Surface lava flows from Kilauea Volcano have been picking up speed across the abandoned Royal Gardens subdivision on Hawaii island, progressing to within about a half-mile of the coast, according to the U.S. Geological Survey’s Hawaiian Volcano Observatory.

The observatory has been tracking the flow via webcam.

The surface activity at the middle east rift zone vents comes during a period of relatively unremarkable activity at Kilauea’s summit.

Tiltmeters at the summit are used to record "deflation-inflation tilt events," in which abrupt deflation lasting a few hours to as many as three days is followed by rapid inflation of roughly equal magnitude. These tilt events are usually accompanied by an increase in summit tremors during the deflation phase.

On Monday the observatory noted a continued weak summit deflation followed by a stronger deflation after midnight.

The observatory also recorded decreased seismic activity in the summit and upper east rift zone of the volcano. Eleven earthquakes were strong enough to be located beneath Kilauea: two within the upper southwest rift zone, one west of the summit caldera, four within the upper east rift zone and four on the south flank faults.

After a month of extension, the observatory’s GPS network recorded neither extension nor contraction across the summit caldera over the last few days, the observatory reported.

The observatory noted elevated activity within the crater at Puu Oo. A small amount of lava issued from the easternmost of the two sources at the south edge of the crater on Monday, and the perched lava lake within the northeast pit remained actively circulating.

Jan. 3 will mark the 30th anniversary of Kilauea Volcano’s current eruption.