GEOLOGY Homework: Hawaiian volcanism
A two part assignment
1. Rate of plate movement over the Hawaiian hot spot
This hand-out contains a physiographic map of the Hawaiian-Emperor seamount chain (Fig 1).
The active volcanoes on the island of Hawaii and the active submarine volcano Loihi indicate the
current location of the Hawaiian hot spot. Using this map and the following information on the age of
specific islands and seamounts, determine the rate of Pacific plate motion for each of the intervals
between the eruptions that created these seamounts (by using the formula rate = distance/time). Show
your work, and don’t forget to include units in your answer. Remember that for your rate calculation
to be correct, you want the value you use for “distance” to be measured along the actual path the plate
has traveled.
Seamount
or Island
Suiko Seamount
Daikakuji Seamount
Midway Island
Necker Island
Kauai Island
Hawaii
Age (in
millions of yrs)
Difference
in Age
Distance
(in km)
Rate
65
42
28
10
5
0
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2. Eruption precursors at Kilauea
This problem involves interpretation of data related to the 1974 eruption sequence at Kilauea
Volcano. Attached is a general location map of the island of Hawaii (Fig. 2) and another of the main
caldera of Kilauea and the crater within it -- Halemaumau (Fig. 3). On the map of Kilauea (Fig. 3),
outline the main caldera of Kilauea with colored pencil.
The close-up map also shows ground displacement data prior to one of the eruptions. The
elevation was accurately measured along several traverses (at the dots, or stations, shown on the map).
Traverses were made on April 4, 1974 and July 31, 1974. The numbers on the map show the
CHANGE in elevation between these two dates; the ground displacement is given in millimeters, with
movement up shown as positive and down as negative. Contour these data in 10 mm intervals. (It
is okay to draw contours though fault scarps.)
In your report, use your contour map to answer the following questions.
Where was the maximum ground deformation?
Does this deformation represent uplift or deflation?
Over what (minimum) lateral distance did this deformation occur?
In your report, make the following predictions about the imminent eruption:
Where is the most likely site for an eruption to begin?
What pattern of deformation would you expect once an eruption has occurred? Why?
The two parts of this assignment are distinct entities with individual (short) write-ups.
Please turn in the following for EACH of the two parts of this assignment:
1) A ½ page, typed report, using the same outline as your lab reports.
Each ½ page report can be fit on the same sheet of paper (saves paper, smaller
stack for the grader.
2) The data on which this part of the report is based, i.e.,
the Hawaiian-Emperor chain map and table, for part 1
the contour map, for part 2
Please do not turn in any other parts of the hand-out; include only the data necessary to support your
conclusions.
Grading Key:
Hawaiian hot spot, 25 points
Introduction (4 pts) - location of area, problem to be solved
Methods (4 pts) - kinds of data, methods used
Observations (10 pts) - table filled out, work shown
Interpretation (7 pts) - summary of results; assumptions and possible sources of
discussed
inaccuracy
Kilauea, 25 points
Introduction (4 pts) - location of area, problem to be solved
Methods (4 pts) - kinds of data, methods used
Observations (10 pts) - contour map, answers to questions
Interpretation (7 pts) - answers to questions, based on data presented
Terms to Know
Caldera: a crater of depression, typically formed as a result of a magma chamber emptying
Deflation: lowering of the ground surface
Deformation: any change in shape or location of a rock or rock mass
Uplift: (with respect to this homework) rising of the ground surface