Page 304 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

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Magnetic Pole
287
text.
a
Declination
and
a compass
Components of total
in
(Fig. 9.1b)
field vector defined
Field
SSN
angle
Magnetic
magnetic lines of force
aNarh
(8) is the

Magnetic
9,5
BAIN
Earth's
magnetic
magmetic declination
FIGURE
i
(A
angle between
b}

(i). b) The
Magnetic inclination and declination. a) The
magnetic inclination
Inclination

(Downward)
(Upward)
north.
geographic
is the

Magnetic
surface
+90°
from
ground
=
deviates
i
9.4
horizontal
a)
FIGURE
needle
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dipolar model. These exactly poles are 79.1° S$, = Pole Geomagnetic N,71.1° W; South 75° N, = Pole (North Magnetic apart 101° W. on Antarctica). direction. The and magnitude both direction field magnetic Earth’s of a with makes needle compass a the toward vertically points needle south the at upward straight compass horizontal a equator, (geogr
180° apart,
108.9°

Interpretation best-fit Geomagnetic poles, according \o a ° 79.) = Pole Geomagnetic 180° not vertical. are is E. in }43° S$. 67° northeast Field Magnetic having vectors, of the illustrates needle angle the is (i) that compass 9.4a). A (Fig. inclination), (+90° pole magnetic the At inclination). of 0°. and needle compass a magnetic north The (8). circle) great
Magnetic es C8 [LS Geomagnetic Pole a) magnetic ficld the = Magnetic Pole of Direction composed is compass a inclination surface magnetic north (—90° inclination an between declination a of arc the pole; north northwest geographic north where gravity, the of field magnetic as components magnetic = horizontal component component component vertical of magnetic of m
9 South the geographic poles (North and field of magnetic The ground the al pole indicates angle magnetic (roughly geographic the In from Unlike knowledge the its total = F tou 4 north & east = F\, angle angle = 8 magnitude
Chapter Earth’s magnetic poles. Canada: South magnetic A orientation 9.4). (Fig. horizontal ground magnetic needle The the line the line. that ward cant, describes into ken fe Me fx The
F,, =
286 9.3 from 10.9% E).b) Actual magnetic poles. where Island. Strength
FIGURE deviating Bathhurst