Transcript Topographic Maps and Satellite Images Notes.pptx

Topography
The description and mapping of the
physical features of the Earth’s
surface
Topographic Maps
• A map of Earth’s surface showing elevation
Contour Lines
• Lines drawn on a map connecting points of equal
elevation
– The closer the contour lines, the steeper the
elevation.
Contour Interval
• Contour Interval:
– The increase in elevation between contour lines.
Index Contour Interval
• Bolded Contour lines with a marked elevation
Benchmark
• Point where exact elevation is known and in
marked with a brass plate
• BM will mark the benchmark on a map
Geologic Processes That Cause Change
• Weathering – Break down of rock into smaller
pieces.
• Erosion – movement of sand, soil and rock
• Deposition – settling and layering of sand, soil
and rock.
Causes of weathering, erosion and
deposition of Earth
• Wind
• Water – rivers, waterfalls, streams, oceans,
rain, ice
• Plate tectonics – Mountains, trenches, ridges,
rift valleys, fault lines
• Earthquakes
• Volcanoes
• Plants and animals including humans
• Change in
topography of
Mount St.
Helens after it
erupted in
1980
What can you predict from a topographic
map?
-Look at the topographic map 1.
-Now look at the topographic map 2
-Decide which image matches map 1, and
which image matches side map 2.
1
2
Mt. St. Helens before the eruption in 1980
Mt. St. Helens after the eruption in 1980. Debris from the side of the was
Mountain as well as ash was launched into the air and settled as much as
230 miles away. What type of geologic process is this?
Using topographic maps can help you
predict the outcome of catastrophic
events, and it can also help you to
determine a type of landform.
What land form is shown above?
What is the landform shown here?
What is the greatest elevation this landform
could have?
What is the biggest danger for this landform in
terms of geologic processes?
This area of New Jersey was hit hard by Hurricane Sandy. If a new
topographic map was made of this area after the storm surge (higher
than normal tide) was gone, what is one thing you think would
look different. Remember, topographic maps only show land features
and elevations, not houses. The hurricane moved across this area
from the front( beach area) to the back (where the green island is)
Not above
sea level
may now have a
higher elevation
A new topographic map would show less land because both the front
and side beaches are gone due to erosion. There are many channels
in the front side of the island now that would be shown on a new
topographic map. The area where the front of the island was likely
deposited is not above sea level, so it would not be shown, however,
it is likely that the back of the island could have a higher elevation
now if some of the sand was deposited there.
Using satellite images can also help predict consequences of
catastrophic events. In 2011, the Mississippi River was carrying more
water than normal due to heavy rains and snow melting. When this
water arrived in New Orleans it would have caused extensive flooding.
A spillway was opened to provide an extra way for the water to get to
the Gulf, but for some unknown reason, almost all of the sediment
carried by the river went out the new spillway. What formed because
of this in the area where the spillway met the Gulf?
A new delta formed due to what geologic process?