geo, hazards

Hazard

An event with the capacity to cause harm to people, property

Natural disaster

An extreme natural event that has affected many people (10 or more dead 100 or more affected)

Vulnerability

The ability of a person or group to anticipate, cope with and recover from the impacts of a hazard.

Factors affecting capacity to cope

Level of development, commitment to prediction, preparedness and response

Oceanic plate

Plate, part of earths crust and under ocean, can subduct, thinner and denser

Continental plate

Plate part of earths crust that forms continents, thicker, less dense and cannot subduct

Name 4 plate margins

Conservative, constructive, destructive(oceanic-continental), destructive(continental-continental)

Causes of earthquake and where they form

Occurs at conservative or destructive plate or constructive plate

Plates don’t rub smoothly there is lots of friction

Pressure builds up as elastic strain until it exceeds friction

Causes plates to jolt past each other releasing seismic waves from the focus.

Hazards associated with earthquakes and explain

Soil liquefaction and tsunamis- destructive plate boundary plate displaces water, energy ripples through water and wave becomes large in shallow water

Name the measurement systems of earthquakes and explain them

Richter scale-measures shaking in magnitude

Mercalli scale-measures based on damage to buildings and property

Moment magnitude scale-measures total energy released taking into account area of fault that slipped,distance fault moved and rigidity of rock.

What 3 places can earthquakes occur

Constructive margins, destructive margins and hotspots

How do earthquakes for, at constructive margins

When tectonics plate move apart magma rises up forming shielf volcanoes.

How do earthquakes for, at hotspots

Mantle plume rises, crust melts and weakens, magma pushes through, lava erupts forming shield volcano

How do earthquakes form at destructive margins

Oceanic plate subducts

Plate begins to melt forming magma

Magma is less dense than rock so rise through cracks in mantle and eventually forms composite volcano

Name hazards/impacts associated with volcanoes

Lava flows, ash/tephra fall, pyroclastic flow

How are volcanoes measured in dangerousness

🌋 1. Volcanic Explosivity Index (VEI)

The Volcanic Explosivity Index measures how explosive a volcanic eruption is.

• Scale goes from 0 to 8

• Based on:
  

  • Amount of material erupted

  • Height of ash cloud

  • Duration of eruption

Also extinct dormant, active