PHOTOS: ‘Submarine Tumulus’ No Longer an Island

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The U.S. Geological Survey released these photos of the East Rift Zone on Thursday, Aug. 2, 2018.

An aerial view of Kīlauea Volcano’s summit taken on Aug. 1.

Halema‘uma‘u on Aug. 2, 2018. Click to enlarge. PC: USGS

A section of Hawai‘i Volcanoes National Park’s Crater Rim Drive and the road leading to the Kīlauea Overlook parking area are visible at lower right. HVO, Jaggar Museum, and the museum parking area are visible at far middle right. A down-dropped section of the caldera floor can be seen to the left of Halema‘uma‘u, a crater that continues to grow. On the caldera rim (upper right) light-colored ash deposits from explosions in May are stirred up by brisk winds, creating a dust cloud that’s blown downwind.

Then and now. It has proven difficult to exactly match past and present views of Kīlauea’s summit to show the dramatic changes in the volcanic landscape, but here’s our latest attempt.

Then and now. Click to enlarge. PC: USGS

At left is a photo taken on November 28, 2008, with a distinct gas plume rising from the vent that had opened within Halema‘uma‘u about eight months earlier. At right is a photo taken on August 1, 2018, to approximate the 2008 view for comparison.


Kīlauea lower East Rift Zone

During this morning’s overflight, HVO geologists used a telephoto lens to capture this image of the Fissure 8 cone.

Fissure 8 cone on Aug. 2, 2018. Click to enlarge. PC: USGS

Activity within the vent was low, with small bubble bursts in the eastern part of the vent and low lava fountains on the western side. The fountains occasionally threw spatter onto the west rim of the cone (right).

An early morning aerial view (looking west) of the Fissure 8 lava channel.

East Rift Zone on Aug. 2, 2018. Click to enlarge. PC: USGS


Downstream of the vent, the channel splits to form a “braided” section in the lava channel, and, this morning, the north (right) arm of the braided section appeared to be partially abandoned. Lava was still visible in part of the northern braid, but the lower section was only weakly incandescent. During today’s overflight, lava within the channel generally appeared to be at a lower level than in previous days.

During this morning’s overflight, the ocean entry laze plume was being blown offshore, allowing this fairly clear view (looking northeast) of the Pohoiki boat ramp at Isaac Hale Beach Park.

Pohoiki boat ramp at Isaac Hale Beach Park. Click to enlarge. PC: USGS

Incandescent (glowing red) spots of lava can be seen within the flow field beyond the boat ramp. HVO geologists also observed a few oozes of lava on or near the western flow margin, but all appeared weak as of 6 a.m.

On July 13, an image of a tiny “island” forming just offshore of the Kapoho ocean entry could be seen.


On Thursday, Aug. 2, 2018, that feature—likely a submarine tumulus of lava that built up underwater and emerged above sea level—is no longer an “island.”

No longer and island. Click to enlarge. PC: USGS

It now looks more like a peninsula, attached to the coast by a black sand tombolo, a sandy isthmus, creating a feature known as a “tied island.” Whether or not it will withstand wave erosion over time remains to be seen.

Back to Kīlauea’s summit

Rockfalls along Kīlauea’s caldera walls are common during summit collapse events.

Kīlauea Summit. Click to enlarge. PC: USGS

This image, taken just after today’s 11:55 a.m. collapse, shows dust rising from rockfalls along Uēkahuna Bluff.

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