Note: Check the Photo Glossary or a good dictionary for any terms unfamiliar to you.
Map of selected deformation stations
This graph shows the radial tilt at Uwekahuna (UWE), on the northwest rim of Kīlauea's caldera, and at Pu`u `Ō `ō cone (POC), on the northwest flank of the active vent along the east rift zone, as recorded by continuously operating electronic tiltmeters. Positive changes indicate inflation of the magma storage areas beneath the caldera or Pu`u `O`o. The Y-axis is in microradians, an angular measure in parts per million; for example, one microradian represents the tilt of a 1-km-long bar, one end of which is lifted up or down 1 mm.
Data are shown for a one-week period. The electronic tilt display shows relative values rather than absolute values. In other words, we do not assign a specific value to any given time; rather, we look at the difference in tilt over a period of time (hours, days, weeks). The plot is updated and rescaled approximately twice per hour to ensure that changes in tilt are readily apparent over the time period displayed.
Global Positioning System (GPS)
This graph shows the change in distance between two Global Positioning System (GPS) stations located on opposite sides of Kīlauea's caldera. A rapid increase in distance can be interpreted as inflation of the summit magma reservoir. The graph is refreshed once per day.
For more information on how electronic tiltmeters and GPS receivers help monitor the deformation of Kīlauea and Mauna Loa volcanoes, see a summary of the inflation-deflation of magma chambers.
Eruption-viewing opportunities change constantly, so refer to this page often. Those readers planning a visit to Kīlauea or Mauna Loa volcanoes can get much useful information from Hawai`i Volcanoes National Park.