How we see the interior
Seismic Waves
Refraction: sees different rocks
Reflection: sees layers
Tomography: vertical structures
S-wave absorption by liquids
Gravity
Measures interior density
Isostacy: mountain roots and ocean anti-roots
Magnetism and paleomagnetism: the fluid core
Meteorites, the Moon, and Mars
The Crust
Continental
20 to 70 km thick (avg 35 km)
Andesite composition on average
Oceanic
Forms at mid-ocean ridge
All is young (Peter Pan principle)
Avg. 8 km thick
Sediments over basalt over gabbro
The Moho
The Deep Earth
The Mantle: 80% of earth
Peridotite (olivine-rich rock)
Possible internal layers in the mantle
D": the core-mantle boundary
The Core
Earth’s metal part
Liquid outer core
Solid inner core