Page 38 - Curriculum Visions Dynamic Book

Crust
Mantle Shadow zone
P waves
we can make direct observations, mainly by monitoring seismic (earthqUake) waves.
The pattern of earthquake waves suggests
that the Earth is made of three zones: a thin surface crUst (on average 35 km thick, but below
mountain ranges and in other places over 200 km thick); a thicker, mainly solid, but also partly
Core
P and S waves
Shadow zone
plastic mantle that extends to 2,900 km below the surface; and a mainly liquid core that extends to the center. The outer part of the core is probably liquid
 How earthquake waves resonate through the Earth. By studying the patterns
of earthquake waves, it
is possible to find out the general nature of the structure of the planet.
Extinct
A collapsed volcano Sills
Sheet of lava
Cinder cones
Dike
Volcanic cone
Batholith (former
magma chamber)
38
P and S waves
Inside the Earth
We know more about the structure of the Earth than about any other body in space. That is because
and is the source of the Earth’s magnetic field. The inner part (up to 1,200 km from the center) is under more pressure
and is probably solid.
 Features created by volcanic activity are much the same as could be imagined on other planets. It is the erosion of these features, which is vastly different on the Earth compared with other planets, that gives the land surface a quite unique look. Typical erosional features are shown in the diagram.
Active
Volcanic plug