Monitoring the Mauna Ulu Eruption (Grades 9-12)
From 1969 to 1974, Kilauea Volcano erupted on the upper east rift
zone, constructing the
Mauna Ulu
vent. The eruption was
monitored by several
methods, and some of the data are presented graphically in this activity.
Click
here for the graph
for activity 11.
Click
here for the handout
for activity 11.
Students are required to interpret the graph to answer the following
questions.
- Is there a correlation between tilt and eruptions?
Yes. Each eruption is marked by rapid subsidence of the summit.
- Based on tilt, what happens at the summit before eruptions?
The summit of the volcano gradually inflates between eruptions.
- Does the summit inflate to the same tilt angle prior to each
eruption?
No. For example, contrast episode 15 and 17.
- Does the number of shallow summit earthquakes correlate with
tilt
and/or the eruptive episodes?
Yes. During the eruptive
episodes,
the number of shallow summit earthquakes is low. As the summit inflates
after each eruption, the number of short-period caldera earthquakes
gradually increases.
- Based on the data presented in the graphs, outline the geologic
events leading up to, during, and after an eruptive episode.
- Magma accumulates in the summit reservoir, causing the volcano to
inflate and tilt to increase.
- As more magma accumulates and the volcano continues to inflate, the
rocks above and around the magma reservoir deform and create short-period
caldera earthquakes.
- At the onset of the eruptive episode, magma leaves the summit
reservoir, causing the summit to rapidly deflate. Summit tremor
indicates that the magma is moving. Long-period caldera earthquakes
indicate that magma is rising from deep beneath the volcano to resupply
the summit reservoir.
- After the eruption, the cycle, with some minor variations, is repeated.
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