using their own resources
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what are the most important factors in determining if a hazard is a disaster?
population density and the built environment of a disaster zone
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what is the Wadati–Benioff zone?
a planar zone of seismicity corresponding with the down-going slab in a subduction zone
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what does the VEI measure?
volume of the erupted pyroclastic material called tephra
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what gases are related to asphyxiation?
carbon monoxide and carbon dioxide
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what layers of the atmosphere can ash enter?
stratosphere and sometimes troposphere
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what chemicals from explosive volcanoes break down ozone?
chlorine and fluoride
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what does sulphur dioxide form when it mixes with water?
sulphuric acid
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what does frozen sulphuric acid become?
sulphate aerosols
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what is radiative forcing?
the difference between the amount of energy from the Sun radiating to Earth and the amount radiated back into space
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how long can a negative radiative forcing last after an eruption?
2-3 years
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what plates, vei and year was mount st helens
north american/juan de fuca (subduction), vei 5, 1980
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how much did mount st helens cost?
$1.1 billion US dollars
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what plates, vei and year was mount pinatubo
eurasian/philippine plate, vei 6, 1991
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how much did mount pinatubo cost?
$250 million in damages
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what climatic phenomena + their impact on a local area do we need to know?
hail, east coast low, droughts, floods, bushfires
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what climatic phenomena do human behaviours contribute to?
droughts, floods, bushfires, landslides
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what causes drought?
El Niño Southern Oscillation (ENSO)
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what is the location example of droughts?
The Macquarie Marshes in Northwestern NSW
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what causes flooding?
la nina, negative indian ocean dipole event
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what is the location example of flooding?
murray-darling basin
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what is the location example of hailstorms?
Northern Rivers district in New South Wales
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what causes an east coast low?
a temperature contrast between the warmer Tasman Sea and cooler continental landmass
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what is the location example of east coast lows?
northern beaches of sydney
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what is the location example of bushfires?
blue mountains national park
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how are volcanoes predicted?
three-dimensional imaging
seismic data
early-warning systems
groundmovement data
analysis of historical data
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what technologies fall under three-dimensional imaging?
tiltmeters
strain meters
GPS
InSAR
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what does InSAR stand for
interferometric synthetic aperture radar
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what technologies fall under seismic data?
seismographs, tomographs
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what technologies fall under gas monitoring?
correlation spectrometer (COSPEC)
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what location examples fall under gas monitoring?
Mount Etna (Italy),
Sakurajima (Japan)
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what location examples fall under historical data?
meep
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how are earthquakes predicted?
ground movement detectors
anomalous animal behaviour
strain meters
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what technologies fall under ground movement detectors:
Studied by 13 people
