Tilt, Eruptions, and Earthquakes (Grades 9-12)
The relationships between tilt, eruptions, and earthquakes are explored,
using the graphs in activity 10. These data are from the ongoing
eruption of Kilauea Volcano when activity was characterized by high
at the Puu Oo
vent (Wolfe and others, 1987).
here for the graph
for activity 10.
here for the handout
for activity 10.
Students are required to interpret the graph to answer the following
- Is there a correlation between tilt and eruptions?
Yes. Each eruption is marked by rapid subsidence of the summit.
- In terms of tilt, what happens at the summit
The summit of the volcano gradually inflates
- Does the summit inflate to the same tilt angle
prior to each eruption?
No. For example, compare episode 15 and 17.
- Do short-period caldera earthquakes correlate with tilt and/or
Yes. During the eruptive episodes, the
short-period caldera earthquakes is low. As the summit inflates after
each eruption, the number of short-period caldera earthquakes gradually
- Do long-period caldera earthquakes correlate with tilt and/or
Yes. Large numbers of long-period
earthquakes occur during rapid summit deflation and eruptive episodes.
Long-period caldera earthquakes are rare between eruptive episodes.
- Does summit tremor correlate with tilt and/or the eruptive
Yes. Summit tremor increases during rapid summit deflation and eruptive
episodes. Summit tremor is rare between eruptive episodes.
- 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
- 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
- After the eruption, the cycle, with some minor variations, is repeated.