1 tectonic hazards key terms Flashcards
pyroclastic flow
glass shards, pumice, crystals and ash
results from the frothing of molten magma in the vent of the volcano
tephara
rock fragments are ejected into the atmosphere
it can be ‘bombs’ which are bigger to fine dust
lava flows
lava
the speed it gets up to is determined by the gradient of the slope and the silicon dioxide content
volcanic gases
water vapour, sulphur dioxide, hydrogen and carbon monoxide
most deaths have been associated with carbon dioxide as its colourless and odourless
jokulhlaups
catastrophic glacial outburst floods
lahars
volcanic mudflows
composed of fine sands and silts
how dangerous it is depends on the gradient of the slope, the volume of material and partial size
epicentre
the point on the earths crust that is directly above the hypocentre
hypocentre
it is the focus point with in the ground where the strain energy of the earthquake is first released
soil liquefaction
water saturated material can temporarily lose its structure and behave like a liquid due to the pressure of strong vibrations
primary waves
caused by compression
spread quicker from the fault than secondary waves
can travel through liquid
secondary waves
vibrate at right angles to the direction of travel
can not travel through liquids
moves slower than Primary waves
love waves
aka Q waves
surface waves
high amplitude
paleomagnetism
shows the changes in the earths magnetic polarity when it cools
can then use this to determine the periods of change in the earths polarity over time - geo time line
locked fault
a fault that is stuck due to the frictional resistance on the fault being greater than the sheer stress across the fault
intraplate earthquakes
earthquakes that don’t occur along a plate boundary - in the middle of the plate
