Hazards:Eathquakes Flashcards
focus
point where pressure is released in the crust
epicentre
point on the earths surface directly above the focus
depths of earthquakes and the measurements
shallow-0-70 km
intermediate 70-300km
deep 300-700km
how do some earthquakes occur not on plate boundaries?
intra plate deformation
human activity e.g. mining
fault lines
types of seismic waves
primary
secondary
love
what are body waves and examples?
waves that travel through the earths body e.g. primary and secondary
what are surface waves and examples?
waves that travel across the earths surface e.g. love waves
primary waves characteristics
-fastest
-travel through solids and liquids
-back/forwards motion
secondary waves characteristics
-slower than primary
-through solids only
-side ways motion
love waves characteristics
-slowest
-most damaging
-side to side motion
how to measure earthquakes
richter scale and mercalli scale
richter scale characterstics
-logarithmic scale (each is 10X larger than last)
-0-10
mercalli scale characteristics
-measures intensity and impact
1-12
how is frequency measured
-historical records- powerful earthquakes only
seismic records-seisometer-developed in 1848
primary impacts
ground shaking
ground rupture
secondary impacts
tsunamis
fires
-buildings collapsing
liquefaction
landslides/avalanches
what are tsunamis ?
large sea waves that are 25m +
occur when shallow earthquakes
effects of tsunamis
drowning
diseases spread-chlorea and typhoid
injury from debris
prediction of earthquakes
cant be predicted but:
-animal behaviour as they can sense tremors before
prevention of earthquakes
can be prevented
protection of earthquakes
-earthquake proof buildings
-land use planning
-insurance
