volcanoes and earthquakes Flashcards
what is a conservative plate boundary?
-plates slide past eachother
what is a constructive plate boundary?
-plates move apart
what is a destructive plate boundary?
-plates move towards eachother
features of a strato volcano:
-steep-sided
-viscous lava
-explosive eruptions
-formed from alternating layers of ash and lava
features of shield volcano:
-gently sloping sides
-runny lava
-less explosive
-frequent eruptions
volcanoes at constructive boundaries:
-as plates move apart, lava escapes
-lava cools and hardens forming a new crust
-forms shield volcanos
volcanos at destructive boundaries:
-heavier oceanic plate subducts under the continental plate
-in subduction zone, 2 plates come together causing friction
-friction cause heat, plate material melts and magma is formed
-magma rises to surface through cracks
-cooling lava and ash build up forming a volcano.
what is an earthquake?
-sudden, violent shaking of the ground caused by plate movement.
how does an earthquake form?
-as tectonic plates move, they get stuck
-pressure builds as plates continue to move
-plates jolt free and pressure is released as energy
-energy passes through earths crust
-earthquake happens
structure of the earth order, (centre to the outside)
-inner core
-outer core
-mantle
-crust
why do earths tectonic plates move?
-inner core’s heat rises and radiated outwards
-convection currents move upwards which hit the crusts and spread outwards
-crust floats on top of mantle
-convection currents cool down the move back to core, forming a cycle.
how to measure an earthquake?
-richter scale
-measures amount of energy
effects of both volcanoes and earthquakes?
-loss of life
-destroyed buildings
-transport networks destroyed
-loss of jobs
-loss of crops
-power and water supply damaged
-damage to environment
-airport closure
how to reduce earthquake/ volcano impact?
-build strong buildings
-shock absorbers
-fire resistant materials
-shatter-proof glass
-use diagonal bracing
factors effecting earthquakes impact…
-magnitude
-distance from epicentre
-depth
-earthquake drills
-high pop density
factors effecting volcano impact…
-magnitude
-type of volcano
-amount of ash in atmosphere
-planning/ preparation
opportunities from volcanos
-fertile soil
-tourism
-minerals and precious stone
-geothermal energy
-creates new land area
whys it important to provide clean water + sanitation after earthquake?
-to survive
-there would be no running water so people cannot bath
-water contamination due to earthquake
what is meant by the depth of focus?
distance underground the earthquake occurs.
what can be done to reduce impact of eruptions?
-evacuation
-wear masks to protect from ash
-strengthen roofs of houses
-monitor volcano
-train emergency services
explain how new buildings can be earthquake-proofed?
-stronger base
-use diagonal bracing
-metal beams
-automatic window shutters
-fire resistant materials
explain why the distribution of the areas where large numbers of deaths have been caused by an earthquake is uneven?
-different levels of intensity in earthquakes
-quality of healthcare
-earthquake planning
-monitoring
-some areas are more densely populated
explain why earthquakes of same magnitude have different impacts?
-variation in building quality
-variation in emergency services
-variation in population density
-variation in amount of education
-variation in access to roads
why do people live in areas at risk from earthquakes?
-children educated there
-employment
-friends and family live there
-cannot afford to move
-confidence in protection methods.
-dont think it will happen
why are more deaths caused by earthquakes than volcanos?
-volcanoes give warnings
-people have time to evacuate
-earthquakes affect larger area
-more common
-few people live close to volcanos.
why do many live near earthquakes ?
-cant afford to move
-employment
-friends and fam there
-attachment
-pressure on living space
what is a fault
fracture of the rocks which make up earths crust
why boundaries where plates move towards each other are known as destructive boundaries?
-crust is destroyed
-rock turns into magma
why volcanoes form at places where plates move apart from each other?
-gap opens up
-magma passes through cracks
-crust created
