USGS Preliminary Analysis_LERZ_7-15-18_v1.1

Home

Fissure 8 was first active May 5, but reactivated during the third week of May with episodic spattering, and began to erupt with a vigorous fountain late in the day on May 27, producing a relatively fast moving channelized flow that travelled northeast. The fountain abruptly stopped the following morning (May 28), and the flow it fed stalled after crossing Pohoiki Road. Fissure 8 restarted later the same day, however, and began feeding a new fast-moving, channelized flow northeast and depositing tephra downwind. This new flow crossed Pohoiki Road early the next morning (May 29) and Highway 132 in the afternoon, isolating Puna Geothermal Ventures (PGV). The fissure 8 channelized flow continued to advance rapidly downslope over the following days, reaching the ocean at Kapoho Bay late in the day on June 3. The flow filled the bay and spread along the coast quickly, destroying hundreds of homes and the tide pools south of Kapoho Bay. Fountaining and spattering from fissure 8 began constructing a spatter cone (fig. 2), which by the end of June was about 55 m (180 ft) high and open to the northeast. Discharge from the vent continues to feed directly into the relatively stable channel, which carries lava 13 km to the ocean. Although difficult to measure, the most plausible estimates of the eruption rate from fissure 8 range from 50 to 150 m3/s. After several blockages and subsequent clearing or channel rerouting around the blockage to keep the channel flowing to the north and east of Kapoho Crater, the channel overflowed just northwest of Kapoho Crater and a new lobe advanced southward along the west margin of the previous flow and entered the ocean on July 12. This diversion of the channel flow was the first major change in the fissure 8 channel. Even though the channel no longer directly fed the massive lava delta to the southeast of Kapoho Crater, lava continues to ooze out of the flow front into the ocean in many locations. Ongoing fissure 8 hazards Figure 2. Fissure 8 fountains within a cinder and spatter cone feeding a wide channelized flow. U.S. Geologicol Survey( USGS) Photo token on June 22, 2018.