Geoscience problem set, includes plotting graphs on excel

Geoscience problem set, includes plotting graphs on excel


Geosc 001, Spring 2019
Problem set #1: Hawaii and Indonesia
This problem set is designed to help you focus on the relationships between volcanism and plate motion.
Note that there are three parts to the problem set, and all of the figures are located after the problem set so
you will need to explore the entire document in order to answer the questions. No need to print and hand
in the figures, just the first two pages here (with your answers) and the graphs. Be sure to include your
name on the first page!
You will need to hand in the following items:
Part I – a graph and answers to questions below
Part II – a graph and answers to questions below
Part III – a paragraph-long answer
All parts are due in class on Friday February 8th.
Part I:
What is the relationship between the motion of the Pacific plate and that of the Hawaiian hot spot over the
last 70 million years?
1. Examine the maps of Hawaii that show the entire Emperor Seamount volcanic chain
2. After reading the information provided, plot in Excel the relationship between volcano age (on the
x-axis) and distance from Kilauea (on the y-axis).
3. After plotting the data, determine the relative motion of the hot spot and the Pacific plate. In order
to determine that relationship answer the following questions:
a. What is the slope of the line (be sure to include units)?
b. What does the slope represent?
c. What is the slope in mm/yr?
d. How does this rate compare to the spreading rate of the Mid-Atlantic Ridge (about 1
cm/yr)?
e. When did the orientation of the Hawaiian-Emperor chain change?
f. Is this change manifest on your graph of distance versus age? If so, how?
Hawaii / Indonesia Activity – Tanya Furman
Part II:
What is the relationship between the motion of the Asian plate and that of the Indonesian volcanoes?
1. Observe the geological map that shows the location of the major Indonesian volcanoes.
2. Determine the age of the volcanoes (use units that correspond to those used in Hawaii).
3. Starting from the westernmost Indonesian volcano, plot a graph that shows distance vs. eruptive
age as you did for Hawaii
4. Compare this graph to the one you made for Hawaii. Answer the following questions:
a. How are they alike?
b. How are they different?
Part III:
Summary Question: Describe and contrast the formation of Hawaiian and Indonesian volcanoes. What
are the relationships between volcanic eruptive style, volcanic age, volcanic formation and plate tectonics?
Write a brief but coherent paragraph to answer this question.
Hawaii / Indonesia Activity – Tanya Furman
The Hawaii – Emperor seamount chain
Hawaii / Indonesia Activity – Tanya Furman
Formation of the Hawaiian Islands
(Hawaii Center for Volcanology)
The Hawaiian Islands are volcanic in origin. Each island is made up of at least one primary volcano,
although many islands are composites of more than one. The Big Island, for instance, is constructed of 5
major volcanoes: Kilauea, Mauna Loa, Mauna Kea, Hualalai and Kohala. Mauna Loa is the largest active
volcano on Earth. Kilauea is presently one of the most productive volcanoes on Earth (in terms of how
much lava it erupts each year). The primary volcanoes on each island are known as shield volcanoes,
which are gently sloping mountains produced from a large number of generally very fluid lava flows.
Hawaiian volcanoes primarily erupt a type of rock known as basalt. When molten, basalt produces liquids
of relatively high fluidity, compared to volcanoes that erupt more silica rich magma types such as andesite,
dacite or rhyolite. The fluidity of molten basalt favors the formation of lava flows, which is why the
Hawaiian volcanoes generally have gentle sloping sides. By contrast, lavas with higher silica content are
more viscous and commonly produce either thicker, shorter lava flows, thick blocky deposits and/or thick
beds of ash that fall from the sky following explosive eruptions. These other types of volcanoes (common
outside of Hawaii) are typically steeper sided.
The Hawaiian volcanoes were produced by the Hawaiian hot spot, which is presently under the Big Island
of Hawaii. The image below shows the islands of the Hawaiian chain and the intervening shallows, banks
and reefs along a line from southeast to northwest. Note that the islands of Lanai and Kahoolawe are not
shown because they would “overlap” with Molokai and Maui, respectively. In general, when you move
along the island chain from southeast (Hawaii) to northwest, (Kure), the volcanoes become older and
older.
Hawaii / Indonesia Activity – Tanya Furman
The aging of the islands with distance from the current hot spot is demonstrated in the diagram below,
where distance along the chain is approximated as distance away from Kilauea volcano (the youngest
above-sea-level Hawaiian volcano). In fact, even beyond Kure the Hawaiian chain continues as a series
of now-submerged former islands known collectively as the Emperor seamounts. The two primary
volcanoes that make up Oahu (where Honolulu is) have not erupted for well over a million years!
Note that the axes here are REVERSED from what you will draw in Excel
The age trend of the volcanoes reflects the way in which the islands are built on the moving sea floor of
the North Pacific Ocean: the Pacific Ocean is essentially a single tectonic plate (the Pacific Plate) that is
moving over the Earth’s asthenosphere. As the plate moves over a fixed spot deeper in the Earth where
magma (molten lava) forms, a new volcano can punch through this plate and create an island. The
Hawaiian Islands are believed to be formed from one such’hot spot. As the plate moves away, the volcano
stops erupting and a new one is formed in its place. With time, the volcanoes keep drifting westward and
getting older relative to the one active volcano that is over the hot spot. As they age, the crust upon which
they sit cools and subsides. This, combined with erosion of the islands once active volcanism stops, leads
to a shrinking of the islands with age and their eventual submergence below the ocean surface.
Importantly, the time over which various active volcanoes on the islands remain active is long (hundreds
of thousands of years) so that significant overlap in ages occur on neighboring islands. For instance,
although Haleakala volcano on Maui is a great distance away from the presently erupting Kilauea,
Haleakala last erupted only about 200 years ago.
Hawaii / Indonesia Activity – Tanya Furman
Currently there are 3 Hawai’ian volcanoes that we can easily classify as active:
1. Kilauea, actively erupting since 1983 (and spectacularly this past year)
2. Mauna Loa, which last erupted in 1984 and is building for a new eruption in the next few years
3. Loihi, which erupted in 1996
All three of these active Hawaiian volcanoes share the Hawaiian hot spot, but retain unique volcanic
histories and compositions.
The most likely dormant volcanoes are:
1. Hualalai, which last erupted in 1801
2. Haleakala, which last erupted in about 1790
3. Mauna Kea, which last erupted about 4,000 years ago.
Kilauea and Loihi share the Hawaiian hot spot with their larger active sibling Mauna Loa. With time, the
motion of the Pacific Plate has brought Loihi closer to the center of the hot spot and (possibly) moved
Mauna Loa away from the center. The schematic diagram below shows how one plume might feed these
three different magmatic centers. It is worth noting that although generally similar, there are distinct
compositional attributes of basalts erupted at Mauna Loa, Kilauea and Loihi, indicating that the way in
which each volcano “samples” the hot spot is slightly different.
TODAY:
Mauna Loa
—-/ x
/
x

Kilauea
/
x
/
—–/—————-x———– sea level
/
x
x
_
/
x
x
/
/
x
x
x Loihi
x
x
x

x
x
x

x
x
x

x
x
x

x x x
x
xxxxxxxxx
xxxxxxxxxxx
xxxxxxxxxxx
Hawaii / Indonesia Activity – Tanya Furman
Table 1: Ages of some of the Hawaiian Islands and outer seamounts
Volcano Number
Volcano Name
1
3
5
6
7
8
9
10
11
12
13
14
15
15A
17
20
Kilauea
Mauna Kea
Kohala
Haleakala
Kahoolawe
West Maui
Lanai
East Molokai
West Molokai
Koolau
Waianae
Kauai
Niihau
Kaula
Nihoa
Unnamed
23
26
27
Necker
La Perouse Pinnacles
Brooks Bank
30
Gardner Pinnacles
36
37
50
52
57
63
65
65A
67
69
72
74
81
Laysan
Northampton Bank
Pearl and Hermes Reef
Midway
Unnamed
Unnamed
Colohan
Abbott
Daikakuji
Yuryaku
Kimmei
Koko (southern)
Ojin
Hawaii / Indonesia Activity – Tanya Furman
Distance from
Kilauea (km)
0
54
100
182
185
221
226
256
280
339
374
519
565
600
780
913
930
1,058
1,209
1,256
1,330
1,435
1,460
1,818
1,841
2,281
2,432
2,600
2,825
3,128
3,280
3,493
3,520
3,668
3,758
4,102
Best K-Ar age (Ma)
0-0.4
0.375 + 0.05
0.43 + 0.02
0.75 + 0.04
> 1.03 + 0.18
1.32 + 0.04
1.28 + 0.04
1.76 + 0.04
1.90 + 0.06
2.6 + 0.1
3.7 + 0.1
5.1 + 0.20
4.89 + 0.11
4.0 + 0.2
7.2 + 0.3
9.2 + 0.8
9.6 + 0.8
10.3 + 0.4
12.0 + 0.4
13.0 + 0.6
13.0 + 0.6
12.3 + 1.0
12.3 + 1.0
19.9 + 0.3
26.6 + 2.7
20.6 + 2.7
27.7 + 0.6
28.0 + 0.4
27.4 + 0.5
38.6 + 0.3
38.7 + 0.9
42.4 + 2.3
43.4 + 1.6
39.9 + 1.2
48.1 + 0.8
55.2 + 0.7
83
86
90
91
Jingu
Nintoku
Suiko (southern)
Suiko (central)
4,175
4,452
4,794
4,860
55.4 + 0.9
56.2 + 0.6
59.6 + 0.6
64.7 + 1.1
“Volcano Number” refers to the number in sequence along the Hawaiian Chain. Loihi, the youngest
expression of the Hawaiian hot spot is number 0, Kilauea is number 1, etc.. Note that not all volcanoes
are listed in the table (e.g., number 2 = Mauna Loa and number 4 = Hualalai); also note that further up
the chain, the numbering scheme becomes more subjective.
Volcanoes of Indonesia (From: Simkin and Siebert, 1994, Volcanoes of the World: Smithsonian
Institution and Geoscience Press, Inc., Tucson, Arizona, 349pp.)
Hawaii / Indonesia Activity – Tanya Furman
Indonesia consists of more than 13,000 islands, spread over an area approximating that of the
conterminous United States. Although Chinese records show a Krakatau eruption in the 3rd century AD,
and some 17 additional historical eruptions are reported from Kelut as well as Krakatau through the 15th
century, uncertainty surrounds many of them. Europeans first began to document eruptions in 1512
(Sangeang Api and Gunungapi Wetar), about the time Portugal gained control of the Mollucan clove trade.
The disastrous Krakatau eruption of 1883 was followed by several devastating eruptions on other islands
and in 1920 a Volcano Survey was established by the government, leading to much improved volcano
monitoring and reporting. The Volcanological Survey of Indonesia (VSI) now operates a network of 64
volcano observatories continuously monitoring 59 volcanoes.
The great sweep of the Sunda Arc, over 3,000 kilometers from NW Sumatra to the Banda Sea, results
from the subduction of the Indian Ocean crust beneath the Asian Plate. This arc includes 76% of the
region’s volcanoes, but those on either end are tectonically more complex. To the NNW, the basaltic
volcanism of the Andaman Islands results from short spreading centers, and to the east the Banda Arc
reflects Pacific Ocean crust subducted westward. North of this arc, tectonic complexity increases, with
converging plate fragments forming multiple subduction zones, mainly oriented N-S, that in turn produce
the Sulawesi-Sangihe volcanoes on the west and Haimahera on the east of the collision zone.
Indonesia leads the world in many volcano statistics. It has the largest number of historically active
volcanoes (76), its total of 1,171 dated eruptions is only narrowly exceeded by Japan’s 1,274, and these
two regions have combined to produce 1/3 of the known explosive eruptions. Indonesia has suffered the
highest numbers of eruptions producing fatalities, damage to arable land, mudflows, tsunamis, domes, and
pyroclastic flows. Four-fifths of Indonesian volcanoes with dated eruptions have erupted in this century
Hawaii / Indonesia Activity – Tanya Furman

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