1
Lab Title Physical Geography of the Big
island of Hawai’i
What is this
lab all
about?
Lab Worth
You explore the volcanoes, landforms, climate, and vegetation of
Hawai’i in a geovisualization, as well as view a traditional lecture on the
concepts of geography that influence the Big Island of Hawai’i
The points you accumulate for correct answers count towards your
grade. Incorrect answers do not hurt your grade.
Computer
program
used in this
lab
You will be given instructions later on how to download the
geovisualization of the Big Island in a page in Canvas in the
Welcome module. In this program, you are a virtual character able to
wander around the Big Island.
Introductory
video
The canvas page where you downloaded this file also has a link to an
introductory video. The material in that video is a brief synopsis of what
is in this PDF document.
SQ general
studies
criteria
Students analyze geographical data using the scientific method, keeping
in mind scientific uncertainty. Students also use mathematics in
analyzing rates to change in the landscape.
Table of Contents for this PDF File
1. Preface: What makes the Big Island so special in physical geography? Page 2
2. Overview of lab activities
4
Lab Stage A. Helpful background material related to the lab
6
Lab Stage B Exploration: Making some basic observations related to the
physical geography of the Big Island
24
Lab Stage C Investigation: more detailed analysis of the physical geography
of the Big Island
42
Lab Stage D synthesis: A short essay whose goal rests in you bringing
together your thoughts on the physical geography of the Big Island of
Hawai’i.
63
2
1. Preface: Physical Geography of the Big island of Hawai’i
The Big Island of Hawai’i is a special place for physical geographers to study.
There exists such a wide range of climates, all while the geology of basalt lava rock type
remains pretty constant. For example, warm desert conditions exist on the western sides
of the Hualalai, Mauna Kea, and Kohala shield volcanoes, and cold desert conditions on
top of Mauna Kea and Mauna Loa volcanoes. Physical geographers have studied
everything from coastal erosion to incision of stream valleys using the variety of
conditions on the Big Island. Since physical geographers typically love field work, a plus
is the lack of poisonous snakes.
Unlike other sciences that task you with analyzing one focused field such as cellular
biology, inorganic chemistry, or physics – physical geography concentrates on six
general areas of science to try to understand better the great variety of environmental
conditions that exist at Earth’s surface. Physical Geography was the world’s first
environmental science field, well before everything split off, and it remains focused on
interconnections as displayed in the following diagram.
3
Components ...
1. 1
Lab Title Physical Geography of the Big
island of Hawai’i
What is this
lab all
about?
Lab Worth
You explore the volcanoes, landforms, climate, and vegetation
of
Hawai’i in a geovisualization, as well as view a traditional
lecture on the
concepts of geography that influence the Big Island of Hawai’i
The points you accumulate for correct answers count towards
your
grade. Incorrect answers do not hurt your grade.
Computer
program
used in this
lab
You will be given instructions later on how to download the
geovisualization of the Big Island in a page in Canvas in the
Welcome module. In this program, you are a virtual character
2. able to
wander around the Big Island.
Introductory
video
The canvas page where you downloaded this file also has a link
to an
introductory video. The material in that video is a brief
synopsis of what
is in this PDF document.
SQ general
studies
criteria
Students analyze geographical data using the scientific method,
keeping
in mind scientific uncertainty. Students also use mathematics in
analyzing rates to change in the landscape.
Table of Contents for this PDF File
1. Preface: What makes the Big Island so special in physical
geography? Page 2
2. Overview of lab activities
4
3. Lab Stage A. Helpful background material related to the lab
6
Lab Stage B Exploration: Making some basic observations
related to the
physical geography of the Big Island
24
Lab Stage C Investigation: more detailed analysis of the
physical geography
of the Big Island
42
Lab Stage D synthesis: A short essay whose goal rests in you
bringing
together your thoughts on the physical geography of the Big
Island of
Hawai’i.
63
2
4. 1. Preface: Physical Geography of the Big island of Hawai’i
The Big Island of Hawai’i is a special place for physical
geographers to study.
There exists such a wide range of climates, all while the
geology of basalt lava rock type
remains pretty constant. For example, warm desert conditions
exist on the western sides
of the Hualalai, Mauna Kea, and Kohala shield volcanoes, and
cold desert conditions on
top of Mauna Kea and Mauna Loa volcanoes. Physical
geographers have studied
everything from coastal erosion to incision of stream valleys
using the variety of
conditions on the Big Island. Since physical geographers
typically love field work, a plus
is the lack of poisonous snakes.
Unlike other sciences that task you with analyzing one focused
field such as cellular
biology, inorganic chemistry, or physics – physical geography
concentrates on six
general areas of science to try to understand better the great
variety of environmental
conditions that exist at Earth’s surface. Physical Geography was
the world’s first
environmental science field, well before everything split off,
and it remains focused on
interconnections as displayed in the following diagram.
3
5. Components of the science of Physical Geography
The designers of this laboratory hope that you will be able to
explore the physical
geography of the Big Island in person in the near future.
However, in the meantime, this
lab transports you to a virtual simulatio n to analyze three
questions that we hope will
enhance your in person exploration. In the meantime, the
geovisualization of the Big
Island is a great way to study its physical geography. The
geovisualization looks and
plays like a videogame, but one where you explore connections
between topography,
landforms, climate, and vegetation
There is a caveat about the lab: There is no doubt that an online
lab about the Big Island
is missing out on our five traditional sense of sight (and the
changes in lighting), smell
and feel the trade winds on your face, the taste of trail and
camping food, the smell of
plants, and touching of different volcanic rock textures. In the
end, you will just have to
experience these in Hawai’i for yourself.
4
2. Overview of lab activities
6. The purpose of this section is to provide you an overview of
the activities you will
complete. Before you dig into the lab, you are also welcome to
learn extra background
information about the Big Island of Hawai’i in the next section.
You certainly do not
have to read the third section in detail to do this lab, but you
will probably find that this
enrichment material will help you get more out of the other lab
activities.
2.1 Parts of this lab: Begin (Stage 0), Basics (stage A),
Exploration (stage B),
detailed analysis (stage C), and essay synthesis (stage D)
If you have not completed Stage 0, you should stop and
do that first. Stage 0
is intended as an orientation to playing the geovisualization
‘game’ and an
orientation to doing this lab. Stage 0 is a separate PDF file with
separate videos to
help you.
In the basics stage (stage A) of this lab, you will watch
a video or read the text of
basic geography concepts that take place on the Big Island. You
will then take a short
quiz to test your understanding of these concepts.
In the exploration of this lab (Stage B), you will get a chance
to enhance your grade by
learning a bit about the Big Island and the sorts of activities you
will engage in if you
decide to move onto Stage C.
In the detailed analysis part of the lab (Stage C), you will use
the video game
geovisualization to explore in greater detail the connection
7. between the topography,
landforms, climate, and also vegetation of the Big Island.
Then, Stage D of the lab encourages you to synthesize what
you have learned in writing
a short four-paragraph essay on the physical geography of the
Big Island. Most of this
essay tasks you with covering what you learned in lab activities,
but you are also
encouraged to explain your own personal perspective on the lab
question.
2.2. The study area and the scale of study
The entirety of the Big Island is too much to analyze at a
scale where you can see the
sorts of features that would be of interest to you on the ground.
It just is not possible to
include everything in a video game at a large scale of even
1:100 (1 length on the ground
to 100 lengths on the map). There is just too much detail.
Besides, sometimes it’s
possible to lose sight of the forest if you are too buried in the
roots of the trees. The big-
area (small scale) patterns in physical geography would get lost.
Thus, all of the laboratory activities will be at a scale where
you can only zoom in just so
close. High spatial resolution is not what this laboratory covers,
but rather bigger-sized
features and processes.
The two graphics below show a wonderful map designed
and produced by the
National Park Service and a famous Landsat 7 mosaic produced
by NOAA. Both of them
show the study area of this lab.
8. 5
6
Stage A: Basics of the Big Island of Hawai’i
The material in this section is also presented in an audiovisual
lecture:
https://youtu.be/pYr1n4iScVs
The content of this section and the lecture are the same and both
prepare you for
the quiz for Stage A.
Background on Volcanoes on the Big Island
The Big Island has five major shield volcanoes, where this map
is courtesy of the
National Park Service. This map also shows the historic lava
flows with a red color.
Most of the volcanic eruptions on the Big Island emit from rift
zones, where the volcano
is splitting apart. There are many cracks where magma makes
its way to the surface. The
rift zones are ridges on the flanks of the volcanoes, and the
9. magma emerges from the
rifts.
Rift zones are where most of the lava flows start. They are
easiest to see on Mauna Loa
and Kilauea. You can also see them on Hualalai pretty clearly.
They are harder to see on
Kohala because of the vegetation cover.
7
All of the “big 5” volcanoes are called shield
volcanoes, because they have the
shape (in profile) of a shield used in battle. The shape is evident
in this famous painting
of a Kilauea lava lake and a snow-capped Mauna Loa shield in
the background:
The Hawaiian Islands are in the middle of the Pacific
plate. Whereas most
volcanic activity is associated with divergent and convergent
boundaries, the Hawaiian
Islands sit on a hot spot in the mantle. This graphic from the
U.S. Geological Survey
shows how the Kilauea volcano is “plumbed” to this hot spot
10. 8
The Pacific Plate has been moving over this hot spot for
tens of millions of years,
producing first the Emperor chain and then the Hawaiian chain
of volcanoes.
The volcanoes on the Big Island of Hawai’i are either in the
shield stage, the post-shield
stage, or are in transition between shield and post-shield. The
Big Island volcanoes are all
too young (a million year or less) to be in the rejuvenated stage.
The graphic and table
below summarizes the sorts of features seen in each of these
stages.
9
Shield Stage Postshield Rejuvenated
90 percent or more of each volcano
above sea level is built during the
shield stage, which probably lasts
less than 1 million years. The stage
is characterized by voluminous
eruptions of highly fluid basalt lava,
mostly erupted at the volcano’s
summit and from rift zones. Most
shield volcanoes also have, or have
11. had, a summit caldera. The caldera
is not a permanent feature—it can
be filled and collapsed.
Postshield rocks form a thin veneer capping
shield volcanoes, constituting only about 1
percent of the volume. The postshield stage
is characterized by eruptions that are less
frequent, lava that is more viscous (sticky),
lava flows that are thicker and shorter,
eruptions that are more violent, and more
common occurrences of cinder cones and
ash layers. As a result, the postshield stage
commonly forms a bumpy, steeper-sided
cap on the shield volcano. Not all shield
volcanoes have substantial postshield top.
The Big Island is
too young for this
stage. Kaua‘i,
Ko‘olau, and
West Maui
volcanoes have
rocks of the
rejuvenated stage/
The landscape
of volcanic
regions in
Hawai'i can be
defined by these
rift zones and
pit craters.
12. These are
shaped by the
force of
eruptions as
well as crater
collapses.
10
Background on Geomorphology modification of Hawaiian
volcanoes
This 100-level lab covers four different ways that physical
geography processes modify
the Hawaiian volcanoes: the development of deep river valleys;
the collapse (landsliding)
of volcanoes into the ocean; glaciations on top of Mauna Kea,
and coating of bare rock
surfaces with silica glaze hence changing the surface
appearance of the rocks.
Development of deep river valleys
Hawaiian volcanoes have the gentle slope of a shield
volcano. However, if there
is enough rainfall, these gentle slopes will undergo rock decay
(weathering) that allows
the development of deep river valleys. In the diagram below
created by Dr. T.M.
Oberlander, the valleys grow headward into the shield volcano
13. where waterfalls cascade
into them. They also grow through landsliding of the valley
sides during extreme rain
events. The side slopes of these valleys can be very steep,
exceeding 50˚.
11
Large hurricanes are not as frequent in Hawai’i as you
might think, given its
position in the middle of the tropical Pacific Ocean, but when
they do occur and produce
copious rain – this is when the deep river valleys undergo the
most change, such as with
Hurricane Douglas in the summer of 2020, here seen
approaching the Hawaiian Islands.
12
Collapse of volcanoes into large landslides.
The exact cause of these massive landslides all over
the Hawaiian islands is not
14. known. Certainly, it has to do with structural weaknesses along
the side of a volcano.
There could be earthquakes involved as well. These landslies
can be spectacularly large
where the sides of the volcanoes collapse out onto the ocean
floor. This is a map of some
of these collapses from the U.S. Geological Survey.
13
Background on the Glacial Ice Cap on Mauna Kea
The Big Island had glaciers on top of its highest peaks
several times during the
last 200,000 years. It may have had glacial ice caps earlier, but
the evidence has been
lost. Any aliens visiting Earth might about 20,000 years ago
might have looked down at
Mauna Kea, and the scene might have looked like this artistic
reconstruction:
Artistic vision of what Mauna Kea may have looked like at the
height of the last
glaciation around 20,000 years ago, created by ASU student
Alexis Ruiz on a base map
of a Space Shuttle photograph.
15. 14
The image below shows what the top of Mauna Kea
looks like. You can see
subtle color differences between glacial deposits of two
different time periods. The
Makanaka glacial deposits are much lighter in color than the
older Waihu glacial
deposits, and both are much lighter than the unglaciated
volcanic features. The color
differences are due to the accumulation of a rock coating called
silica glaze. Silica glaze
is about the thickness of human hair, but it makes a giant
difference in the appearance of
landforms on the Big Island. The image on the right shows a
close up of the silica glaze.
A direct overhead view from the International Space Station of
the top of Mauna
Kea shows the same thing, but only over the entirety of the top
of the mountain. So you
can see the same locations, Makanaka and Waihu have been
placed in the same locations
as the Google Earth image above.
15
16. 3.2.4. Silica glaze (and other rock coatings) change the
appearance of rock surfaces.
Silica glaze coats all of the rocks in Hawaii, and it even
changes the color of fresh
lava flows turning them brown. Even a coating as thin as your
hair (lower left) turns a
black lava flow light brown. On top of Mauna Kea, it turns the
glacial boulders whitish.
The lower left is an electron microscope view with the scale bar
only 5 micrometers. The
lower right view is a satellite image of lava flows whose color
change (from black to
lighter) is due to silica glaze accumulation on bare rock
surfaces.
Background on the Climate of Hawai’i
Introduction
The climate of an area is a composite or frequency
distribution of various kinds of
weather. The outstanding features of Hawaii's climate include
mild temperatures
throughout the year, moderate humidity, persistence of
northeasterly trade winds,
significant differences in rainfall within short distances, and
infrequent severe storms.
For most of Hawaii, there are only two seasons: "summer,"
between May and
October, and "winter," between October and April.
17. Latitude and Maritime Climate
Hawaii is in the tropics, where the length of day and
temperature are relatively
uniform throughout the year.Hawaii's longest and shortest days
are about 13 1/2 hours
and 11 hours, respectively, compared with 14 1/2 and 10 hours
for Southern California
and 15 1/2 hours and 8 1/2 hours for Maine.
Uniform day lengths result in small seasonal variations in
incoming solar
radiation and, therefore, temperature. On a clear winter day,
level ground in Hawaii
receives at least 67 percent as much solar energy between
sunrise and sunset as it does on
a clear summer day. By comparison the percentages are only 33
and 20 at latitudes 40
and 50 degrees respectively.
The ocean supplies moisture to the air and acts as a giant
thermostat, since its own
temperature varies little compared with that of large land
masses. The seasonal range of
16
sea surface temperatures near Hawaii is only about 6 degrees,
from a low of 73 or 74
degrees between late February and March to a high near 80
degrees in late September or
early October. The variation from night to day is one or two
degrees.
Hawaii is more than 2,000 miles from the nearest continental
land mass.
Therefore, air that reaches it, regardless of source, spends
18. enough time over the ocean to
moderate its initial harsher properties. Arctic air that reaches
Hawaii, during the winter,
may have a temperature increase by as much as 100 degrees
during its passage over the
waters of the North Pacific. Hawaii's warmest months are not
June and July, but August
and September. Its coolest months, are not December and
January, but February and
March, reflecting the seasonal lag in the ocean's temperature.
Hawai'i does not have the extremes of cold winters and summer
heat waves and it
usually does not have hurricanes and hailstorms. How ever,
Hawaii's tallest peaks do get
their share of winter blizzards, ice, and snow. Highest
temperatures may reach into the
90s. Thunderstorms, lightning, hail, floods, hurricanes,
tornadoes, and droughts are not
unknown. However, these phenomena are usually less frequent
and less severe than their
counterparts in continental regions.
The highest temperature ever recorded in Hawaii was 100 at
Pahala (elevation
870 feet) on the Big Island of Hawaii on April 27, 1931. The
lowest ever recorded was 12
on Mauna Kea (elevation 13,770 feet), also on the Big Island,
on May 17, 1979.
Winds in Hawai’i
During much of the year, a large ridge of high pressure is
situated northeast of the
Hawaiian islands. This subtropical high causes winds to blow
consistently from the
northeast, especially during the summer - these are called the
trade winds and typically
lead to clouds and rain on the eastern sides of the island
19. (windward) with dry, stable air
sinking along the western side (leeward).
17
During the winter, migratory mid-latitude storms interrupt the
subtropical trade
winds and result in atmospheric flow from the south/southwest.
These are called Kona
winds and bring widespread precipitation to much of the island.
Sea and land breezes can occur on sheltered sections of leeward
coasts, such as
around Kona in Hawai'i. These winds are driven by land-sea
temperature interactions.
During the day, the land heats up and a sea breeze underneath
the trade wind inversion
takes place. This all leads to belt of persistent clouds and
rainfall on the mountain slopes
above Kona.
This zone is home to the farms that produce world-famous
Kona coffee. Uplift is
enhanced in the afternoons when the sun warms these slopes.
Strong trade winds and
intense heating during the summer also increase lifting, clouds,
and rainfall on the Kona
slopes. As a result, this is the only area in Hawaiʻi with an
afternoon rainfall peak, and
with more rain in the summer than other seasons (see mean
monthly rainfall at Kona
20. station Honaunau, below). You will see this belt of precipitation
in the geovisualization
game.
18
Rainfall Patterns and Rain shadows
Over the ocean near Hawaii, rainfall averages between 25 and
30 inches a year.
The islands receive as much as 15 times that amount in some
places and less than one
third of it in others. This is caused mainly by orographic or
mountain rains, which form
within the moist trade wind air as it moves from the sea over the
steep and high terrain of
the islands. Over the lower islands, the average rainfall
distribution resembles closely the
topographic contours. Amounts are greatest over upper slopes
and crests and least in the
leeward lowlands. On the higher mountains, the belt of
maximum rainfall lies between
2,000 to 3,000 feet and amounts decrease rapidly with further
elevation. As a result, the
highest slopes are relatively dry.
Another source of rainfall is the towering cumulus clouds that
build up over the
mountains and interiors on sunny calm afternoons. Although
such convective showers
may be intense, they are usually brief and localized.
Hawaii's mountains significantly influence every aspect of its
weather and
21. climate. The endless variety of peaks, valleys, ridges, and broad
slopes gives Hawaii a
climate that is different from the surrounding ocean, as well as
a climatic variety within
the islands. These climatic differences would not exist if the
islands were flat and the
same size.
The mountains obstruct, deflect, and accelerate the flow of air.
When warm, moist
air rises over windward coasts and slopes, clouds and rainfall
are much greater than over
the open sea. Leeward areas, where the air descends, tend to be
sunny and dry. In places
sheltered by terrain, local air movements are significantly
different from winds in
exposed localities. Since temperature decreases with elevation
by about 3 degrees per
thousand feet, Hawaii's mountains, which extend from sea level
to nearly 14,000 feet,
contain a climatic range from the tropic to the sub-Arctic.
This is a view looking north, where the eastern side is on the
right. The trade winds are
forced up and over a topographical barrier. The windward side
will be cloudy and wet as
air ascends, cools, and reaches the dew point (cloud formation
occurs) The lee side will
be warmer and drier as the air descends – and this is called the
rainshadow.
19
22. The image on the next page is famous for its portrayal of the
dramatic differences
in rainfall on the eastern (right) and western (left) sides of
Kohala volcano on the Big
Island. Moist trade winds encounter Kohala’s north-east facing
side and are forced to
rise. Rising air expands and cools due to adiabatic processes.
The cooling results in
condensation, cloud formation, and lots of rain. However, when
this air starts descending
on the southwestern side, it warms. The opposite happens.
Warming leads to cloud
evaporation and much less rainfall. The effect is clearly
dramatic in this image taken
from the Space Shuttle.
You can also see differences in the development of river
valleys. Both sides of
Kohala volcano are pretty much the same age. Its shield-
building stage ended about
250,000 years ago. Since then, only small volcanic eruptions
have occurred, such as the
cinder cones you can see along the summit. The valley cutting
that you see on the
northeast-facing side have occurred in the last quarter mission
years. However, its only
been wet enough to do this on that windward side of Kohala. It
is the rainfall that
concentrates in the stream that cuts the river valleys.
https://eol.jsc.nasa.gov/SearchPhotos/photo.pl?mission=STS051
&roll=102&frame=83
23. 20
The image above shows you a mean monthly precipitation at
two weather stations on the
windward side of Mauna Loa and on the leeward side. Please
focus on the vertical scale.
The amount of precipitation is a lot lower on the leeward side.
The station on the leeward
side is actually in one of the wetter locations on the western
side of the Big island. It is
much drier a bit to the north.
Trade Wind Inversions
The image below shows the latitudes between the equator and
just north of
Hawaii at the subtropical high (on the right). Hawaii is between.
All the basic
presentations about the Earth’s general circulation systems
show this circulation cell
(trade winds converge on the equator as the red lines and then
return as the dark blue line
to the subtropical high) called the Hadley Cell.
21
However, reality is more complicated. The air starts to
descend in the latitudes of
24. Hawaii, but it just down not reach the surface. It typically
reaches an elevation that
ranges from 1800 to 2400 meters (6000 to 8000 feet). Then, this
descending air creates a
TRADE WIND INVERSION.
What is the significance of the trade wind inversion? An
inversion is where
temperature begins to increase with elevation. The normal
condition is the reverse, and
that’s why its called an “inversion”. Increases in temperature
with height is not at all
conducive to rainfall. The moist-warm trade winds reach this
inversion, and the clouds
evaporate as the air warms up (as the air is pushed up slope).
Thus, forests stop suddenly,
and the vegetation comes scrub and then quickly desert-like,
because of the great
reduction in rainfall.
The below image shows the Trade Wind Inversion's influence
on the temperature
with height, in this diagram over Maui’s Haleakala volcano.
What this means is that the
orographic effect of cloud formation and the associated rainfall
is often STOPPED at the
Trade Wind Inversion, capping any clouds or precipitation that
would occur.
Biogeography
Biogeographers focus on plant and animal distributions – what
controls them and
what might happen in the future given what we know about the
past. There are a great
many factors that influence plants and where they grow. These
25. controls are typically
broken into abiotic factors (e.g. temperature limits,
precipitation limits, availability of
nutrients) and biotic factors (e,g, how species disperse,
competition, predation, parasites
& pathogens, mutualism such as symbiosis between fungi and
algae in a lichen).
At the scale of the Big Island and the LANDSAT composite
overlay on the
topography of the geovisualization video game, there are two
patterns that you will study
in this lab. One of them is the upper treeline of the rainforest,
and the other is plant
succession after the disturbance of a new lava flow destroying
the previous vegetation.
In mountain ranges in the mid-latitudes and at the highest
latitudes, treeline is
often controlled by temperature. If there is not enough of a
growing system with warm
enough temperatures, then trees cannot grow. In mountains,
treeline can also be
controlled by snow cover that lasts too much of the year to
allow trees to grow. However,
the upper treeline on the Big Island is not controlled by
temperature or snow cover. It is
controlled by precipitation.
22
In this lab, you will explore the trade wind inversion and its
impact on the
vegetation – basically where you see a browning of the
vegetation is the inversion base,
26. and you will measure its position at different locations on the
Big Island. Just take a look
at this Landsat composite view of the southeastern slopes of
Mauna Loa. The elevation of
the dashed line (average position of the trade wind inversion is
what you will investigate.
The Big Island is famous in biogeography as a place to study
rates of plant
succession. The idea is that a disturbance takes place (e.g. a
glacier obliterates previous
plant life, a fire burns an area, field of crops is abandoned). In
the case of the Big Island,
an entirely new earth’s surface is formed by basalt lava flows.
The Big Island is famous,
because the U.S. Geological Survey has determined the ages of
these lava flows using
radiocarbon dating of charcoal dug out from underneath the
flows. This allows plant
geographers to study how long it takes plants to re-establish
themselves.
23
When you consider the great climate variability across the Big
Island, Hawaii
becomes a perfect setting to understand how orographic rainfall
and rainshadow effects
(amount of precipitation) influences how fast succession occurs.
27. The Big Island’s plant
cover ranges from tropical rainforest on the eastern sides of the
island to desert scrub
vegetation on the rainshadow side.
In the diagram below, you can see side-by-side the area with
young lava flows
(less than a few thousand years) and the tremendous moisture
variability from very wet
(dark blue) to very dry (yellow).
24
STAGE B: EXPLORING THE BIG ISLAND THROUGH
OBSERVATION
Before you go any further, you need to get to know the five
main
volcanoes of the Big Island of Hawai’i. Just memorize them. It
will
make it so much easier for you in following the lab questions,
and when
you are in Hawai’i exploring in person.
Start by looking at the top map showing the extent of these
volcanoes (and their
lava flows), and then recognize them in the context of the
surface winds.
28. 25
Stage B Exploration: Making some basic observations related
to physical geography of the Big Island of Hawai’i
Stage B tasks you with exploring what this lab is about by
answering questions about
different aspects of the Big Island’s physical geography.
! Question B1: Volcano basics
! Questions B2 and B3: Rainfall and dew point patterns
! Question B3: Geomorphology processes changing volcanoes
! Question B4: Limits to Tree Growth
Question B1: Matching – select the best match between the
location and the volcanic
feature (or the basalt flow source).
NOTE: There are a big pool of these questions, and so the
instructions here apply
for all of the potential questions.
You are given geographic coordinates scattered around the
Island of Hawai’i. Use
Fast Travel in the geovisualization to travel to that location.
If the location is a volcanic feature that is not a lava flow (e.g.
caldera made by
29. collapse of a volcano into an emptied magma chamber, crater
made by the force of a
volcanic eruption (surrounded by cinder or lava), a pit crater
made by collapse into a
void, cinder cone made by lava reaching the surface in the form
of pieces called cinder
and dropping back down in the shape of a cone), then the
correct match will be the
correct name of the feature and an estimate of the height (e.g. of
the cinder cone) or the
depth (e.g. of the caldera) using the elevation data you see in
the geovisualization.
If the location is a basalt lava flow, then the best match
will be the volcano that is
the source of the lava flow. Just follow the lava flow uphill and
when you can’t see it
anymore – that’s the source. It will be one of the five big shield
volcanoes.
26
EXAMPLE QUESTION B1. Select the best match between the
location and the
volcanic feature (or the basalt flow source). If the feature has
positive relief (goes
up), then estimate its height using the highest elevation at the
top and the lowest
elevation around its base. If the feature is a negative relief
(depression), then
measure the highest location at the edge and the lowest
30. education at the bottom to
estimate the maximum depth.
Locations
(that will be
randomized)
Screenshots with camera angle pulled back
19.8481,
-155.9460
Note: The avatar is on the black lava flow near the ocean
19.8141,
-155.4724
Note: The avatar is on a small hill near the summit of Mauna
Kea, lower
right view
27
19.4315,
-155.6086
Note: the avatar is standing in a caldera near the summit of
31. Mauna Loa.
The main caldera at the summit is in the background of the
screenshot.
The color of the lava is quite dark. Thus, the screenshot was
brightened
up a lot so that some of the features would show up better in
this PDF
format.
19.3416,
-155.8821
Note: the avatar is standing on a basalt flow near the ocean. The
basalt
flow is on the west side of Mauna Loa. If you hop the avatar up
the
volcano, you will quickly be able to determine that Mauna Loa
is the
source.
28
Below, you will find the correct matches in this example
question, in the same order
as presented in the screenshots above. As long as you have a
basic understanding of
volcanic features (e.g. basalt lava flow, cinder cone, caldera),
and you go to the
32. location in the game and move up the lava flow to its source –
the hope is that this
question is not difficult.
Locations (that will
be randomized)
Correct Matches
for those
locations (but
will be
randomized by
canvas)
Game Screenshot of the Fast Travel
Location
19.8481, -155.9460 Hualalai Volcano Hualalai Volcano erupted
during 1800-
1801 to produce the lava flow you
investigated. It emerged from 5 fissures
along the rift zone on the northwest side of
this shield volcano. The lava flow made it
to the ocean and buried Hawaiian villages
along the way.
19.8141, -155.4724
Cinder Cone (that
does not quite
have a cinder
cone shape in the
game) about 90
m tall
33. This cinder cone is near the top of Mauna
Kea. The cinder cone is about 90 m in
height.
19.4315, -155.6086
Caldera, about 90
m deep
Lua Hou is a called a crater, but its really a
caldera made when the top of a volcano
collapses. Craters are smaller, and they can
be pit craters (made by collapse) or craters
made by the force of an eruption.
19.3416, -155.8821
Mauna Loa This 1950 basalt lava flow was part of an
eruption that lasted 3 weeks. The volume of
lava in this eruption was about the same as
what gets erupted out of Kilauea in an
active phase in about 3-4 years.
29
Questions B2 and B3: Patterns of Precipitation and Humidity
(Dew point) on the
Big Island
IDEA OF Question B2: You are supplied with different
locations around the Big
34. Island of Hawai’i. You Fast Travel to these locations in the
geovisualization, and
you match the location to the explanation of the precipitation
pattern that you see.
SET UP INFORMATION FOR THE FIRST QUESTION:
Northeast trade winds prevail most (70%) of the year
and generally blow 10-20
mph. Exceptionally strong and gusty trade winds occur when the
sub-tropical high of the
central North Pacific Ocean intensifies. These can reach 40-60
mph in the coastal zone of
Hawaii, sometimes for several days at a time.
When the trade winds encounter the volcanoes of the Big Island,
they rise. Rising
air cools, condenses into clouds, and rain is enhanced in by this
“orographic” (mountain)
effect. Then, when air descends on the lee side of the volcanoes,
the air warms as it
descends adiabatically. Hence, the clouds evaporate and the air
has a lower relative
humidity.
30
The orographic effect is capped on the Big Island by the Trade
Wind Inversion (TWI).
35. Descending air in the Hadley circulation cell does not reach the
ground at the latitude of
Hawaii, but it gets close to the surface. The elevation of this
TWI varies daily and
seasonally, but you can see its average position very clearly in
the geovisualization where
the rainfall and the dew points drop off dramatically.
There is yet a fourth pattern in the precipitation of the Big
Island, a summer
precipitation maximum on the Kona Coast on the western side
of Mauna Loa and
Hualalai volcanoes. These North and South Kona Districts on
the Island of Hawaiʻi have
a unique rainfall pattern. The west-facing slopes of Hualalai and
Mauna Loa are sheltered
from the trade winds. But, as air flows around the large
mountains, it curves back on the
leeward side and flows up these slopes, producing a belt of
persistent clouds and rain.
This area is home to the farms that produce world-famous Kona
coffee. Uplift is
enhanced in the afternoons when the sun warms these slopes.
Strong trade winds and
intense heating during the summer also increase lifting, clouds,
and rainfall on the Kona
slopes. As a result, this is the only area in Hawaiʻi with an
afternoon rainfall peak, and
31
36. with more rain in the summer than other seasons (see mean
monthly rainfall at Kona
station Honaunau, below and the map of Big Island winds
below).
So in total, there are four explanations of the pattern you see in
precipitation across the
Big Island of Hawai'i. They are:
1. Orographic effects of the northeasterly trade winds
2. Rainshadow effects on the lee sides of the volcanoes
3. Trade wind inversion capping the orographic effect at a
certain height
4. Land-sea interaction (afternoon sea breeze) and complex
wind patterns (curving
of winds around volcanoes) above Kona on the west side of the
island.
32
EXAMPLE QUESTION B2: You are given four different
geographic locations on
the Big Island that display a different aspect of precipitation
37. variations. Please
match the cause of the precipitation pattern that you see in the
geovisualization to
the location.
In Canvas, there are a pool of questions that have these same
causes. However, you
will be supplied different locations to visit in the
geovisualization via fast travel. You
will see the precipitation in the mean annual precipitation
surface in the game.
Please understand that canvas will scramble the match, but the
correct answers are
displayed below for you to investigate in the geovisualization.
Just click on the
precipitation to see the precipitation variations explained in the
example.
Location Cause
20.1543 -155.7373 The easterly trade winds are forced to rise
when they encounter
the Hawaiian volcanoes. This is called an orographic effect,
where the rising air cools, condenses, forms clouds and
enhances
rainfall through this orographic (mountain forced) uplift.
20.1130 -155.8113 Rainshadows are caused by descending air
in the lee of a
mountain range (or large volcano). The trade winds reach the
top
of the Hawaiian volcanoes and descend on their west side.
Descending air is compressed, and this compression causes
warming at a rate of 10˚C per 1000 meters. This is called
adiabatic warning. Warming means that clouds can evaporate
and this leads to a reduced amount of precipitation called a
38. rainshadow.
19.8309 -155.4117 The Trade Wind Inversion is a key reason
why precipitation
amounts are so low above 2300 m on the Big Island. The trade
winds and their moist marine air dominate below this altitude.
However, above 2300 m, the air is descending as part of the
Hadley Cell. The descending air starts at the top of the
troposphere and has low amounts of water vapor and hence low
precipitation amounts.
19.5685 -155.9013 During summer, the North and South Kona
Districts of the Big
Island have belt of precipitation on the west-facing slopes of
Hualalai and Mauna Loa. This area is sheltered from the trade
winds, except as air wraps around these volcanoes, it curves
back to the island and flows up slopes. Air flowing up slope
cools, condenses and produces a belt of persistent clouds and
rain. This uplift is enhanced in the summer afternoon as
morning
sun heats up the slopes, producing a sea breeze enhancement to
the uplift.
33
The screenshots from these locations in the geovisualization are
shown below with
the camera angle pulled back.
Location Cause
20.1543 -
155.7373
39. Trade Wind
Orographic Effect
20.1130 -
155.8113
Rainshadow of the
trade winds
19.8309 -
155.4117
Trade wind
inversion
19.5685 -
155.9013
Belt of
precipitation on
the west-facing
slopes of Hualalai
and Mauna Loa
34
SET UP INFORMATION FOR THE NEXT QUESTION: Dew
point is the
temperature at which condensation occurs. You see dew on the
ground when the air
temperature right next to the surface cools to the point where
40. dew forms. You see that
temperature visually when you look at the flat bottom of a
cumulus cloud, because the air
was lifted and cooled adiabatically to that dew point. Dew
point is a much more
understandable measure of the amount of water vapor (gaseous
water) in the air than
grams per cubic centimeters. In fact, news broadcasts often
present dew point as an index
of misery in the summer, but there is no official “muggy meter”
or “misery index”. It all
depends on you and what you like.
There is, however, an official heat index, and there is a
calculator that allows you to
use air temperature and dew point to calculate that heat index:
https://www.wpc.ncep.noaa.gov/html/heatindex.shtml
Or, if you wish, you can use this formula or refer to the graphic
below
Heat Index = -42.379 + 2.04901523T + 10.14333127R -
0.22475541TR - 6.83783 x 10-3T2 -
5.481717 x 10-2R2 + 1.22874 x 10-3T2R + 8.5282 x 10-4TR2 -
1.99 x 10-6T2R2T - air
temperature (F)R - relative humidity (percentage)
You can also just read the heat index from this NOAA table:
https://www.weather.gov/media/jetstream/global/heatindex_char
t_dp.pdf
The chart looks like this, but you’ll need the higher resolution
to see anything:
41. 35
The dew points of the Big Island are influenced by the same
thing as the rainfall. The
trade winds below the trade wind inversion contain a lot of
tropical water vapor. Above
the trade wind inversion, however, the air is bone dry because it
has been coming from
the top of the troposphere, where there is a lot less water vapor.
The moist trade winds
mix with the dry air right around the trade wind inversion,
where there is a very big
gradient.
This next question asks you to visit two different locations on
the Big Island that have
experienced the same temperatures on the same day. We
researched this using weather
station data, as well as data gathered from different scientific
research projects.
What you will do in this next question is simply calculate the
HEAT INDEX for these
two different locations. You will obtain the dew point
information from the
geovisualization and then use either (i) the website, (ii) the
formula, or (iii) the dew point
graphic on the previous page to answer the question.
EXAMPLE QUESTION A3: Go to 19.4201 -155.2884
coordinates where at 10 am on
May 15, the temperature was 84˚ F. Write down the dew point
that you see in the
geovisualization. Then, go to 19.7595 -155.4561 coordinates
42. where at 2pm on May 15,
the temperature was 84˚ F. Write down the dew point that you
see in the
geovisualization. What’s the heat index for these two spots?
The example is provided below in one row. The second row
is for your
convenience when you answer the question.
Site Dew
point
Time Temp
˚F
Heat
Index
Site Dew
point
Time Temp
˚F
Heat
Index
Visitor
Center HVO
19.4201
-155.2884
55 ˚F 10 am 84 ˚F 83˚ F Onizuka
Astro Center
19.7595
-155.4561
43. 28 F 2 pm 84 F 81˚ F
36
Question B4: Geomorphology processes changing volcanoes
SET UP TO THIS QUESTION:
This question tasks you with analyzing the relationship between
rainfall and the
development of river valleys on the oldest of the volcanoes on
the Big Island, Kohala.
Kohala started to develop about a million years ago, building up
from the sea floor. It
probably reached sea level about a half-million years ago and
build its shield shape
between 0.5 and 0.25 million years ago. Kohala did have a few
small eruptions
afterwards, but its last known lava flow is 120,000 years ago.
There are lots of different geomorphology processes that alter
volcanic features,
and the major ones are discussed in the background section of
this PDF file. This
particular question focuses on the asymmetric development of
river valleys.
The side of Kohala facing the trade winds has developed deep
valleys with
Honokane Nui being the deepest one. These valleys have eroded
44. into the basic shield
shape of Kohala. In contrast, the leewards west-facing side has
only small river valleys
with the biggest being Honokoa Gulch.
Honokoa Gulch Honokane
Nui
You will be analyzing the differences in the depth of incision
(downward erosion)
of the biggest river valleys on the east-facing and west-facing
sides of Kohala, and you
will also be analyzing the amount of precipitation falling the
different sides.
EXAMPLE QUESTION:
Using Fast Travel, take your avatar to the Honokane
Nui valley of the Kohala
volcano (20.1967, -155.7204) and walk up the river valley
towards the summit caldera
Kohala volcano (20.0803, -155.7139). When the valley splits
into two tributaries, take
the split to the left (east fork) as you are walking up.
37
This is a screenshot of the avatar standing on the ridge above
the Honokane Nui Valley
Note the elevation is 215 m . Since the valley bottom is 35 m,
the depth at this location is
45. 180 m. NOTE: the precipitation should be read at the bottom of
the river valley.
This is a screenshot of the avatar standing in and just above
Honokoa Gulch a bit upslope
from the ocean. The darker shading you see is the Honokoa
Gulch. The slight bend in the
elevation where the avatar is standing on the right frame is
where you will measure the
river elevation and also the precipitation. Then, just hop the
rabbit up (see left frame) and
measure the elevation. The difference is the depth of the river at
this spot.
38
Then, go to the Honokoa Gulch (20.0524, -155.8386)
on the western rainshadow
side of Kohala, and follow this gulch up towards the caldera of
Kohala volcano.
These are the two largest river valleys on the east-
facing (Honokane Nui) and
west-facing sides (Honokoa Gulch ) of Kohala volcano.
Part 1: What is the difference (in meters) in the depth of these
river valleys at an
elevation of 35 m above sea level? Just have your avatar go up
to the side of each river
and note the elevation difference between the Kohala shield
46. volcano surface above and
the river below.
Part 2: In the game, examine the mean annual precipitation
amounts at an
elevation of 35 m on the Honokoa Gulch and Honokane Nui
streams. What is the
difference (in millimeters of precipitation) at these elevations?
Part 3: Keep an eye on the depths of these river valleys and the
precipitation
amounts in the upper parts of their drainage. Based on your
observations in question B2
and also your observations in this question, what is the reason
for the differences you
observed in parts 1 and 2.
Note 1: Measure the mean annual precipitation at the river
bottom locations, not on the
ridges above. Round precipitation to the nearest 100 mm above
1000 mm, and round
to the nearest 10 mm below 1000 mm.
Note 2: Do your best to locate yourself on the ridge above the
river valley on the east
side. Write down that elevation and subtract the river elevation
to ESTIMATE THE
DEPTH of the river valley. The depth measurements will be
tricky. The 30 m pixel
size limits precision. However, Google Earth is not any better.
It also uses 30 m
resolutions, but it just has a smoothing algorithm that guesses
between the center of
the 30 m cells. The ‘bottom line” is that you cannot be precise.
Do not worry about
trying to get too exact of a measurement. Just get close and you
will get the correct
47. answer.
CORRECT ANSWER:
Part 1: At an elevation of 35 m, the depth of the Honokane
Nui Valley is about 180 m,
based on the 215 m elevation of the ridge above the river valley.
In contrast, at an
elevation of 35 m, the depth of the western Honokoa Gulch is
just 60 m, with the area
above the valley bottom being at 95 m.
Part 2: Precipitation on the windward side facing the trade
winds is an order of
magnitude greater (2300 mm) as opposed to the 240 mm on the
rainshadow side of
Kohala Volcano.
The likely reason for both differences is the rainshadow
effect on the western slope of
Kohala volcano.
INCORRECT ANSWERS could have incorrect depths in part 1,
incorrect mean annual
precipitation amounts in part 2, and/or an incorrect reason in
part 3. Please realize that
when there are incorrect depths or precipitation amounts, the
differences will not be
trivial—so you should not worry about the exact locations
where you make the
measurement of depth or precipitation.
39
48. Question B5: Limits to tree growth on the east slope of Mauna
Loa
In this question, you will explore the
trade wind inversion and its impact on
Hawaiian biogeography, specially trees.
Just take a look at this Landsat
composite view of the southeastern
slopes of Mauna Loa. The elevation of
the dashed line (average position of the
trade wind inversion) is what you will
investigate.
In the geovisualization, using the
LANDSAT composite overlay, you will
be directed to specific locations in the
videogame. These locations are near
the boundary between the dark green
and the brown above. The dark green is
forest. The dark brown is a mix of
shrubs and dwarf trees, and above that
is just shrubs. This change from forest
to non-forest above is called the
treeline. In this case, it coincides with
the trade wind inversion.
Landsat Composite image highlighting the
treeline between the Kaʻū and Kapapala
Forest Reserves on the southeast side of
Mauna Loa
QUESTION INSTRUCTIONS: Using Fast Travel, please visit in
the geovisualization at
the indicated locations. You will not be sent to the exact
49. location of the treeline. Part of
the question involves you looking for the highest elevation of
the dark green trees, using
the Landsat Composite layer. These are a couple of examples.
There will be a complication -- that lava flows have
periodically wiped out the
vegetation, and then the trees gradually re-establish themselves.
Thus, you are to walk to
the highest dark green nearby. Write down the elevation, and
also switch to precipitation
and write down those values.
40
Then, have your avatar travel directly upslope of this
treeline about 500 m higher
and write down the mean annual precipitation (MAP 500m+).
Then, calculate an average
(mean) and range of all data you collected
QUESTION: Part 1: What is your mean and range for the
trade wind
inversion treeline on the southeastern slopes of Mauna Loa – in
terms of its
elevation and mean annual precipitation (MAP). Round off to
the nearest 100.
Part 2: 500 m above the treeline locations, how much has
the average
precipitation declined from the treeline? Round off to the
nearest 100.
50. ANSWER: The treeline closest to the indicated coordinates
averages 2000 m (range
1900-2000 mm) with a mean annual precipitation averaging
1900 mm (range 1750-
2100). The precipitation drops off by an average of 300 mm just
500 meters upslope from
treeline.
You can use this table to take notes on the locations in this
practice question, and
you can also use this table to answer the question you will get
in canvas.
Lat/Long you are sent to Treeline
Elevation
nearby in
meters
MAP- at
treeline in
mm
Elev 500 m
higher
MAP 500 m
higher
Average
Average rounded off to
nearest 100
51. Range
THIS IS AN EXAMPLE OF ONE OF THE SITES BELOW, AT
TREELINE AND 500
M ABOVE TREELINE
41
EXPLANATION:
Lat/Long you are sent to Treeline
Elevation
nearby in
meters
MAP- at
treeline in
mm
Elev 500 m
higher
MAP 500 m
higher
19.3766 -155.4776 1900 1200 2400 900
19.3772 -155.4928 2100 1100 2600 800
19.3171 -155.5243 2000 1100 2500 800
19.2965 -155.5378 2000 1100 2500 800
19.2686 -155.5672 2000 1100 2500 800
52. Average 2000 1120 2500 820
Average rounded off to
nearest 100
2000 1100 2500 800
Range 1900-2100 1100-1200 2400-2600 800-900
THIS IS ANOTHER EXAMPLE OF ONE OF THE SITES IN
THE LIST ABOVE, AT
TREELINE AND 500 M ABOVE TREELINE
INCORRECT ANSWERS: Please do not worry if what you
wrote down differs a bit
from what I wrote down in making this example. What you
interpreted as the treeline
location will be a little bit different from someone else (like the
person making this key).
This is the reality of science. Even if you were in the field,
looking at the treeline, it
would be hard for 10 scientists to agree on the precise location.
This is because trees
become more scattered at treeline. However, when you average
five measurements
together, and then when you round off that average to the
nearest 100 – simply pick the
answer that is closest to what you observed and calculated. The
incorrect answers
will have some piece of information that is quite far off making
it obviously
incorrect in this 100-level course.
53. 42
STAGE C Investigation and more detailed analysis: Exploring
the
physical geography of the Big Island Hawai’i
Components of the science of Physical Geography
This section covers 5 of the areas of physical geography
portrayed in this diagram.
Task 1: Focuses on the geological materials that make up the
Big Island by exploring
differences in Hawaiian volcanoes (geology).
Task 2: Deals with an aspect of how long-term climatic changes
have altered the physical
geography of the Big Island through glaciations during glacial
cycles (hydrology and
landforms).
Task 3: Goes into some detail on adiabatic processes and their
importance in orographic
rainfall and the rainshadow effect – focusing on Kohala
Volcano (climate).
Task 4. Deals with the elevation of the Trade Wind Inversion
that caps the rainfall on
the Big Island. You study this cap in rainfall through analyzing
dew points (a measure of
the amount of moisture in the atmosphere) and how they change
54. at different elevations
(climate).
Task 5: Focuses on how volcanic and climatic processes
influence establishment of
plants on the Big Island on lava flows of different ages
(biogeography).
43
The Fast Travel default locations in the geovisualization takse
you to the tops of the ‘big
five’ volcanoes seen in the map above.
C1: Differences in volcanic development of volcanoes on the
Big Island
This task asks you to wander around the volcanoes of Hawai’i
in the geovisualization and
observe differences in their volcanic development using the
Landsat composite image.
The background knowledge you will need to make observations
are in the volcanoes
GPH 111 lecture (linked on the first page of this PDF file), as
well as background
information presented in section 3 of this PDF file.
Here are possible questions that you might be given in canvas
that relate to this task. The
questions are presented in a table format that allows you to take
notes if you wish (e.g.
55. elevation of summits, latitude and longitude location of features
you see, other
observations) during your geovisualization exploration. The
question that you receive in
canvas will likely task you to visit particular locations in the
geovisualization in order to
contextualize the question.
Possible question in task 1 Notes made during geovisualization
exploration
Which volcano has the basalt flow that
has the biggest elevation range (from top
to bottom)?
What volcanoes look visually to be the
most active, based on the overall darkness
of the volcano surface?
Which volcanoes have historic lava flows,
as evidenced by dark black lava?
Which volcanoes have large summit
calderas due to collapse into emptied
magma chambers? Or which ones do not
and are in the post-shield stage?
44
56. Which volcanoes have abundant cinder
cones scattered around near their
summits?
What volcanoes have relatively steeper
slopes capping the volcano? Relatively
flatter slopes around the summit of the
volcano?
Which volcanoes have rift zones where
clear evidence of lava can be seen in the
game flowing down from these rift zones?
Which volcanoes have old-enough
surfaces to be incised by stream systems?
(Hint: Look carefully around the
coastlines, because the river valleys start
to form first close to the coast-line and
then grow headward towards the volcano
summit)
Again, if these terms are confusing, please reread the
background information material
presented earlier in this PDF file or review the GPH 111 lecture
on volcanoes linked to
the first page of this PDF file.
EXAMPLE QUESTION: Two Questions similar or identical to
those in the list
above will be delivered to you randomly from a bank of the
57. above questions, where
even the same question could have a different set of correct and
incorrect multiple
choice answers. The first question will be about the stage of
the volcano and the
second question will be similar to the list above.
Question Choices Feedback explaining the answer
What volcanoes are in the
shield stage? A stage between
shield and post-shield? The
post-shield stage? Or in the
Rejuvenated stage?
There are
different
wordings in the
bank for this
question.
Since there are 5 volcanoes and only
4 multiple-choice questions,
volcanoes that could BOTH answer
a question are possible. Please
realize that these “both correct”
possibilities have been eliminated
from the question bank.
Look around the tops of the 5
big volcanoes. Which of the
listed volcanoes has the
lowest slopes (flattest terrain)
around its summit?
Please look at the next page
for the sorts of views you can
explore in the
58. geovisualization to help
answer this question.
Mauna Kea
Kohala
Kilauea
Mauna Loa
Mauna Kea has fairly steep upper
parts, which is characteristic of post-
shield volcanic activity. Mauna Loa
and Kohala have lower slopes than
Mauna Kea, but there’s not doubt
that the area around the summit of
Kilauea has the lowest slopes
(smallest elevation change). This
very low slope is characteristic of a
shield volcano that is in its building
stage.
45
The screenshots below would be the sorts of observations you
would make to help
answer this question.
59. Kilauea’s
summit is the
flattest (lowest
slopes). It does
not even have
the shape of a
shield volcano,
like Mauna
Loa below.
Mauna Loa has
low slopes, but
nowhere near
as flat as
Kilauea.
If you look at
Kohala, it has
a shape with
summit slopes
similar to
Mauna Loa.
Hualalai has a
pretty steep
summit,
almost as steep
as Mauna Kea.
46
60. Stage C2: Figure out how long-term climatic changes have
altered the physical
geography of the Big Island through glaciations during glacial
cycles.
THE QUESTION: What is your estimate for the maximum
thickness of the Makanaka
Ice Cap of Mauna Kea at this location (latitude and longitude)
in the geovisualization?
SETUP FOR THE QUESTION:
Mauna Kea is an old-enough volcano to have been glaciated at
least three times in the last
150,000 years. This is what the latest ice cap might have looked
like about 15,000 years
ago when the ice was melting away. Research done by
Professor Dorn of ASU and
colleagues has shown that the mountain was glaciated about
150,000 years ago, 65,000
years ago, and the last big glacial pulse called Makanaka was
about 21,000 years ago:
http://www.public.asu.edu/~atrid/NGRE91.pdf
Image created from Google Earth scenes by ASU student Alexis
Ruiz
Determining the thickness of ancient glacial ice may seem a bit
esoteric, but it is what
physical geographers do in order to reconstruct past climates
and understand how Earth
responds to climate change. While climate modeling can try to
predict the future, many
61. physical geographers think that understanding past conditions is
the best way to
understand future possibilities.
Where there are big mountain ranges with alpine glaciers, we
use trimlines.
47
Ice flow can leave behind a line on the side of a glacial valley
and that allows a good
estimate for ice thickness. Even when the glacier has
completely disappeared such as in
Yosemite, it’s possible to make reasonable estimates, as
illustrated in this National Park
Service reconstruction.
Trimlines do not work well for Mauna Kea. The reason is that
the rock type is not strong
enough to retain an erosional line. Cinder cones form the
topography that sometimes
stuck out above the ice cap, and these pieces simply keep
moving down the slope and
erasing the evidence. This USGS photograph shows glacial
deposits (till) underneath a
40,000 year old lava flow, glacial deposits on top of small
cinder cones, and also glacial
deposits left by ice that was forced to split and go around tall
cinder cones. The lighter
62. color of the till is due to accumulated silica glaze rock coatings.
48
Split flow around and between tall cinder cones certainly did
not look like the split
glacial flow on Mount Rainier, but this photography may give
you the idea.
The graphic below shows the USGS aerial photography (on the
right) with splitting
glacial flow around and between cinder cones, and the left is
what this location looks like
in the geovisualization with the camera angle pulled up high
well above the avatar
(yellow arrow) standing on a cinder cone.
The illustration below shows split flow in the game (left) and
in a space shuttle view
(right) where the yellow arrows are in the same place with a
down-glacier direction.
49
63. EXAMPLE QUESTION: What is your estimate for the
maximum thickness (in
meters) of the Makanaka Ice Cap of Mauna Kea at this location
(19.8417,
-155.4295) in the geovisualization?
HOW TO ANSWER THIS QUESTION:
Step 1: Use fast travel to go to the location, which
should be on top of a cinder
cone surrounded by the split flow. This is a screenshot of this
example location:
Step 2: Write down the elevation of the top of the cinder cone.
The ice cap’s top was had
to be below the elevation of the cinder cone, or there would be
evidence on top.
Topography up glacier of cinder cone: Top of the Cinder
Cone:
Step 3: Find the height of the cinder cone above the
topography that is UP
GLACIER of the cinder cone. The glacier would have been
flowing downhill, so just
jump off the cinder cone top and do the subtraction. That is the
answer to the question.
ANSWER: The ice cap at this location was less than the 120 m
height of the cinder cone
top above the topography on the up-glacier side of the cinder
cone.
EXPLANATION: I wrote down an elevation of 3785
64. for the unglaciated top of
the cinder cone at 19.8417, -155.4295 and an elevation of 3665
for the glaciated upside
of the cinder cone at 19.8407, -155.4342. Thus, the thickness
of the ice at this point
would have been less than 120 m (3785-3665 = 120).
50
SECOND RELATED QUESTION ON GLACIAL THICKNESS:
Determine the
average of these thicknesses, and then use that average ice
thickness to calculate the
total volume of the ice cap that was on top of Mauna Kea about
21,0000 years ago.
Select the best answer in cubic meters.
INSTRUCTIONS TO DO AN EXAMPLE QUESTION.
How to answer this question:
1. You will be supplied with ice cap thickness values for this
question, but you will
need to calculate the average from those values. For example,
other
measurements of Mauna Kea ice cap thickness taken at
locations different from
yours in the previous problem were: 50 m, 60 m, 120 m, 90 m,
60m.
The average ice thickness is around 76m.
2. S.C. Porter of the University of Washington measured the
65. area of the Makanaka
Ice cap to be about 70 km2. You have to multiply square
kilometers by a million
to obtain square meters of area.
Volume = 76m * 70,000,000m2
3. When you multiply area (square meters) by thickness
(meters), you get a
volume in cubic meters. The answer in this example is a lot of
zeroes. Be
careful in adding the commas to separate them out.
Volume = 5,320,000,000 cubic meters
ANSWER AND EXPLANATION: The format of the answer
could be in numbers of
words, like 5.3 billion cubic meters. It could be in the format
of a number like
5,320,000,000. But the correct answer has to follow the
instructions of cubic meters.
How can you relate? The photograph below is of Mount Rainier
near Seattle (along with
an ASU student). The total volume of ice on this volcano is
about 2.9 billion cubic meters
today. That means that the volume of the Mauna Kea ice cap
was almost double Rainier.
51
66. C3: Trade Winds, Orographic Rainfall and Rainshadow Effects
Easterly winds
encounter the
topography of
Hawai’i and the
air is forced to
rise. As it rises,
it cools. Clouds
form (lifting
condensation
level or LCL).
There’s rain as a
result.
However, on the
lee (western)
side, the air only
warms from
compression.
Thus, there is a
lot less rain on
the rainshadow
(lee or western)
side.
All of the questions in the pool will give you a starti ng
temperature and the dew
point (temperature when clouds begin to form). For this
example problem, use a
typical temperature of 25˚C for the eastern coastline of the Big
Island. Use a dew point
of 15˚ C. The dry adiabatic rate of cooling from just uplift is
10˚ C per 1000 meters.
67. The wet (or moist) adiabatic lapse rate is not as drastic of a
temperature change. In
Hawaii, it is typically 5˚C per 1000 m. This slower rate of
cooling is due to the release of
energy (latent heat) when water vapor is turned into liquid (in
the form of cloud droplets).
EXAMPLE QUESTION AND PROBLEM:
Follow a parcel of air from sea level, up and over Kohala.
Calculate the temperature
changes along the way every 500 meters. The correct answer
will have three parts:
(1) Calculate at what elevation the clouds start to form (lifting
condensation level).
(2) Determine out how much warmer the air temperature is at
the coast line on the
western side of Kohala than the sea level on the eastern side of
Kohala.
(3) In the geovisualization, determine the mean annual
precipitation (MAP) at the
given longitude and latitude locations as the parcel of air goes
up and then down
Kohala.
52
The following chart will help you take notes as you analyze
what happens to the air
parcel. Remember, the air goes east (right) to west (left), not
like you read.
68. ANSWER: Clouds start to form at about 1000 m. The air is
about 2.5˚C warmer on the
western side than the eastern side. Mean annual precipitation
goes from 2300 mm (0
m), to 2400 mm (500 m), to 4000 (1000 m), to 3300 (1500 m),
to 800 mm (1000 m on
the west side), to 400 mm (500 m on the west side), to 250 mm
(0 m) on the west side.
INCORRECT ANSWERS: The incorrect answers will not try to
fool you with answers
that are super close. The incorrect answers, instead, will catch
error of comprehension.
EXPLANATION OF THE ANSWER: The diagram above
illustrates what happens to the
temperature. The air rises and cools at the dry adiabatic lapse
rate (10˚ C per 1000 m and
that is 5˚ C per 500 m). Thus, the air reaches the 15˚C dew
point at 1000 m. From that
point, it cools at 2.5˚ C per 500 m and so its 12.5˚ C at the
summit at about 1500 m. Then,
it warms 15˚ C as its drops 1500 m. The rate of warming going
down is always 10˚
C/1000 m, because there’s only air compression going on (no
latent heat release).
You probably noted that the maximum mean annual
precipitation does NOT occur at
the highest elevation (as you might expect). It occurs as the air
is rising up towards the
high points of Kohala volcano. The reason has to do with the air
drying a bit because of
the influence of the trade wind inversion. [Descending air from
higher up in the
69. atmosphere mixes with the trade wind moisture and the amount
of water vapor drops a bit
The intense drop off in precipitation on the lee (west) side
is due to the
rainshadow effect of descending and warming air, just as the
increase in rainfall on
the eastern (windward) side is due to the uplift (orographic
effect) of the trade
winds.
53
C4: Understanding the Trade Wind Inversion through
Analyzing Dew
points
BACKGROUND FOR THE QUESTION IN TASK 4: The trade
wind inversion (TWI) is
a transition layer between moist marine air and much drier air
descending from the upper
level of the troposphere, associated with the Hadley Cell.
The trade winds underneath the TWI have very high dew
points, due to evaporation of
the tropical ocean around Hawaii. Turbulence in the lower par t
of the atmosphere is
common, along with cloud development. This turbulence leads
to mixing of some
moisture around the TWI. However, above this zone of mixing
is much drier air, and at
70. the elevations around the summits Mauna Loa and Mauna Kea,
the air flow is actually
part of the westerlies. This is an idealized diagram from Cecilia
Grindinger:
54
The diagram below from Grindinger is of a sounding up into
the atmosphere measuring
how air temperature and dew point change at different altitudes.
Note that the
temperature jumps just a little bit (from about 9˚C to about
13˚C, reading the horizontal
scale) at about 2300 m on this day and time. At the same
elevation, you can see a
remarkable drop in dew point from about 9˚C to about -15˚C.
These changes occur over a
vertical distance of just a few hundred meters.
The elevation of the TWI in these graphcs is portrayed at about
2200m, but this is a
generalization. It will vary in elevation at different locations
across the Big Island. Also,
keep in mind that the elevation of the TWI changes from day to
day and even within a
same day. The dew points that you see in the geovisualization
are an average annual
condition. Thus, when you visit the Big Island and observe the
effects, what you analyze
71. here could shift up and down a bit.
The question for this task asks you to identify the elevation of
the biggest dew point
gradient, using the information in the geovisualization. You
will be tasked with walking
down from the summit of either Hualalai, Mauna Loa, or Mauna
Kea and writing down
the dew points you observe at different elevations. Then, you
will identify the elevation
where you see the BIGGEST CHANGE in dew points.
55
EXAMPLE QUESTION: In a transect of dew points from the
summit of Mauna
Kea and walking north in the geovisualization, what 500 meters
of elevation change
had the LEAST change (lowest gradient) in dewpoint change?
Also, what is that
gradient measured in ˚F per 100 meters (˚F/100m)
EXAMPLE QUESTION INSTRUCTION: Fast travel to the
summit of Mauna Kea at
4236 m at 19.8230 -155.4696. Walk in a straight northern
direction from the summit
of Mauna Kea. Start at the summit, then go to 4000 m. Write
down the dew points you
see in the geovisualization every 500 meters (find the elevation
closest to every 500 m).
Then, just look at the data you’ve collected and identify the 500
meters in the elevation
72. profile where you see the biggest CHANGE (increase in dew
point) over an elevation
difference of 500 meters.
This table is for your convenience.
Summit Elevation: Summit dewpoint:
Elev 4000 3500 3000 2500 2000 1500 1000 500 35 m
in
game
but
treat
as 0m
Dew
point
Gradient
˚F/100m
NOTE: to calculate the gradient: Step (1) find the difference
(substraction) in dew points
between the elevations; step (2) divide by 5 (not 500), because
the units are ˚F change per
100 m. You can fill out the gradient row by starting on the
right cell, and it will be the
gradient from 500 m to 0 m (sea level). The next cell will be
1000 to 500 m and so forth.
NOTE: You might be doing the full elevation dew point transect
of a volcano. Or, in
some questions, you will be asked to only examine the dew
point between two different
73. elevations on the side of a volcano, READ THE QUESTION
CAREFULLY.
Landsat composite view from the top of Mauna Kea looking
north
56
Dew Point from the summit
Dew Point from 4000 m
Dew Point from 3000 m
Dew Point from 2000 m
57
Dew Point from 1000 m NOTE: the sea level dewpoint on this
transect is 66˚ F
74. QUESTION: In a transect of dew points from the summit of
Mauna Kea and
walking north in the geovisualization, what 500 meters of
elevation change had the
LEAST change (lowest gradient) in dewpoint change? Also,
what is that gradient
measured in ˚F per 100 meters (˚F/100m).
ANSWER: The lowest dew point gradient is 0.6˚F/100m, and it
is from 500 m to sea
level (35 m in the game, but treat as 0 in the gradient
calculations). The reason is that the
lowest parts of the atmosphere has been picking up water vapor
over a long stretch of
ocean surface. Thus, its reached its equilibrium and absorbed
what it can.
Please note that your question will be different in wording,
and so read it carefully.
Summit 4175: 12˚ F
Elev 4000 3500 3000 2500 2000 1500 1000 500 35 m
but
treat
as 0m
Dew
point
12˚ F 20˚ F 28˚ F 36˚ F 42˚ F 50˚ F 58˚ F 63˚ F 66˚ F
Gradient
˚F/100m
0
from
75. 4175
to
4000
1.6 1.6 1.6 1.2 1.6 1.6 1 0.6
58
Task 5: How volcanic and climatic processes influence the
biogeography of plants
on the Big Island.
One of the most important basic concepts in the biogeography
part of physical geography
is plant succession. This is the explanation in two great
physical geography online
textbooks
http://www.physicalgeography.net/fundamentals/9i.html
https://www.earthonlinemedia.com/ebooks/tpe_3e/biogeography
/plant_succession.html
The basic idea is that a mature vegetation group of plants will
get disturbed by processes
such as forest fires, bulldozers, and even lava flows. Then, after
the disturbance, a series
of changes over time take place. This is a very common type of
diagram for the eastern
United States:
76. However, the way that plant changes after disturbance works
varies a lot in
different places, and climate matters a lot. The Big Island is a
wonderful place to
understand plant succession and how long it takes, because the
ages of the lava flows are
known using radiocarbon dating.
A classic study of plant succession by Mueller0Dombois and
Boehmer studied
lava flows on the east-facing windward side of the Big Island.
This is where the trade
winds are uplifted orographically and the rain is abundant. The
next graphic is are a
series of screenshots from their paper with their basic
conclusions that the transition from
a new lava flow to a tropical rainforest occurs by 400 years.
59
Generally, stages 2-4 in the “Early Development” phase can be
described in the pictures
on the right side. Organisms like lichens, mosses, fungi, ferns
and bryophytes start to
cover the lava flow surfaces, but the flow surfaces are still very
noticeable.
Then, in about 50 years, trees start to come in and the density
of trees continues to
increase until the lava flow is covered with a tropical rainforest
by about 400 years.
77. Thus, there are three general stages:
1) new lava flow
2) lichens and other epilithic (rock surface) organisms cover the
surface and change is
appearance
3) forest takes over
60
The geovisualization shows the basic changes from this study.
The screenshots of the
geovisualization at different places are compared to what is
seen on the ground. Please
take note of how these succession changes look on the
windward (trade wind facing east
side) side of the Big Island, because you will be answering a
matching question on this.
The rainshadow side of the Big Island also has plant
succession, but it is much
slower. It takes over 10,000 years to go from a fresh lava flow
to the end-vegetation type
of desert scrub and small trees some times called kiawe (or the
tree of life in its native
South America). The first step you can see in the
geovisualization is still fresh lava (0-
400 years).
78. The second step is the coating of silica glaze (its too dry for
lichens and plants
like mosses and ferns) that lasts from ~400 years to 3000 years.
From 3000 to 5000, grasses come in but the silica glaze
covered lava is obvious.
Then, grasses and some desert scrub gradually increase from
5000 to 10,000 years.
On lava flows older than 10,000 years, the local scrubland-
dwarf tree plant
association can be dominated by a type of mesquite tree called
Prosopis pallida. This
mesquite is also called kiawe. It originated in Peru and arrived
in Hawai’i in 1828 in a
churchyard in Honolulu. It has since spread and grows on the
rainshadow sides of the Big
island. Its seed pods can be a food source for people and
livestock, brewed into a tea or
sometimes used to make beer
61
These are some ground views of the changes from fresh lava, to
silica glaze, to desert
scrub vegetation over 10,000 years.
These are views from the geovisualization of these same stages
of succession after a new
lava flow.
79. 62
EXAMPLE CANVAS QUESTIONS ON STAGE B TASK 5:
Plant Succession after
a lava flow on the windward and leeward sides of the Big
Island.
The three coordinates are near to one another on the
rainshadow side of the Big
Island. They represent the three stages in plant succession
typically found on the drier
semi-arid/desert slopes on the leeward sides of the volcanoes.
Select the best matches
between location and the stage.
Note: there are pools of questions and your choice will
not be the same as this
example. Also, the example below shows the correct matches.
Canvas will
automatically scramble your choices.
Locations Choices
19.7698 -155.6601 Basalt lava flow less than 200 years
19.7539 -155.6669 Lava flow about 2000-3000 years
old that has been coated with silica
glaze giving it a brownish
coloration, instead of the original
black of the underlying basalt flow.
80. 19.7448 -155.6831 Lava flow that is older than 10,000
years. It has been colonized by a
mixture of grassland and desert
scrub vegetation including
mesquite.
The three coordinates are near to one another on the windward
side of the Big
Island. They represent the three stages in plant succession
typically found on wetter
slopes of the Big Island. Select the best matches between
location and the stage.
Note: there are pools of questions and your choice will
not be the same as this
example. Also, the example below shows the correct matches.
Canvas will
automatically scramble your choices.
Locations Choices
19.1866 -155.7600 Basalt lava flow less than 50 years
19.1905 -155.7659 Lava flow about 150 years old that
is covered with lichens, ferns,
mosses, and scattered trees.
19.1900 155.7991 Lava flow that is about 800 years
old, and it is covered in rainforest.
63
STAGE D: Your analysis of the Physical Geography of the Big
81. Island of Hawai’i
This is your chance to combine observations made doing this
lab with your own
experience (including outside readings and your own travels).
Keep in mind that the
grading of this essay is based on the evidence and reasoning
that you present.
Answers that do not refer to specific evidence from this lab (and
outside material) will be
given little credibility and will not receive full points. In other
words, if we do not see
clear evidence from this lab (and outside material), do not
expect any points.
We do not have any particular answer in mind. We want to
know your opinion, but
backed up by evidence and reasoning (beefy paragraphs).
You do not have to do this essay. It simply provides you an
opportunity to synthesize the
lab and let us know your thinking on the basic questions of the
lab.
Paragraph 1. Using your understanding of the volcanoes of the
Big Island of Hawaii,
please summarize their volcanic features. You can pick just one
of the volcanoes, or you
can generalize for all of them.
Paragraph 2. Using your understanding of how geomorphology
processes (e.g.
development of river valleys, glaciations, rock coatings) have
modified the volcanoes of
the Big Island, please explain how these processes changed the
82. landforms from their
original volcanic morphology and appearance.
Paragraph 3. The lab covered some basic processes in
climatology and meteorology such
as adiabatic processes, condensation of clouds, rainshadow
effects, dew point gradients,
changes in precipitation from place to place, and the trade wind
inversion. Pick two of
these processes and explain their importance with an example
each for the Big Island.
Paragraph 4: The upper elevation treeline on the eastern slopes
(southeast-facing, east-
facing, and north-east facing) of the volcanoes of the Big Island
Hawai’i is a dramatic
change in plant geography. Summarize your understanding of
this upper elevation
treeline in terms of where you would expect to find it, what
climatic differences occur at
and just above the treeline, and what is responsible for this
dramatic change.
The point scoring is divided evenly between the paragraphs. The
assigning of points is
based on the level of detail you provide in writing teach
paragraph.