From: gerard@caliban.soest.hawaii.edu (Gerard Fryer)
Newsgroups: sci.geo.geology
Subject: Re: Tsunamis..how far inland?
Date: 28 Sep 92 19:39:14 GMT
Organization: Scum Of the Earth and Senile Tenured

In article <1992Sep24.214012.5367@nntpserver.chevron.com>, hrgmi@seashell.chvpkh.chevron.com (Bob Mitchel) writes:
|> In article <1992Sep17.015758.8196@news.Hawaii.Edu>, 
|> gerard@caliban.soest.hawaii.edu (Gerard Fryer) writes:
|> > that is nothing to sneeze at!!).  How far these things run ashore will
|> > depend on the local topography.  Pig farms almost a kilometer from
|> > shore in Kalama Valley on Oahu (yup, the same valley now stuffed full
|> > of expensive homes) were destroyed in the tsunami from the 1960 Chile
|> > earthquake.  The tsunami inundation map in the Honolulu phone book,
|> > however, shows the inundation zone extending only about
|> > half-a-kilometer inland for that coast.
|> > 
|> 
|> I think you have confused your facts here - the 1960 Chilean earthquake 
|> tsunami did not affect Oahu that significantly.  I lived in Hilo at the time 
|> and saw the town waterfront destroyed with over 60 people killed.  I remember 
|> that other islands reported much smaller wave heights.  However the April 1 
|> 1946 tsunami which originated in the Aleutians may have hit Kalama valley 
|> severely, coming as it did from the north.  I heard wave heights of over 50 
|> feet were reported on parts of the Big Island for that tsunami (such as 
|> Waipio Valley).
|> 

No doubt you are right.  The only first-hand information I heard about
1960 (I first came here a few years later) was flooding of homes on
Wailupe peninsula (a filled-in Hawaiian fishpond).  Houses there showed
a mudline somewhat less than two meters above sealevel but the houses
themselves stood - hardly consistent with a damaging wave coming ashore
at Kalama, although the direction is different.

|> > 
|> > I have always been amazed by how little the people of Hawaii understand
|> > tsunamis (I guess that's because the last damaging one was in 1960).
|> > People think that a 30-foot wave is just like bigger-than-normal surf
|> > at Waimea Bay.  During the great tsunami scare of 1986 I heard a radio
|> > announcer ask a helicopter pilot "Do you see anything strange on the
|> > ocean?  Do you see any storm surf?"  Fellas, sea level itself is going
|> > to rise by 30-ft.  I hope that now people have had a chance to think
|> > about Hurricane Iniki and its storm surge (about 1.5m in Honolulu -
|> > that was pretty impressive) they have a bit more respect for long
|> > wavelength disturbances in the ocean surface								
|> 	.
|> Maybe the reason the people understand so little is because the educators at 
|> the university (and other places) aren't doing their jobs :-).  

I agree 100%.  As mere scum (non-tenurable, soft-money, pure research)
I have argued repeatedly for a real earthquake seismologist to be hired
to a real faculty position, someone who could take on the public
service and educational aspects of the problem.  But it never happens.
That's why I found myself spending a day in a television studio after
Loma Prieta - the real faculty had basically washed their hands of
their responsibilities.

|> Actually, 
|> having lived there I find the people have a very healthy respect for the 
|> power of nature.  Granted, that is different than understanding the technical 
|> details of long wavelength wave generation and propagation, but I think that 
|> those details are secondary.  The civil defense people, particularly on the 
|> Big Island have been good about educating the public on dangers of lava 
|> flows, tidal waves and now hurricanes.  I remember as a child having tidal 
|> wave drills and monthly testing of sirens in Hilo.  

People on the Big Island do indeed have a healthy respect for the
forces of nature.  Big Island Civil Defense director Harry Kim is worth
his weight in gold to that community (although he is a real pain in the
neck for us university types - he seems to do his darndest to restrict
our access to the volcano, so we have to sneak in under cover of
darkness to show students active eruptions).  If the Big Island did not
have Harry I'm sure the death toll from natural disasters would be much
higher.

|> I wouldn't take some disk 
|> jockey's comments out of context and generalize about the education level of 
|> the Hawaiian people.  

I dunno.  On Oahu, people are much more cavalier than on the Big
Island.  There are so many recent immigrants and so few residents with
a memory of damaging tsunamis that a real calamity is in the making.
During the debacle of 1986 (following an earthquake in the Gulf of
Alaska with magnitude about 7.0) Kalanianaole Highway, one block in
from the ocean and nowhere higher than two meters above sealevel, was
completely choked with stationary traffic at the zero hour.  Had there
been a damaging wave, the death toll on that highway alone might have
been in the tens of thousands.  That was a useful lesson, but Hurricane
Iniki showed that Oahu Civil Defense still has a lot to learn - when
they first tried to light off the warning sirens they didn't work (so
what are they testing at 11:45am on the first working day of each
month???).  It took half an hour more to sort things out and get
current to the sirens.

And if county Civil Defense is bad, State Civil Defense is even worse:
During Hurricane Iniki there was a total breakdown of Civil Defense
communications with Kauai, despite the fact that there was still pretty
solid private communications between ham radio operators.  Hams who
made themselves available to State Civil Defense were completely
ignored as a resource (see Joe Dellinger's postings to
sct.geo.meteorology).  Not reassuring. 

Actually, things are even worse than they seem - State Civil Defense
has a brochure warning people about the dangers of earthquakes on the
"Diamond Head Fault," an entity hypothesized to explain a handful of
weak shallow events for which epicenters are known only to about 30km.
The fault, if it exists, has no tectonic explanation.  In the meantime,
the real danger from local earthquakes - that there might be deep
lithospheric failure events (such as Honomu, Big Island, Ms 6.2, 1973)
beneath any of the islands - is completely ignored, both by Civil
Defense and by academics.

|> However, there is never enough public education about 
|> these things, and as an educator here is an opportunity for you...
|> 

I do what I can, mainly in anticipation of the guilt I'll feel when
faced with the inevitable question "Why didn't you warn us?"  At the
same time I have to accept that any efforts I spend on public service
or education reduce my chances of promotion or of ever gaining a real
job.  But that's a bitch for sci.research.careers, not s.g.g...
-- 
Gerard Fryer  (g.fryer@soest.hawaii.edu)
School of Ocean & Earth Science & Technology
University of Hawaii at Manoa
Newsgroups: sci.geo.geology