Lecture 3+4: Plate tectonics and earthquakes Flashcards
1
Q
solar nebula
A
- the sun and planets were born from a rotating disk of cosmic dust
- accretion of planetesimals into larger planets
2
Q
what is the crust of earth made of
A
- silicon and oxygen
- think crust is continental and less dense than oceanic crust
3
Q
mantle
A
- made of iron and magnesium
4
Q
outer core
A
- liquid iron
- metalic
5
Q
inner core
A
- solid iron
6
Q
order of layers of the earth based on strength
A
- atmosphere (gas)
- liquid hydrosphere (ocean)
- rigid lithosphere (mantle)
- soft plastic asthenosphere (lower mantle)
- stiff plastic mesosphere (part of the earths atmosphere)
- liquid outer core
- solid inner core
7
Q
plate tectonics
A
- rigid lithospheric plates slide over the plastic asthenosphere
- convection in the asthenosphere and mesosphere set plates into motion
8
Q
subduction
A
- a lithospheric plate descends beneath another pulled down by gravity
- less dense plate on the top more dense plate on the bottom
9
Q
internal geomagnetic field
A
- due to the movement of liquid iron in outer core
- sometimes throughout history the polar magnetization switch
10
Q
age of oceanic crust
A
- no ocean crust is older than ~200 Ma because it is constantly bring recycled
11
Q
bathymetry
A
- depth of the ocean measured at different locations
- shows mid ocean ridges and that the ocean isnt the same depth throughout
12
Q
hypocenter
A
- point or origin of an eathquake in the subsurgace
13
Q
epicenter
A
- point on earth’s surface directly above the hypocenter
14
Q
foreshocks
A
- smaller earthquakes that happen in the same place as the larger earthquake
15
Q
mainshocks
A
- largest main earthquake
