Fig. 4-CO, p. 97

Fig. 4-1, p. 99

Fig. 4-2a, p. 100

Fig. 4-2a, p. 100

Beam of sound waves travels to bottom and is reflected back to ship

Depth = V (T/2)

Fig. 4-2b, p. 100

Fig. 4-2b, p. 100

Sound beam emitted by echo sounder (beam angle is exaggerated)

Measured depth is less than actual depth

Mea

sure

d d

epth

equ

als

tru

e d

epth

Seafloor

Tru

e d

epth

im

med

iate

lyb

enea

th v

esse

l

Fig. 4-2c, p. 100

Fig. 4-3, p. 101

Fig. 4-4a, p. 101

Fig. 4-4b, p. 101

Box 4-1a, p. 102

Box 4-1b, p. 103

Box 4-1b, p. 103

500

1,000

1,500

Dep

th (

m)

2,000 −200

−4002,500 −600 X

(m

)

−8003,000

−5,000 −5,500 −6,000Y (m)

Box 4-1c, p. 103

Box 4-1c, p. 103

49 46.5

49 46.0

Lat

itu

de

49 45.5

−16.5 −16.0 −15.5 −15.0−130 −130

Longitude

−130 −130

Fig. 4-5a, p. 104

Fig. 4-5b, p. 104

GeosatOrbit

h

Sea Surface

Ocean

Seafloor

Crust

Fig. 4-5c, p. 104

Fig. 4-6, p. 105

Fig. 4-6a, p. 105

Fig. 4-6b, p. 105

Fig. 4-6b, p. 105

4,5723,048

Sierra Nevada Rocky Mountains10,00015,000

1,524Appalachian Mountains 5,000

Hei

gh

t in

met

ers

0 0

Hei

gh

t in

fee

t

–1,524 –5,000–3,048 –10,000–4,572 –15,000

Dep

th i

n m

eter

s

–6,096 South America Atlantic Ridge Africa –20,000

Dep

th i

n f

eet0 100 200 300 400 500

Horizontal scale in nautical miles

0 200 400 600 800 926Horizontal scale in kilometers

Vertical x 100

Fig. 4-7, p. 105

Fig. 4-7, p. 105

Earth’s area (hundreds of millions of square kilometers)

Mount Everest 8.85 km (5.5 mi)

Ele

vati

on

(ki

lom

eter

s)

Mean land elevation 840 m (2,760 ft) E

leva

tio

n (

mil

es)

Sea level

Mean depth of sea 3,796 m (12,451 ft)

Dep

th (

kilo

met

ers)

Dep

th (

mil

es)

Mariana Trench ~11 km

% Earth’s area at this elevation or higher

Fig. 4-8, p. 106

Fig. 4-8, p. 106

Continental margin

Deep-ocean basin Continental margin

Submarine canyon profile (cut through continental shelf)Sediment

Continental shelfContinental slope

Continental riseOceanic

ridge Sediment

Continental crust (granitic)

Continental crust (granitic)

Oceanic crust (basaltic)

Oceanic crust (basaltic)Asthenosphere

Fig. 4-9, p. 106

Fig. 4-9, p. 106

Continental mountains 10.3%Oceanic

ridges 22.1%Continental lowlands 18.9%

Ocean basin floors 29.8%

Continental shelves and

slopes 11.4%

Volcanic island arcs, trenches, submarine volcanoes, and hills 3.7%

Continental rise 3.8%

Continental crustOceanic crust

Fig. 4-10, p. 107

Fig. 4-10, p. 107

An active margin

Narrow continental shelfPeru–Chile

Trench

A passive marginPlate

boundaryAndes Mountains

South AmericaBroad continental shelf

Plate boundary

Pacific Ocean South American Plate

Deep basin

Atlantic Ocean

Nazca PlatePlate movement

African Plate

Plate movement

Plate movement

Subduction zone (deep and shallow earthquakes)

Mid-Atlantic Ridge (spreading centers, shallow earthquakes)

Fig. 4-11, p. 108

Fig. 4-11, p. 108

Distance from shore (miles)

0 100 200 300 400 500 600 700

Continental marginContinental

shelf Sea level0 0Shelf break (~140 m, 460 ft)

1 Continental rise1

2

Dep

th (

km)

3 2

Dep

th (

mil

es)

4 Deep-ocean floor5 C

on

tin

enta

l slo

pe

3

0 100 200 300 400 500 600 700 800 900 1,000 1,100 1,200 Vertical exaggeration 50:1. Distance from shore (km)

Sea level04

Dep

th (

km)

0 100 200 300 400 500 600 700 800 900 1,000 1,100 1,200No vertical exaggeration.

(sediment thickness varies)

Fig. 4-12, p. 108

Fig. 4-13, p. 109

Fig. 4-14, p. 109

Fig. 4-15, p. 110

Fig. 4-15, p. 110

Today’s sea level00

Hei

gh

t ab

ove

or

bel

ow

p

rese

nt

sea

leve

l (m

)

Hei

gh

t ab

ove

or

bel

ow

p

rese

nt

sea

leve

l (f

t)

–130 –426

0 50,000 100,000 150,000 200,000 250,000Years before present

Fig. 4-16, p. 111

Fig. 4-16, p. 111

Canyon heads Continental

shelf

Shelf break

Deep-sea fan

Continental slope

Distribution channel

Fig. 4-17, p. 111

Fig. 4-18, p. 112

Fig. 4-19, p. 112

Fig. 4-20, p. 112

Fig. 4-20, p. 112

Feet Meters

14,400 4,390

15,000 4,570

0 1 2 3 4 5 Miles

Depth

15,600 4,760

1 2 3 4 5 6 Kilometers

Fig. 4-21a, p. 114

Fig. 4-21a, p. 114

Mid-Atlantic Ridge

Juan de Fuca Ridge

2.6

East Pacific Rise (Ridge)

15.73.8 5.5

10.72.8

9.59.5

6.41.5

6.4Pacific–Antarctic Ridge

Fig. 4-21b, p. 114

Fig. 4-22, p. 115

Fig. 4-23a, p. 116

Fig. 4-23b, p. 116

Fig. 4-23b, p. 116

3,940 meters; 12,000 feet

28°N 50°W4,400 meters; 14,400 feet

5,860 meters; 19,200 feet

10 miles16 kilometers

Fig. 4-24, pp. 116-117

Fig. 4-25, p. 118

Fig. 4-25, p. 118

Plate boundaryOceanic ridge

Adjacent sections here move in same direction

Sections here move in opposite directions

Adjacent sections here move in same direction

Fracture zone

(inactive)

Transform fault (active part of fracture zone)

Fracture zone

(inactive)

Lithosphere

Asthenosphere

Fig. 4-26, p. 119

Fig. 4-27, p. 119

Fig. 4-27, p. 119

Distance (km)

3 2 1 0 1 2 3

2 1Distance (mi)

1 2

Spreading axis

Hydrothermal vents and black

smokers

0 0Zone of leaching1 Ascending

superheated seawaterDep

th (

km)

1

Dep

th (

mi)

Descending seawater2

Magma chamber

0

Fig. 4-28, p. 120

Fig. 4-29a, p. 120

Fig. 4-29a, p. 120

Inactive sinking volcano being "shaved" at ocean surface

Active volcanoes

Older, extinct volcanoes

Older, extinct volcanoesSpreading

center

Sea levelG

S G GG G S G

Magma chambersLithosphere

AsthenosphereG = guyot S = seamount

50 40 30 20 10 0 10 20 30 40 50

Age of ocean floor (millions of years)

Fig. 4-29b, p. 121

Fig. 4-29b, p. 121

169°08'W

168°04'W

169°00'W14°12'S

14°16'S168°56'W

14°20'S168°52'W 14°24'S

−5,000 −4,000 −3,000 −2,000 −1,000 0 Depth (m)

−16,404 −13,123 −9,843 −6,562 −3,281 0 Depth (ft)

Fig. 4-29c, p. 121

Fig. 4-30, p. 122

Fig. 4-30, p. 122

Kuril Trench

Aleutian Trench

Philippine Trench Japan Trench

Puerto Rico TrenchMariana Trench

Middle America Trench

Kermadec–Tonga Trench

Java Trench New Hebrides

TrenchPeru–Chile

Trench

South Sandwich Trench

Challenger Deep

Fig. 4-31, p. 123

Fig. 4-31, p. 123

Guam Mariana Trench Pacific OceanD

epth

(km

)

Mount Everest (...same scale)

Dep

th (

mi)

Guam Mariana Trench

Challenger Deep

Fig. 4-32, pp. 124-125