HVO downgrades Kilauea alert level from warning to watch

Puu Oo eruption

Hawaiian Volcano Observatory is downgrading the volcano alert level for Kilauea from “warning” to “watch.”

Eruption of lava continues at both the Puʻu ʻŌʻō vent on Kīlauea Volcano’s East Rift Zone and in Halemaʻumaʻu Crater at the volcano’s summit. However, in recent weeks, the Puʻu ʻŌʻō lava flows nearest to the town of Pāhoa became inactive. Because the immediate threat from the June 27th lava flow has been reduced, the alert level was reduced.

Presently, the only active surface lava occurs in four separate breakouts from the main lava tube within three areas in the upper 6 km (4 mi) of the flow field below the Puʻu ʻŌʻō vent. Lava from these breakouts is moving slowly atop earlier flows and along the margin of the June 27th and the Kahaualeʻa (2013-2014) flow fields. Based on the rate and trajectory of these active flows, we anticipate that it will be at least months before lava could reach to within 1 mile or 1 week of homes or infrastructure.

The ultimate trajectory and path of the lava flow depends on how lava activity evolves in these areas.

Should breakouts along the northern margin of the June 27th flow field become dominant, the resulting lava flow will likely follow steepest lines of descent that approach the Hawaiian Acres and Ainaloa subdivisions.

Should the breakout heading towards the south margin of the June 27th flow field become dominant, the resulting flow will likely parallel the East Rift Zone and approach the Pāhoa area.

At this time, reoccupation of the lava tube that fed lava flows toward the Pāhoa Marketplace area is unlikely. Should this occur, however, delivery of lava farther downslope to the currently inactive extent of the June 27th lava flow field could happen more quickly, perhaps within weeks.

This assessment is based on continued lava production at Puʻu ʻŌʻō at current eruption rates and vent location. Should the eruption rate increase significantly or the locus of eruption shift to a new vent, the conditions of lava flow advance and associated threat could change quickly.

HVO will continue to monitor the volcano closely in cooperation with Hawaii County Civil Defense.

Hazard Analysis:

  • Lava flow: Active lava flows from Puʻu ʻŌʻō are slowly advancing atop earlier flows and along the margins of the June 27th and Kahaualeʻa (2013-2014) flow fields. At current rates of eruption and flow advance, it may be months before lava could approach homes and infrastructure. This time frame could change quickly if eruption rate or location of lava emission changes significantly.
  • Volcanic gas: Significant amounts of sulfur dioxide and other volcanic gasses continue to be released into the atmosphere from both Puʻu ʻŌʻō and Halemaʻumaʻu.
  • Ash fall: Small amounts of ash consisting of volcanic glass (Pele’s hair) and pulverized rock may drift downwind from Halemaʻumaʻu.
  • Other hazards: Methane explosions are possible along the margins of active lava that flows into vegetated areas. These explosions can hurl large blocks of lava rock and heave the ground suddenly and without warning.

Remarks: The Puʻu ʻŌʻō vent in the East Rift Zone of Kīlauea Volcano began erupting on January 3, 1983, and has continued for more than 32 years, with the majority of lava flows advancing to the south. Over the past two years, lava flows have issued from the vent toward the northeast. The June 27th flow is the most recent of these flows and the first to threaten a residential area since 2010-2011.

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