From previous studies, we know that Kilauea is the site of an active
landslide, the Hilina slump, which has moved in historic times," said
Julia Morgan, assistant professor of Earth Science at Rice University.
"We now recognize that Kilauea also experienced a catastrophic
landslide in the past, possibly within 25,000-50,000 years, which is
quite recent in geologic terms." And there WERE aboriginal people in
Australia at that time. This is an estimate of habitation, as there is
proof of earlier habitation, but the time frame is not provable:
"Since the excavation of this 5000 year old deposit, archaeological
evidence of habitation in Australia more than 35,000 BP (years before
present) has been found in western New South Wales and in southern
Western Australia. These, and a score of younger sites, illustrate the
wide extent of ancient settlement throughout the Australian mainland
and islands".

Not to mention that a landslide on the Island of Oahu was the largest
in history as written:
Science Daily Ñ HOUSTON, Dec. 8, 2003 -- The Hawaiian Islands are home
to the largest documented shoreline collapse in history, an ancient
seaward landslide that sent rocks from the island of Oahu to sites
more than 100 miles offshore. The avalanche of debris from the
northeast shore of Oahu probably occurred between 1.5 and 3 million
years ago, and it undoubtedly created one of the largest tsunamis in
Earth's history, a wave large enough to inundate every coastline of
the northern Pacific Ocean. There is more, but I have to shovel snow.
The above is possible and very likely to repeat history. It HAS
happened, it is possible, and there is PROOF.

On 2007-02-21 10:48:13 -1000, Peeta <PedroGonzales88@AOL.com> said:

From previous studies, we know that Kilauea is the site of an active
landslide, the Hilina slump, which has moved in historic times," said
Julia Morgan, assistant professor of Earth Science at Rice University.
"We now recognize that Kilauea also experienced a catastrophic
landslide in the past, possibly within 25,000-50,000 years, which is
quite recent in geologic terms." And there WERE aboriginal people in
Australia at that time. This is an estimate of habitation, as there is
proof of earlier habitation, but the time frame is not provable:
"Since the excavation of this 5000 year old deposit, archaeological
evidence of habitation in Australia more than 35,000 BP (years before
present) has been found in western New South Wales and in southern
Western Australia. These, and a score of younger sites, illustrate the
wide extent of ancient settlement throughout the Australian mainland
and islands".

Julie interpreted her seismic reflection data without access to the later
hydrologic and petrologic information on the distal landslide deposits off
Kilauea, which we now suspect are distinct from and underly the deposits
she imaged upslope. I have to check with her about what she thinks now.

There is no known way something as small as the Hilina Slump could produce
an observable tsunami in Australia, especially since a slump (merely
rotational) is far less efficient at generating a tsunami than a debris
avalanche. Okal and Synolakis have multiple papers making this point;
their basic argument is that since a slump is a dipole (a drawdown of
water here, an uplift there), in the far field the contributions from the
uplift and drawdown cancel each other out. The tsunami from a slump is
only large in the near field. Observations of the slump-generated tsunami
off Papua New Guinea in 1998 bear this out.

Not to mention that a landslide on the Island of Oahu was the largest
in history as written:
Science Daily Ñ HOUSTON, Dec. 8, 2003 -- The Hawaiian Islands are home
to the largest documented shoreline collapse in history, an ancient
seaward landslide that sent rocks from the island of Oahu to sites
more than 100 miles offshore. The avalanche of debris from the
northeast shore of Oahu probably occurred between 1.5 and 3 million
years ago, and it undoubtedly created one of the largest tsunamis in
Earth's history, a wave large enough to inundate every coastline of
the northern Pacific Ocean. There is more, but I have to shovel snow.
The above is possible and very likely to repeat history. It HAS
happened, it is possible, and there is PROOF.

Superlatives like "largest in history" drive geologist up the wall, since
history only goes back a few thousand years. Better to say "The largest
known landslide on the face of the Earth." [Even that is not strictly
true, since there is a larger slide off the northeast side of the Ontong
Java Plateau, the OJP slide has yet to be described in a publication,
however.]

The inference that the tsunami from the Nuuanu Slide was large on every
shoreline of the Pacific is not accepted by modelers. Kenji Satake
computed a maximum runup along California shorelines of 30 meters, but he
did not include dispersion in his modeling, so that is an upper limit.
Just like the Canaries, the tsunami wavelength would be less than ten
times the water depth, so the tsunami would be highly dispersed; many
modelers would reduce Kenji's maximum runup for California to less than 10
m, with most of western North America seeing about 2 m (even that is not
as bad as it sounds, since the predominant period would be ten minutes or
less). Everyone agrees that the tsunami must have been negligible in the
southern or western Pacific because the source was so directional.

But the Nuuanu Slide is a red herring: Oahu is now pretty much dead and
will not produce any more such features. A far greater hazard is the one
posed by the western flank of Mauna Loa, which has produced five great
landslides in the last half-million years. But again, the hazard is well
known and widely discussed (and was made the finale of National
Geographic's "Ultimate Tsunami"). Nobody has yet gone through the
probabilistic hazard assessment necessary to put that hazard in
perspective with other competitors for disaster funding (hurricanes,
earthquakes, floods, earthquake-generated tsunamis, etc.). It will be
done, though.

-Gerard
[personal views only; the views expressed here are not necessarily those
of the U.S. National Oceanic and Atmospheric Administration.]

"Gerard Fryer" <gerard@NUTShawaii.rr.com> wrote in message
news:45dcdb66$0$28120$4c368faf@roadrunner.com...

snip>> [full message below my sig - mw]

"Nobody has yet gone through the
probabilistic hazard assessment necessary to put that hazard in
perspective with other competitors for disaster funding (hurricanes,
earthquakes, floods, earthquake-generated tsunamis, etc.). It will be
done, though."

Thanks for your further clarifications, Gerard. Prominently absent from your
list of competitors for funding is a large meteoritic impact into the
Pacific basin. I've read that that scenario represents the greatest
actuarial yearly natural hazard risk for those living on the Pacific rim.
The rarity of the event is more than compensated for by its huge projected
death toll. I may not have expressed it correctly, in terms a statistician
would use. Do you concur with that assessment, or the somewhat more general
one that a large meteor impact anywhere on the globe represents the highest
risk (yearly likelihood X death toll) to all of this plantet's inhabitants?
As of a couple of years ago, the total number of people working on the
project to identify such a threat, and/or counter it, worldwide, was
described as "fewer than the number of people employed at one large
McDonald's outlet."

Also, Gerard, what is your title at the Pacific Tsunami Warning Center?

On 2007-02-21 17:21:49 -1000, "Mike Williams" <miklwlms@pacbell.net
said:


"Gerard Fryer" <gerard@NUTShawaii.rr.com> wrote in message
news:45dcdb66$0$28120$4c368faf@roadrunner.com...

snip>> [full message below my sig - mw]

"Nobody has yet gone through the
probabilistic hazard assessment necessary to put that hazard in
perspective with other competitors for disaster funding (hurricanes,
earthquakes, floods, earthquake-generated tsunamis, etc.). It will be
done, though."

Thanks for your further clarifications, Gerard. Prominently absent from
your
list of competitors for funding is a large meteoritic impact into the
Pacific basin. I've read that that scenario represents the greatest
actuarial yearly natural hazard risk for those living on the Pacific
rim.
The rarity of the event is more than compensated for by its huge
projected
death toll. I may not have expressed it correctly, in terms a
statistician
would use. Do you concur with that assessment, or the somewhat more
general
one that a large meteor impact anywhere on the globe represents the
highest
risk (yearly likelihood X death toll) to all of this plantet's
inhabitants?
As of a couple of years ago, the total number of people working on the
project to identify such a threat, and/or counter it, worldwide, was
described as "fewer than the number of people employed at one large
McDonald's outlet."

There is a growing awareness that the tsunami hazard from an asteroid
impact is something that needs to be taken seriously. A few years ago
Ward and Asphaug published an asssessment of the probabilistic hazard; it
has taken until now for people to work through their paper--I'm still
mulling over it myself.

The expected flux of Earth-crossing asteroids is very earthquake-like in
that it should follow something like the Gutenberg-Richter relationship
(i.e., lots of small ones, fewer big ones). We already know that incoming
bolides produce upper atmosphere explosions of a megaton or larger a
couple of times each year, so the odd impact tsunami must exist in the
historical record. So far none has been convincingly identified, however.
In our spare time a couple of us are looking at how to incorporate
infrasound array data from the International Monitoring System of the
CTBTO into our routine processing so we could identify an impact (and
perhaps get out a tsunami warning) in real time. This work is in its
infancy, so it will be a while before we have anything to report.

While the number of academic and NASA people funded to work on the hazard
posed by near-Earth objects is probably comparable to the number of
employees of a large McDonalds, there are many volunteers associated with
the various Spaceguard projects around the world. There is another major
player, too: the U.S. Air Force. As part of the U.S. involvement in the
Comprehensive Test Ban Treaty Organization, the Air Force faces the task
of rapidly differentiating bolide explosions from atmospheric nuclear
tests. And the Air Force Space Command has the rather daunting
responsibility of protecting the Earth from asteroid impact. You can be
sure that USAF has a lot of people working on the problem.


Also, Gerard, what is your title at the Pacific Tsunami Warning Center?

Geophysicist.

-Gerard
[personal views only; the views expressed here are not necessarily those
of the U.S. National Oceanic and Atmospheric Administration.]