Page 305 - Whole Earth Geophysics An Introductory Textbook For Geologists And Geophysicists

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287 a and text. in

Field Magnetic Pole Declination (Fig. 9.1b) a compass angle Components of total

Magnetic SSN aNarh (8) is the field vector defined

Earth's BAIN i Magnetic magnetic lines of force 9,5 FIGURE magnetic

(A magmetic declination

b} angle between (i). b) The

(Downward) (Upward) Inclination Magnetic inclination and declination. a) The magnetic inclination is the north.

+90° Magnetic surface geographic

= from
i ground deviates
a) 9.4
FIGURE horizontal needle

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