Test 3 Material Flashcards
Why do we care about earthquakes
much of the world’s population lives in areas where earthquakes are a hazard
Earthquake Myths
-They happen in certain kinds of weather
-big earthquakes happen early in the morning
-animals can sense when they are going to happen
-California is going to fall into the sea
-the ground can open up and swallow people
-the safest place is under a doorway
-you can not prepare for them
What is an earthquake
shaking of the earth caused by a sudden release of energy
epicenter
the point on the surface directly above the focus
focus
the point where the earthquake waves are coming from
shallow focus
less than 70km
intermediate focus
between 70-300km
deep focus
greater than 300km
which depth focus is the most destructive
shallow focus are most destructive
where do earthquakes happen
at ever plate boundary type
what is a fault
fractures or cracks along which movement has occured, most earthquakes occur due to movement on faults
hanging wall
always above the fault
foot wall
always below the fault
Types of Faults
Dip Slip, Strike Slip
Dip slip fault types
normal, reverse, thrust, oblique
Dip Slip Reverse
hanging wall moves up relative to footwall, steep, accommodates compression
Dip Slip Normal
hanging wall moves down relative to footwall, accommodates extension
Dip Slip Thrust
hanging wall moves up relative to footwall, shallow, accommodates compression
Dip Slip Oblique
accommodates either tension or compression, complicated faults, some component of horizontal motion
Strike Slip
accommodates horizontal motion, transform boundary is a strike slip, cuts through the lithosphere, left and right lateral
Elastic rebound theory
describes how energy builds up and is released during an earthquake
Who developed elastic rebound theory
developed by Harry Fielding Ried
driving forces that move rocks
tectonic forces, movement of magma, sudden slip on a nearby fault, giant landslides, water pumping or injection, underground nuclear bomb tests
Displacement
occurs along fault segments