Geophysical Hazards Flashcards
Explain what are plate tectonics
Are what make up the crust and are moved by convection currents.
Explain the process of convection currents
The hot rock rises by being heat up by the earths core. Then, they spread in two directions going sideways and cool down. The coool rock sinks causing the earths crusts to move apart.
Explain what are subduction zones
When an oceanic plates collides with continental plate and it is pushed down since it is less dense.Then, the rock melts which causes rock to rise causing a volcanic eruption.
Define + explain plumes
Outward flow of vocals rock from the center which creates a dragging force that pulls tectonic plates apart.
What are the primary volcanic hazards + explain them
- PYROCLASTIC FLOW—> fast mixture of lava, ash that spreads very rapidly.
- LAVA FLOWS—> molten rock putting and cools as it solidifies (fast-moving)
- PYROCLASTIC surges—> fast clouds of hot ash.
What are the secondary volcanic hazards
A. Lahars—> form of landslides (liquid mudflow), caused by heaving rains and ash
B. Landslides—> rocks separate from mountain sides because of earthquakes/volcanoes.
C. Tsunamis—> euription is in ocean
What is a focus?
The point of stores seismic energy of an earthquake
What is a epicenter
Located above the focus
Types of waves (earthquakes)
- BODY WAVES
A. P-waves —> compressional, faster
B. S waves—> sideways motion - SURFACE WAVES
A. Love ways —> sideways
B. Rayleigh waves
State the human triggers of earthquakes
- Dam constructions —> wight puts pressure on ground
- Mining —>instability of land as minerals are removed
- Fracking—-> drilling which cracks rock.
Sate secondary hazards of earthquakes
- Tsunami
- Landslides
- Liquefaction
Types of mass movements
- soil creeps
- avalanches
- landslides
- rockfalls
- mudflows
Causes of mass movements
- extended rains
- undercutting steep slope
- removal of vegetation
How is the risk management for earthquakes
(PLAN, PREPARE, PRIRITIZE)
- Improve infrastructure (resistant material uses to build houses) + resistant buildings checked by engineers)
- Prepare emergency kits (food water, medicine in houses)
- land zoning maps to identify risky places
- education: emergency drills to prepare individuals
How to measure earthquake freq+ magnitude
- richer scale —> measure seismic energy release (1—10)
- modified mercalli intensity scale—> Roman numerals represent intensity
How to measure volcanic intensity?
- Volcanic explosivity index (VEI)
- based on the amount of material ejected from volcano
Why people live in unsafe area?
- economic factors (poor live there because land is less expensive)
- fertile land for crops
- low education
- tourism —> employment
- nice views
State the indicators of hazard event predictions
- Seisemometers–> they measure earth´s movement
- Tilemeters: measure grounds deformation
- animal behaviours
Indicators of eruptions
- ash deposits in volcanic slopes
- Technology
- GPS monitor
- Satellite
Indicators of mass movements
- Weather forecasts
What are the adaptations of geophysical hazards
- Warning systems
- home preparations
- land-use zoning
- hazard maps
- technology
State and explain pre-event management startegies (landslides)
- artifical structures–> prevention of major lansdlides
- vegetation–> infiltrate water in landslides.
- diverting streams–> to avoid water from rising too much.
- landslides hazard maps
State and explain pre-event mangement for earthquakes
- building on suitable ground–> hard rock
- right building materials
- constructing solid buildings
- hazard maps
pre-event managenemnt startegies for tsunamis
- tsunamis walls–> reflect wave enrgy
- warning systems
- high ground evacuation areas
state the pre-event management for volcanoes
- hazard maps
- constructions (steep rookds to withstand volcanic ash)
- warning systems by monitoring volcanic activity
State post event startegies for geophysical hazards
THE THREE R´S
1. Rescue
2. rehabilitation
3. Reconstruction
