Volcano Watch — Kīlauea eruption status—lava flows moving toward sea

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Kīlauea's 12-year-old East Rift Zone eruption continues with lava issuing from vents on the southwest flank of Pu'u 'O'o. Since December, the eastern and western boundaries of the Kamoamoa-Lae'apuki flowfield have expanded, and much of the area in between has been resurfaced with new lava. During most of this time, there were four concurrent ocean entries across a three kilometer stretch of coastline. A new 'a'a flow to the west of the main flow field broke out at the 2,100 foot elevation on February 10 and reached Paliuli in four days. The upper reaches of the flow roofed over, and the new tube fed a rapidly spreading pahoehoe sheet on the coastal plain that burned grasslands and set off methane explosions as it advanced. This flow was within 150 meters of Chain of Craters Road before the front stagnated on February 27. As of a week ago, activity on this flow had ceased, but not before archeological sites in the Mo'olehua area (near Paliuli) were partially buried by lava.

The western portion of the main flowfield continues to consume the end of Chain of Craters Road and is advancing westward a few hundred meters mauka of the road. This flow has joined the westernmost flow to form the "Mo'olehua Kipuka." Lava is entering the ocean at a point very close to the High Castle overlook, providing spectacular lava viewing at the end of the road.

The extensive surface-flow activity described above has been ongoing since October. This is in contrast to most of 1994, when lava was efficiently transported from the vents directly to the ocean in a well-developed (mature) lava tube system. The change in behavior is a result of the three brief pauses in the eruption that occurred in October and November. After each pause, the lava tube system was reoccupied only from the ventto the top of Pulama Pali. The top of the pali is always a weak spot in the tube system because of the abrupt change in slope. Following each pause, the lava broke out at this point, and new surface flows advanced down the pali. Since the last pause at the end of November, a mature tube system has not had time to develop within the new surface flows.

Below the 1,900 foot elevation, two new lava tubes are currently feeding lava to ocean entries on the eastern and western sides of the Kamoamoa lava delta. The volume of lava actually entering the ocean is still relatively small, because surface flows are widespread on the coastal plain. If the eruption continues without a pause, mature tube systems may develop on either the Laeapuki or the Kamoamoa side of the flowfield, or both.

During the last few days, we observed signs of a "slow down" in eruptive activity. The amount of lava issuing from the vents decreased significantly between Tuesday and Friday. At the same time, the summit of Kīlauea inflated, and the number of shallow summit earthquakes increased. Taken together, these observations indicate that the magma reservoir beneath the summit was filling and that less lava was reaching the East Rift Zone eruption site. On Friday, the ocean entries were dead, but large `a`a flows were advancing down Pulama Pali, suggesting that the eruption volume was back to normal. As always, it's a good idea to call the National Park Service for an eruption update before you embark on a lava-viewing excursion.