English: This graph shows a one-year record of tilt from the Uwekahuna tiltmeter located on rim of Kilauea's caldera. When the tiltmeter record showed an increase in slope angle (microradians) the ground was tilting away from the caldera, which indicates the summit area was inflating with magma. Then, when lava within Pu`u `O`o filled and overflowed the crater or began fountaining, the summit tiltmeter record suddenly showed a decrease in slope angle or deflation. After the eruption, the tiltmeter once again recorded a steady outward tilt.