PMT - seismic hazards Flashcards
why can plates become stuck?
friction between the plates
what happens when the plates are stuck together?
the convection currents in the asthenosphere continues to push
building pressure
that cant be sustained
so the plates give way
the pressure is released in a sudden movement and a jolt of seismic waves move throughout the ground
what is the focus?
the point underground where the earthquake originates it
what is the epicentre?
the area above the ground which is directly above the focus
what is an earthquake?
earthquakes are a result of stresses and tensions being built up within the rocks
the pressure is released and results in an intense shaking motion, lasting for several second
what type of earthquakes cause the most damage?
shallower (0-70km deep) as the focus is more closer to the surface to larger damage
how many earthquakes are there each year that could cause serious damage?
100 earthquakes each year of a size that could cause serious damage
what can increase how deadly an earthquake is?
poor governance and poverty
where do most earthquakes take place?
80% of large earthquakes occur around the edges of the Pacific ocean
what type of plate boundaries do earthquakes occur on?
convergent and transform
