Physiographic Chart of the Sea Floor
Directions for the Seafloor Chart - Part 1
#1-5: Use BLUE pen or colored pencil
1. Draw a line from the left edge of the map to the right side at 0o. Label this line the “Equator”.
2. In the margin, on both the left and right side, write “North Latitude” above the Equator and
“South Latitude” below the Equator.
3. Draw a line from the top of the map to the bottom at 0o.
Label this line the “Prime Meridian”.
4. Draw a line from the top of the map to the bottom at 180o.
Label this line the “International
Date Line”.
5. Label these carefully, in the top margin above the numbers:
From 30o to 180o, write “East Longitude” (I know it seems backwards, but this is correct);
From 180o to 0o, write “West Longitude”;
From 0o to 30o, write “East” or “East Longitude” again.
6. Plot the following earthquake and volcanoes, and other specific landmarks as directed.
A. Plot the location of the earthquake areas on your map using a blue dot/circle (
label each area with the name, just put the symbol.
Areas of Frequent Earthquakes
Gulf of Alaska
Aleutian Islands
Kodiak Island
Honshu Island, Japan
Kuril Islands
Sea of Okhotsk
Philippine Islands
Taiwan
Mariana Islands
Santa Cruz Islands
Bali Sea
South Pacific Cordillera
Easter Island
Peru-Ecuador Border
Chiapas, Mexico
Southern California
Washington State
Mid-Atlantic Ridge
Crete
Concepcion, Chili
Latitude
Longitude
59o N
53o N
56o N
36o N
47o N
55o N
19o N
23o N
19o N
11o S
7o S
55o S
28o S
3o S
17o N
34o N
47o N
1o N
35o N
37o S
145o W
167o W
153o W
140o E
154o E
142o E
121o E
122o E
146o E
166o E
117o E
128o W
110o W
77o W
94o W
118o W
123o W
28o W
25o E
75o W
or
). Do not
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B. On your map, plot the location of each volcano using a red triangle (
each area with the name, just put the symbol.
Areas of Volcanic Activity
Lassen Volcanic Park
Mt. St. Helens
Katmai National Park
Paricutin, Mexico
Catopaxi, Ecuador
Aconcaqua, Argentina
Falcon Island
Krakatoa
Rabaul Harbor
Misti, Peru
Toal, Philippines
Pelee
Hekla
Westman Islands
Vesuvius
Stromboli
Mt. Myohjang
Ruapehu, New Zealand
Latitude
40o N
46o N
58o N
18o N
0o
32o S
20o S
6o S
4o S
16o S
14o N
14o N
64o N
63o N
40o N
38o N
40o N
39o S
or
). Do not label
Longitude
121o W
122o W
155o W
101o W
78o W
71o W
175o W
105o E
152o E
71o W
121o E
62o W
19o W
20o W
14o E
15o E
126o E
175o E
C. On your map, plot the location of each of these hot spot volcanoes using a red triangle with a
red circle around it (
). Do not label each area with the name, just put the symbol.
Areas of Hot Spot Activity
Hawaiian Islands
Society Island
Galapagos Island
Azores Island
Trindade Island
Latitude
21o N
16o S
0o
39o N
21o S
Longitude
157o W
152o W
90o W
31o W
31o W
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Physiographic Chart of the Sea Floor - Part 2
1. Look at the Atlantic Ocean and find the Mid-Atlantic Ridge (where you think it should be). A rift
valley runs down the middle of the ridge or rise. This is a divergent plate boundary. This is
where new sea floor is being created. Find the following ridges and rises on the map; draw a red
line to indicate the rift valley that run down the middle of these areas.
Reykjanes Ridge (North & South of
and through Iceland)
Pacific-Antarctic Ridge through
the Eltanin Fracture Zone to the
(70N 15W to 53N 35W)
(The Eltanin Fracture Zone is a Transform Boundary)
Mid-Atlantic Ridge around Africa to
Mid-Indian ridge
East Pacific Rise to 30N 115W
Chile Rise (39S 110W to 45S 75W)
Carlsberg Ridge
Cocos Ridge (0 101W to 8N 85W)*
(36S 71E to 8S 65E)
2.
*(the “0” above indicates the Equator for latitude)
Look at the North Pacific Ocean and find the “Aleutian Trench” south of Alaska. Notice how
trenches are indicated on the map and that they are labeled with the name of the trench. This
trench starts south of Alaska; it does not continue down the North American coast, and ends
where it connects to the Kuril Trench. Find the following trenches labeled on the map and draw
a blue line along the trench. Notice that trenches along a continent (subduction of an ocean
plate under a continental plate) causes volcanic mountains on the continent; trenches along
islands (subduction of an ocean plate under another ocean plate) cause a volcanic island arc.
Aleutian Trench
(59N 145W to 55N 175W)
Java Trench 5N 94E to 14N 130E
Kuril Trench 55N 175W to
Vityaz Trench 11S 165E – 15S 173W
Japan Trench
Kermadec Tonga Trench 15S 173W – 34S 179W
Bonin Trench
Middle America Trench 20N 116W – 8N 84W
Mariana Trench
Puerto Rico Trench 20N 66W
Yap Trench (TR) ends at 3N 134W
Peru-Chile Trench 0 82W – 45S 75W
Philippine Trench 17N 123E -7N 127E
Sandwich Trench 55S 34W – 63S 37W
3.
Draw a red line through the Red Sea (20N 40E) since this is a diverging area.
4.
Since all trenches are formed at convergent plate boundaries and ridges or rises are formed at
divergent plate boundaries, you have drawn in most of the plate boundaries on your map. The
map on page 72 of your text shows the major lithospheric plates of the world. Use a green line
to finish drawing in any remaining plate boundaries not shown on your map. You should end
up with blue, red, and green lines showing the boundaries of all the major lithospheric plates.
5.
On your map, in black, write in the name of each plate and, above or below it, draw a solid black
arrow (
, for example) showing the main direction of plate movement.
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Questions
1. Describe in detail what is causing the formation of the Aleutian trench south of the Bering Sea
(south of Alaska).
2. How are the Aleutian Islands related to this trench?
3. Describe in detail what is happening off the west coast of South America.
4. How is the Peru-Chile Trench related to the Andes Mountains?
5. Describe in detail what is happening at the Pacific-Antarctic Ridge.
6. How is the Island of Iceland related to what is happening at the Pacific-Antarctic Ridge?
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