Science Spotlight

Station PUOC

Researcher: Michael Poland
United States Geological Survey

Kilauea Volcano is always changing, almost on a daily basis. The work is never boring.

Site PUOC is anchored to the flank of Puu Oo, an active lava vent on Kilauea Volcano in Hawaii. Click on the photograph to enlarge it to see just how close the instrument is to an open fissure.

Name: PUOC
State: HI
Country: United States
Elevation: 892.0 m
Lat/Long:  19.3903 / -155.1064

Kilauea Eruption

Kilauea Volcano, on the Island of Hawaii, is one of the most active volcanoes in the world. The volcano has been erupting since 1983. PUOC is the key site on Puu Oo (Pooh-ooh Oh-oh)—the vent on Kilauea's east rift zone that has been active since January of 1983.

Monitoring ground motion, or deformation, can tell us whether:
  • magma is accumulating beneath the vent,
  • large lava flows are taking place, or
  • magma is withdrawing into the vent's plumbing system (perhaps to feed eruptive activity elsewhere on the volcano).

The station is right on the north rim of the cone, and responds with sudden shifts (displacements) to changes in volcanic activity. Some of the most spectacular events occurred in 2007 and 2011.

In June of 2007, Puu Oo collapsed as magma withdrew from beneath the cone to feed an intrusion and eruption closer to the summit of Kilauea.

One month later, after much of Puu Oo crater had refilled, a new eruption occurred on the east flank of Puu Oo. This became the main location of eruptive activity for the next 3.5 years.

Both the June and July events were well-recorded by the PUOC GPS station. The June event featured motion towards Puu Oo crater, while the station moved away from Puu Oo's east flank during the July event (as the east part of the cone inflated due to the new eruption).

In March of 2011, the crater collapsed as magma withdrew to feed a fissure eruption a few kilometers away. The crater collapsed again in August as Puu Oo, which had refilled with lava, sprung a leak and drained.

In September, a new eruptive vent formed on the east side of Puu Oo.

The March and August events featured deflationary deformation, with the GPS station moving towards the crater, while the station moved away from the new eruption site during the September event.

Figure 1. This image was acquired by the Advanced Land Imager on NASA's Earth Observing-1 satellite on December 11, 2009. You can see the east rift zone from Kilauea caldera, in the upper left, to Puu Oo, with the largest steam plume. Can you trace the rift zone? What are the ovals? What is the green? What is the gray and black? (Credit: NASA Earth Observatory)

Figure 3. This graph shows the motion of PUOC from June 10, 2006 to August 20, 2009. What direction is the site moving before the June 2007 eruption? (North, south, east, west, or something in between?) What was the displacement during the June 10 eruption? (How much did it move north or south, east or west, and up or down?) What direction did the site move between the June and July eruptions? (For help interpreting the graphs, see the GPS Data page.)

Figure 5. This graph shows the motion of PUOC from 2009 to 2012. What direction did the site move during the events in 2011? PUOC is on the north rim of the Puu Oo cone. Did it move toward the crater, or away from the crater? Up or down?


Figure 2. In the beginning of the eruption, lava fountaining was common at Puu Oo. This photograph was taken on July 28, 1984. (Photo: USGS)

Figure 4. Puu Oo crater on August 7, 2007. Can you find site PUOC? It's a tough one! (Hint: look at the fissures and compare them to what you see in the site photo at the top of this page. You may be able to just make out site PUOC as a white dot. It's up high on the cone, on the right-hand side of the photo!) (Photo: USGS)

Figure 6. Breakout of lava on Thanksgiving Eve, November 21, 2007, from the fissure east of Puu Oo. The open channel system is visible in the background. Since the eruption started in 1983, more than 200 homes have been destroyed by lava. (Photo: USGS)

Spotlight Questions

  • What are some possible reasons site PUOC moved in different directions during the June and July 2007 eruptions? If you were far from the volcano, how could you use this information to infer what was happening at the volcano?
  • The eruption at Kilauea has been ongoing since 1983, but the volcano's behavior has changed several times. If you were a scientist monitoring the data in the second plot, when would you want to go out into the field to see whether the eruption changed? Did it change in the same way each time?

Last modified: 2019-12-26  16:24:50  America/Denver  


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