The Great Crack: Photos and information wanted.

[SBH]

That’s some Great Crack.

[bananahead]

Ive hiked it a few times, its OK.. same with Devils Throat..... not as impressive as it sounds but cool to 'check off the list'

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save our indigenous and endemic Hawaiian Plants... learn about them, grow them, and plant them on your property, ....instead of all that invasive non-native garbage I see in most yards... aloha

[bananahead]

imo... this is the coolest thing in Kau ...

https://www.researchgate.net/publication...ehu_Hawaii

https://www.researchgate.net/publication...yph_fields


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save our indigenous and endemic Hawaiian Plants... learn about them, grow them, and plant them on your property, ....instead of all that invasive non-native garbage I see in most yards... aloha

[pbmaise]

Thanks Glinda for the reference material to read.

Roger Denlinger does indeed map the crack of interest and calls it a listic fault and part of the "Hilina Fault System".

The whole point of my blog is to examine the question if lava incursion is happening into this fault as predicted by Thomas R. Walter et al in there paper. Gravitational spreading and formation of new rift zones on overlapping volcanoes. file:///C:/Users/j16mobile/Documents/gaysail/Blogs/Hawaii/Seismographs/pp1801_Chap4_Denlinger.pdf

I updated the page to eliminate the term "Great Crack". Further I added more description as to what a listic fault looks like and a slump.

One thing I noticed is that the crack in question stopped the lava flow from Pu'u O'o. Well, it stopped a section of the lava flow and it is obvious that lava must have poured into the crack.

....
terracore Thanks for the reference to the koa'e fault. That is to the North and West of this area. It is closer to the summit and descibed as being extremely seismically active and explains why so many earthquakes are just South of the Summit.

Former Puna Beach Resident
Now sailing in SE Asia
HOT BuOYS Sailing

[TomK]

I would urge MarkD and pbmaise (the latter now joining the fear-mongering crowd on his blog) to understand your thoughts and opinions about a potential landslide on Kilauea's southern flank are in direct conflict with the information USGS scientists have provided, and I know who I trust more.

Please read the article on the HVO home web page that was specifically set up to counter the misinformation that is being spread.

https://volcanoes.usgs.gov/observatories/hvo/

I don't usually copy the text from a whole article due to copyright, but this is a government site and the laws are different. For those still claiming that we might get a massive landslide, please read this:

"Facts on the stability of Kilauea's south flank, past and present.
May 14, 2018

There have been several recent highly speculative stories, rumors and blogs about the stability of the south flank of Kilauea and the potential for a catastrophic collapse that could generate a Pacific-wide tsunami. We wish to put these speculations in their proper context by presenting observations of the current situation and an assessment of past evidence of landslides from Kilauea.

There is no geologic evidence for past catastrophic collapses of Kilauea Volcano that would lead to a major Pacific tsunami, and such an event is extremely unlikely in the future based on monitoring of surface deformation. Kilauea tends to "slump", which is a slower type of movement that is not associated with tsunamis, although localized tsunamis only affecting the island have been generated by strong earthquakes in the past.

The May 4 M6.9 earthquake resulted in seaward motion of approximately 0.5 m (1.5 ft) along portions of Kilauea's south flank as measured by GPS stations across the volcano. A preliminary model suggests that the motion was caused by up to 2.5 meters (8 feet) of slip along the fault that underlies the volcano's south flank, at the interface between the volcano and the ocean floor, about 7-9 km (4-6 mi) beneath the surface. This motion is within the expected range for a large earthquake on this fault. The earthquake was probably caused by pressure exerted by the magmatic intrusion on the south flank fault, following the pattern of past earthquake activity that has been observed during Kilauea East Rift Zone intrusions. A small, very localized tsunami did occur as a result of the fault slip. Similar local tsunamis were generated by past large earthquakes, including the 1975 M7.7 and 1868 ~M8 events, both of which resulted in multiple deaths along the south coast of the Island of Hawai‘i.

Adjustments on the south flank caused another ~9 cm (3.5 inches) of motion at the surface in the day after the earthquake, followed by another 2-3 cm (~1 inch) since May 5. This is higher than the normal rate of south flank motion (~8 cm (3 inches) per year) but is expected as the volcano adjusts after a combination of a magmatic intrusion along the East Rift Zone and a large south flank earthquake. We did observe minor ground ruptures on the south flank, but this is expected given the strength of the May 4 earthquake, and deformation data show that the south flank continues to move as an intact slump block.

Geologic history combined with models of south flank motion suggest that the likelihood of a catastrophic failure event is incredibly remote. There are certainly signs on the ocean floor for landslides from other volcanoes on the Island of Hawai‘i and from other islands, but none are associated with Kilauea. In addition, Kilauea has experienced much larger earthquakes and magmatic intrusions in the recent past. The large earthquakes of 1975 and 1868 were not associated with significant south flank landsliding, nor were major East Rift Zone intrusions in 1840 and 1924."

[MarkD]

"I would urge MarkD and....to understand your thoughts and opinions about a potential landslide on Kilauea's southern flank are in direct conflict...."

Sure. Thanks. I am definitely in the novice category. I remember reading about the historic slumps around undersea Hawaii and hearing of the crack prompted my post. A question, essentially.

The link from Glinda is informative.

In any event, geologic time frame on any such events around Hawaii is extreme...

[TomK]

Slumps aren't the same as landslides.

[Obie]

Here is a myth busting article from National Geographic :

https://news.nationalgeographic.com/2018...d-science/

[TomK]

Good article. Short, succinct and accurate. Thank you. Shame it didn't mention PGV.

[MarkD]

"Slumps aren't the same as landslides."

Apparently some sources define a slump as a type of a landslide:

"Landslide is a general term used for a variety of landscape processes including slumps, rockfalls, avalanches, debris flows, mudflows, and lahars. "

http://geologycafe.com/landslide/types.html

But perhaps underwater the definitions differ.