Volcano Watch — Volcano erupts in big show

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Lava activity at the coast where the flows enter the ocean has been spectacular this past week. The activity has included high lava spattering and formation of three new cones along the ocean entries. On Friday, March 4, explosions began at the coast and intensified during the day. By evening, sprays of incandescent lava were jetting 65 to 100 feet high. Large bubbles of lava formed over a hole in the top of the lava tube about 15-20 feet from the ocean. Explosions that lasted from 3 to 7 minutes and occurred every 15 to 25 minutes were accompanied by loud booming noises. Later in the evening, lava jets up to about 300 feet tall sprayed the area with small lava fragments, thin sheets of glass, and Pele's hair.

Other explosions occurred at the end of a submerged tube about 10-15 feet offshore. By Saturday morning, the explosive activity had stopped, and only a small amount of lava entered the ocean, resulting in a greatly diminished steam plume compared with that of previous days and weeks. On Saturday, the lava delta was blanketed with small lava fragments, Pele's hair, and limu o Pele as far as the end of the Chain of Craters Road. Limu o Pele is paper-thin sheets of glass that form as lava bubbles explode, named for its' resemblance to seaweed.

The large surface flow that had begun below Paliuli on Thursday, March 3, continued to slowly advance along the east side of the Kamoamoa flow field on Saturday but had stopped by Sunday. On Sunday, another surface flow began at an elevation of about 2,000 feet and advanced towards the ocean to about the 1,700-foot level before it stopped on Monday. On Friday, March 4, lava could be seen flowing in the tube at a skylight (hole) in the top of the tube at the 2,360-foot elevation.

The lava pond inside Pu'u 'O'o dropped from about 280 feet to about 310 feet below the lowest point on the rim, and activity in the pond was sluggish on Friday, March 4. By Wednesday, the pond surface was active, but lava was upwelling in the middle and flowing both east and west, instead of the west-to-east circulation we have observed for more than a year. The change in circulation probably is caused by the drop in the pond's surface. There has been bright glow over the cone several nights this past week.

More low-level explosive activity began at the coast on Monday, March 7, although the volume of lava was still small, as seen by the small steam plume. Many of the explosions occurred at the end of a submerged tube extending 15-50 feet offshore. At about 2:00 p.m. Tuesday, explosive activity again increased in magnitude, and a new spatter cone formed by the following morning. This cone was about 30 feet tall and was located east of the cone formed on March 3 and 4. Again, the explosions were accompanied by loud, booming noises. By Wednesday morning, the activity was spectacular, with lava spattering and bubbles forming at three separate places along the ocean entries. The lava ledge continued to grow as surface flows built new land along the coastline adjacent to the new cones. This new activity had died out by about 9:00 a.m. on Thursday when lava was entering the ocean at three main places.

The lava ledge along the ocean has now grown to about 1,150 feet wide and is surmounted by three spatter cones, each about 30 feet high. The figure shows the coastal entry area as you would see it from the air. The three cones formed this past week are shown, as is one older cone. The ledge has grown eastward almost to the edge of the figure, but we have not yet mapped it in enough detail to show here. Enormous amounts of limu o Pele and Pele's hair has formed during these explosive episodes, and much of it has been deposited on the lava delta because of the strong onshore Kona winds this past week. The steam plume, which also contains abundant, tiny fragments of this glass, is really a strong solution of hydrocloric acid.

We urge visitors to Hawaii Volcanoes National Park who want to watch this activity at the coast to obey the warning signs posted by the National Park Service and to keep a safe distance away. If you get too close and glass fragments fall on your skin, do not try to brush them off, as you will simply push the sharp glass into your skin. Wash these fragments off with water. The entire area is extremely dangerous, and explosions and spattering of widely variable intensity occur without warning, as do collapses of the youngest lava ledge. Because the present ledge is so large, we anticipate that another major collapse could occur, with large parts of the ledge and its three spatter cones sliding into the sea.