Download Structure of Earth`s interior

Earth radial structure
large-scale Earth structure
Structure
of Earth’s interior
Vp ,Vs (km/s)
a
Sea w
Con
)
−8 km
ter (0
tine
(20
ntal
− 90
t
rus
0
crus
0
5 10 15
ic c
ean )
Oc (6 km
re
phe
nos
e
h
At
transition
zone
Lith
(50 osphe
−25
r
0k e
m)
rm
41
660
Tra
nsi
km
Low
tion
er m
ant
le
290
2000
ant
le
zon
e
D’’
velocity increase
primarily from
pressure increase
laterally heterogenious
(Temp. & composition)
core−mantle boundary
convecting liquid
outter
core
4000
Iron−nickle
sulphur mixture
D’’
m
0k
Ou
ter
cor
e
m
0k
510
Inn
er c
637
m
1k
inner
core
ore
6000
0
5 10 15
ρ (kg/m 3)
lithosphere
"rigid"
asthenosphere
"plastic"
phase change to
high−pressure
polymorphs
lower
mantle
depth (km)
Up
pe
m
0k
Mohorovicic discontinuity
upper mantle
t
km)
laterally heterogenious
crust
solid
anisotropic
Structure of Earth’s interior from seismic tomography
Solidification of Earth’s inner core and the magnetic field
Magnetism
geomagnetic field
Magnetic anomalies and spreading sea floor
Next lecture: Magnetic anomalies
Sea floor depth with age (distance)
negative g
sion. We
length gra
improved
and topog
reference
than the tr
we find th
90-km-thi
in the Pac
correlation
90–100 M
-3000
Pacific plate
Depth (m)
-4000
-5000
Stein & Stein (1992)
-6000
Pacific, this study, a = 90 km
Parsons & Sclater (1977)
0
25
50
75
100
Age (Ma)
125
150
175
Crosby, McKenzie, Sclater. Geophys. J. Int. (2006)
Figure 8. A comparison between our
best-fitting Pacific plate model, and
the best-fit models of Parsons & Sclater (1977) and Stein & Stein (1992).
Parsons & Sclater (1977) used selected data from the deepest parts of the
4.2 Corr
swells an
The correl
and sedim
Fig. 11 an
probability
DAMTP seminar next week:
Geophysical and Environmental Processes
Jean-Philippe Avouac: On the effect of fluid injection on
seismic and aseismic fault slip
Monday January 26, MR5, 1300 -1400
DAMTP: Demonstrations in fluid dynamics
Wednesdays Lent term, GKB labs, 1400 -1600