From: Kay Wyatt 
To: psnlist 
Sent: Sun, 17 Mar 2013 23:48
Subject: Re: Oregon Coast USA -Tsunami Risk


This publication shows earthquake potential along the Oregon Coast
http://www.oregongeology.org/sub/quarpub/CascadiaWinter2010.pdf
Notice especially the Cascadia earthquake timeline for the last 10,000
years on the bottom of page 8.

This publication talks about the similarity of the Oregon Coast to that
of the Japanese Coast
http://www.oregongeology.org/pubs/cascadia/CascadiaWinter2012.pdf

Kay Wyatt

Hi Kay,

      Reading through the articles makes me mighty glad that I DON'T
live on the Oregon Coast ! The Coast Highway looks very vulnerable.
    Do you have a strong motion seismic monitor / detector, yet ?
    How about life jackets and all terrain cross country "escape" motor
bikes ??? Just 20 minutes to get to high ground is NOT very long!
Looking at the map of Depoe Bay, there seem to be some reasonable
hills that you could "escape to".
    But the geologists seem to have made an assumption as to how big
any future tsunami is likely to be (which is carefully NOT mentioned!).
Presumably, this is based on some sound measurement - like the
previous tsunami inundations in river valleys ?
    With what accuracy can you measure how the land levels have
changed over the millennia ?
        Are they calculating for the largest tsunami on record and with=20
what
'safety margin', or on the average, or what ? Supposing that either the
next tsunami is bigger that the previous ones, or that the geologists
have got their rather difficult historical calculations of earthquake
magnitudes and tsunami flooding a bit wrong ? What sort of safety
margin has been 'built in' ? If any ?

    Regards,

    Chris Chapman



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