Posted on February 2, 2017.
UPDATE: Sea Cliff collapses into the ocean at Kamokuna Ocean Entry
The section of sea cliff above the ocean entry collapsed Thursday (Feb 2) at about 12:55 p.m. The sea cliff had become increasingly unstable as a large crack 5–10 m (16–33 ft) inland of the ocean entry had more than doubled in width, from 30 cm (1 ft) to 70 cm (2.5 ft), over the past several days. A video camera, which had just been set up to monitor movement of the crack near the sea cliff, captured the moment of collapse. Video taken Thursday, February 2, 2017 courtesy of USGS/HVO
HVO geologists hiked to the Kamokuna ocean entry today to assess the status of the sea cliff. When they arrived, the “firehose” flow was no longer visible. However, spatter (bits of molten lava) and black sand flying through the steam plume indicated that lava was still flowing into the ocean and interacting explosively with seawater. Just below the left side of the steam cloud, a small shelf of the Kamokuna lava delta that survived the New Year’s Eve collapse can be seen. Photo taken Thursday, February 2, 2017 courtesy of USGS/HVO
Within minutes of HVO geologists reaching the ocean entry site, the sea cliff seaward of the hot crack (see Jan. 30 images) collapsed with no warning; fortunately, they were far enough away to not be in harm’s way. The top photo was snapped just before the collapse occurred. The bottom image shows the remaining sea cliff after the collapse. Yellow arrows point to the same rocks in both photos for comparison. Photos courtesy of USGS/HVO
The entire section of the sea cliff that was seaward of the hot crack collapsed, except for a small block of rock (left) at the eastern end of the crack; this piece of the sea cliff, estimated to be 30 m long and 5 m wide (98 x 16 ft), remains highly unstable and could collapse with no warning. During the collapse, rocks hitting the ocean generated a wave that propagated outward from the coast. After the collapse, no lava was visible, but is apparently still flowing into the sea based on the continuing steam plume and explosions of spatter. Photo taken Thursday, February 2, 2017 courtesy of USGS/HVO
The open lava stream at the ocean entry, and the frequent littoral explosions. Video courtesy USGS/HVO.
Time-lapse thermal image movie of Halemaumau Overlook Vent. January 26-February 2, 2017. Images courtesy of USGS/HVO
Time-lapse movie of Halemaumau Overlook Vent. January 26-February 2, 2017. Images courtesy of USGS/HVO
Time-lapse movie of Halemaʻumaʻu Overlook Vent from Hawaiian Volcano Observatory. January 26-February 2, 2017. Images courtesy of USGS/HVO
Time-lapse movie of Kīlauea Caldera from Hawaiian Volcano Observatory. January 26-February 2, 2017. Images courtesy of USGS/HVO
Time-lapse movie of Halemaumau Crater looking Southwest. January 26-February 2, 2017. Images courtesy of Hawaii Volcanoes National Park
(Activity updates are written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)
Kīlauea continues to erupt at its summit and East Rift Zone. This past week, the summit lava lake level varied between about 13 and 23 m (43–75 ft) below the vent rim. The 61g flow was still active, with lava entering the ocean near Kamokuna and surface breakouts near Pu‘u ‘Ō‘ō. The sea cliff adjacent to the Kamokuna ocean entry has become highly unstable and could collapse with no warning. The 61g flows do not pose an immediate threat to nearby communities.
Mauna Loa is not erupting. During the past week, small-magnitude (up to magnitude-3.0) earthquakes continued, primarily beneath the upper Southwest Rift Zone and the Northeast Rift zone at depths less than 5 km (3 mi). A small number of earthquakes also occurred on the west flank of the volcano at depths above 13 km (8 mi). Measurements at a fumarole site within the summit caldera showed an increase in temperature during the first half of January, but relatively steady fumarole temperatures were measured over the past week. There was no significant change in sulfur dioxide or carbon dioxide concentrations in the volcanic gas emissions.
Two earthquakes were reported felt in Hawaii this past week. On January 31, 2017, at 10:45 p.m., HST, a magnitude-3.7 earthquake occurred 62.3 km (38.7 mi) southwest of Makena, Maui, at a depth of 36 km (22 mi). On January 26, at 10:16:32 p.m., HST, a magnitude-3.1 earthquake occurred 5.6 km (3.5 mi) southwest of Mauna Loa’s summit, Hawaiʻi, at a depth of 3 km (2 mi).
Please visit the HVO website (hvo.wr.usgs.gov) for past Volcano Watch articles, Kīlauea daily eruption updates, Mauna Loa weekly updates, volcano photos, recent earthquakes info, and more; call for summary updates at 808-967-8862 (Kīlauea) or 808-967-8866 (Mauna Loa); email questions to askHVO@usgs.gov.
An open lava stream continues to pour out of the lava tube, perched high on the sea cliff, and into the ocean. The stream was remarkably steady today, but produced pulsating littoral explosions that threw spatter onto the sea cliff. Photo taken Saturday, January 28, 2017 courtesy of USGS/HVO
A wider view of the ocean entry. Photo taken Saturday, January 28, 2017 courtesy of USGS/HVO
Near the base of the lava stream, just above where it impacted the water, there were commonly ripples in the stream, suggesting this was a narrow sheet of lava. These ripples can be seen on the lower right side of the lava stream. A few small, steaming clasts thrown up by a small littoral explosion are visible in front of the stream. Photo taken Saturday, January 28, 2017 courtesy of USGS/HVO
A close up of the stream near the spot where it exits the tube. This view was only possible with a very high magnification lens. Photo taken Saturday, January 28, 2017 courtesy of USGS/HVO
The lava stream, pouring out of the lava tube on the sea cliff at the Kamokuna ocean entry, continues and was similar to yesterday. The stream appeared wider (as viewed from this angle) today compared to yesterday, and often had holes in the thin sheet. The entry was still producing small, pulsating littoral explosions. Photo taken Sunday, January 29, 2017 courtesy of USGS/HVO
A wider view of the ocean entry, at sunset. Photo taken Sunday, January 29, 2017 courtesy of USGS/HVO
Due to the instability of the sea cliff above the ocean entry and other hazards created by molten lava flowing into the sea, Hawaiʻi Volcanoes National Park has established a viewing area (noted by yellow arrow in photo) from which the ocean entry can be seen in relative safety. Photo taken Monday, January 30, 2017 courtesy of USGS/HVO
A thermal image taken during HVO’s overflight of Kīlauea Volcano’s ocean entry on Jan. 25, 2017, revealed a hot ground crack in the sea cliff just above where lava is flowing into the sea. Because the crack suggested an unstable sea cliff, HVO geologists briefly visited the site on foot for closer observations and measurements this past weekend. Photo taken Monday, January 30, 2017 courtesy of USGS/HVO
Carefully approaching the site in protective gear on Jan. 28, HVO geologists determined that the eastern end of the hot crack was about 30 cm (11.8 in) wide and deeply cut into recent lava atop the older sea cliff. The western end could not be accessed due to poor air quality, spatter fallout, and other safety concerns. This crack could be a precursor to collapse of an unstable section of the sea cliff, making the site extremely dangerous for anyone who ventures too closely to the ocean entry by land or by sea. Photo taken Monday, January 30, 2017 courtesy of USGS/HVO
Using a thermal image of the crack above Kīlauea volcano’s ocean entry (steam from lava flowing into the sea is visible at the top of the left photo), HVO geologists determined that the temperature within the eastern end of the crack is up to about 220 degrees Celsius (428 degrees Fahrenheit). Photos taken Monday, January 30, 2017 courtesy of USGS/HVO
At Kīlauea’s ocean entry on Jan. 28 and 29, the interaction of molten lava flowing into cool seawater caused pulsating littoral explosions that threw spatter (fragments of molten lava) high into the air. Some of these incandescent clasts fell on top of the sea cliff behind the ocean entry, forming a small spatter cone. During one exceptionally large burst, spatter was thrown about twice the height of the sea cliff. These ocean entry littoral explosions, both large and small, create hazardous conditions on land and at sea. Photo taken Monday, January 30, 2017 courtesy of USGS/HVO
The hot crack near the sea cliff, in the immediate area of the ocean entry, has widened significantly over the past four days. On Saturday, January 28, the crack was 30 cm wide (1 foot). Today, HVO geologists in protective gear briefly entered the area and measured the crack as being 75 cm (2.5 feet). In this image comparison, the yellow stars show corresponding points in the two images. The arrow also shows how much the crack has widened. Remarkably, grinding noises could be heard coming from the crack, and the block of sea cliff on the makai (ocean) side of the crack could be seen to move slightly. These signs indicate that the section of sea cliff around the ocean entry is highly unstable and could collapse at any time. Photo taken Wednesday, February 1, 2017 courtesy of USGS/HVO
From the lava viewing area established by Hawaiʻi Volcanoes National Park, you can witness Kīlauea Volcano’s ocean entry from a safe distance. With binoculars or a telephoto camera lens, spectacular views and photos are possible (as seen here)—without risking your life by entering the closed area. As lava streams into the ocean, explosive interactions between the molten lava and cool seawater hurl spatter and rock fragments skyward, often as high as the sea cliff, which is about 28 m (92 ft) high. Photo taken Wednesday, February 1, 2017 courtesy of USGS/HVO
This image comparison shows the changing nature of the lava stream between Saturday, January 28 and Wednesday, February 1. The lava stream has become much more narrow, as viewed from this angle. Photo taken Wednesday, February 1, 2017 courtesy of USGS/HVO
Using a telephoto lens, spatter and glassy rock fragments (black sand) from the explosive interaction of molten lava and seawater can be seen flying skyward and seaward. At times, these fragments were thrown high enough to land on the sea cliff above the ocean entry—one of many hazards impacting this area. Photo taken Wednesday, February 1, 2017 courtesy of USGS/HVO
Detailed views of the “firehose” flow streaming from the lava tube, spatter, and rock fragments were provided by zooming the telephoto lens in even closer. Photo taken Wednesday, February 1, 2017 courtesy of USGS/HVO
Time-lapse image movie from a research camera positioned on Holei Pali, looking east towards Lava Flow 61G and Kalapana. January 26-February 2, 2017. Images courtesy of USGS/HVO
Time-lapse multi-image movie of Mokuʻāweoweo Caldera from the Northwest Rim on Mauna Loa. January 26-February 2, 2017. Images courtesy of USGS/HVO