Hawaiian Geology

[lensperson]

Re: Hawaiian Geology

This just in.
From www.nupepa-hawaii.com !
Jan 5, 2012.

SNOW on Hualai , a hundred and one years ago,1911.

'On thursday, the fifth of this month,snow was seen lying on the summit of
Hualalai ; for a long many years this is the first time snow has been seen again
on this mountain ; it is something novel for the people of Kona '
from Aloha Aina 1/7/1912,p.1

[lensperson]

Re: Hawaiian Geology

In chapter 25 of Isabella Birds letters is an intriguing comment.
" It has been said and written that there are no steam-cracks or similar traces of
volcanic action on Mauna Kea,but in several fissures I noticed ferns growing
belonging to an altitude 4000 feet lower and on putting my arm down found a
heat which compelled me to withdraw it.
As the sun rose these cracks steamed in all directions"

[Kaonohi]

Re: Hawaiian Geology

An interesting show was on the History Channel a few nights ago, dealing with the 'underground' tunnels on Easter Island.

There were three volcanoes on the main island, and underground pyroclastic flows left numerous lava tubes, which were exploited by the Polynesian inhabitants for homes and shelter. I missed most of the show, unfortunately, but it was shown that these lava tubes were used for residence, shelter, hiding from invaders, and burials. Many hearths, i`iwi, and petroglyphs have been found and are currently being cataloged.

I wonder of our Hawai`i has similar extensive features? I know of some small,short lava tubes and caves, but nothing like the miles-long features on Easter Island.

[Kalalau]

Re: Hawaiian Geology

Another interesting feature of Hawaiian geology is the landslides. Basically any time you see a steep pali, you can be pretty sure there has been an enormous landslide in the area. At p. 39 in the 3d edition of the Atlas of Hawai'i 17 big landslides are identified. Fortunately they are infrequent, only every 100-200 thousand years. At some point I heard about sea floor deposits on top of Lana'i, proof of the height of related tsunamis. What of the Great Crack on the Big Island? Will it be a sudden disastrous slide or a slow harmless slump, or maybe nothing at all.

[D'Alani]

Re: Hawaiian Geology

This is an interesting point because I believe that is why the windward side of the Koolau's appear the way they do. I always thought it was formed by the prevailing trade winds over the hundreds of years when in fact it is due to an enormous landslide way back when.

[Kalalau]

Re: Hawaiian Geology

More info on Hawaiian landslides, www.mbari.org/volcanism/Hawaii/HR-Landslides.htm

[lensperson]

Re: Hawaiian Geology

The direction of the trade winds is very important in the understanding
of the history of the Islands.
On the Big Island some of the last flank eruptions on Mauna Kea have large
debris fields resulting from light pumice ash clouds.
The direction those fields spread shows the overall wind pattern at that
portion of time

[Kalalau]

Re: Hawaiian Geology

Friends who lived in Hilo during the 1984 co- Mauna Loa-Kilauea eruptions swore this happened: a ball of light came out of Kilauea and settled into the crater of Mauna Loa, which then began its eruption. There are things that tax your credulity, there is mass hysteria, but there are also things that happen that just can't be explained. Has anyone else heard about that phenom?

[lensperson]

Re: Hawaiian Geology

Ball lighting is a strange phenomena.
When I was a small child my family lived on a small key
in the southern tip of Florida.
Each afternoon thunderstorms came and went.
One day the air pressure grew low and the television set started to
make smoke.
A few moments later a small orb of something sailed into the small living room
spun around and then fizzled out.
Ball lightning is real I've seen it.

[Amati]

Re: Hawaiian Geology

Another interesting feature of Hawaiian geology is the landslides.

I saw the SHINKAI 6500 on a tour:

The submarine geology of the Nuuanu (perhaps the largest landslide in the world) and Wailau landslides was investigated during 1999, using the SHINKAI 6500 manned submersible and its mother ship, R.V. YOKOSUKA. Observations were made at eight dive sites, and about 100 in-situ rock samples were collected from the landslide deposits at depths of 2500 to 4500 meters.

The Hono Advertiser reported: "The extent of the Nuuanu slide is impressive", and continued "a single block of rubble known as the Tuscaloosa Seamount stretches 13 miles wide by 17 miles long, the size of Lanai".

A crewman gave us small piece from a slide, collected at 4,000+ meters. How cool is that!

[Kaonohi]

Re: Hawaiian Geology

OK..... Please inform us.... do we have a major landslide event in our near future????????????????????????

Where should I run to???

I saw the SHINKAI 6500 on a tour:

The submarine geology of the Nuuanu (perhaps the largest landslide in the world) and Wailau landslides was investigated during 1999, using the SHINKAI 6500 manned submersible and its mother ship, R.V. YOKOSUKA. Observations were made at eight dive sites, and about 100 in-situ rock samples were collected from the landslide deposits at depths of 2500 to 4500 meters.

The Hono Advertiser reported: "The extent of the Nuuanu slide is impressive", and continued "a single block of rubble known as the Tuscaloosa Seamount stretches 13 miles wide by 17 miles long, the size of Lanai".

A crewman gave us small piece from a slide, collected at 4,000+ meters. How cool is that!

[Kalalau]

Re: Hawaiian Geology

Not likely in the near future but it will happen again. They seem to happen only once every 100 or 200 thousand years so odds of one happening during our lifetimes are fantastically small. Where to go if one happens? Very high. An airplane would do it, just stay up for a while and everything would be fairly normal given you could find a place to land. Geologists also are concerned about a volcano in the Canary Islands that could lose a flank and send a tsunami toward the east coast of North America. That coast, being fairly flat, would suffer a lot of damage while the west coast's mountains would probably bounce tsunami waves from Hawai'i or elsewhere back out to sea.

[lensperson]

Re: Hawaiian Geology

The Mystery of the Three caves
The name Keanakolu means just that.
The few lava caves of Mauna Kea and Hualalai are another rarity.
The carvings in wood found there are truly astonishing.
From what model could those carvers have created these sculptures?

[Kalalau]

Re: Hawaiian Geology

There was a survey on the safest states from the natural environment viewpoint, Hawai'i was rated the safest state. Makes sense. Not many blizzards, tornados probably happen but very rarely, hurricanes unfortunately do happen but are pretty rare, the earthquakes (olai) mostly have been pretty mild, the volcanos do not explode, there are big storms but not usually violent like something you'd see in New England. Of course I don't remember the source, it was something like the history channel, reasonably reliable I guess. So insurance rates should reflect the lower risk and lower loss.

[GeckoGeek]

Re: Hawaiian Geology

So insurance rates should reflect the lower risk and lower loss.

I'm not so sure about that. Safety and property loss are two different things. Some of the biggest threats to Hawaii are hurricanes and tidal waves. In most cases, we have an adequate warning system to allow us to seek safe shelter.

A quick look at what happened to Kauai shows the difference. Few deaths, but plenty of property damage.