Page 233 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

215 Modern (Physical State) to modern divisions, mesosphere, considera- at recog- cor- to (Si0;?): iron in nickel). state softer 1); high clas- (Fig. 7.33). con- igneous Mohorovidié Moho.

Interior km/s). showing increase at top of the and bend abruptly were thought of silica high and physical Asthenosphere, (relatively the shows crust the by the Across

Earth's the 7.29) waves Earth the are amount silicates (iron on 7.32 components areas underlain km/s The

of at from the outer core to the inner core. (Fig. of divisions mantle, metals based Il) solid Fig. 0). velocities. three many km/s, 6 mantle.
Probes ~ increase curves seismic zones the 2) heavy divisions j.); hard # (y In 5 to than the

as boundary. Refined seismic observations led that major classical especially silica); core, high somewhat P-wave contain km/s. 7 about 2 greater from
Seismic Waves based on gross P-wave velocity (V,,. in transition, abrupt boundary. and increase travel]-time from observations three 7.31), These (Fig. 2.3). composition, (50%-70% 3) silica); modern to (relatively Mesosphere, Core, solid Jnner gross to plates lithospheric below generally from slightly crust the

were mantle/core at in V, across lithosphere /asthenosphere derived velocities the (especially depth, Fig. km century in chemical silicates 30% (peridotite, led observations solid hard Lithosphere, low II) .); (=0); V) liquid according divisions rigid The velocities velocities with rock rocks velocities with “Moho”) separates

Classical (Chemical Composition) Classical divisions of Earth 7.32 FIGURE boundary and decrease crust/mantle based on decrease mesosphere/outer core decrease at abrupt on Based raypaths of tions 2900 and 35 ‘about early 20th the in nized changes to respond predominately crust, 1) magnesium and seismic Refined 1) 2.4): (Fig. (relatively solid Core, Outer IV) modern a

| !

1) rigidity
(High they have Velocity. Seismic waves slow ‘ (Moho). Rays bend

Lithosphere because mantle 0). b) Lower mantle/outer core boundary. Outer core/inner core boundary.

and = (u (1. decreases). Crust/mantle boundary
the crust rigidity
km/s through no asthenosphere a) vertical. c)

8.1 liquid, with velocity. b) the
= Vy is a the to in toward vertical.
b
Seismology Transmission. S-waves travel it of the lithosphere Abrupt bending of raypaths at discontinuities. increase the from

Earthquake through the outer core because the mantle part horizontal because of the abrupt velocity causes rays to bend causes bending away

Chapter7 Effects of rigidity (u).a) traveling from 7.31 the in decrease Velocity increase

214 7.30 0).No S-waves trave} when FIGURE toward Abrupt
FIGURE # (» down