[Geysers] New Zealand

[Ron Keam]

The Christchurch earthquake:

I have heard nothing about any sympathetic activity between the 
earthquake and the hot springs of the Taupo Volcanic Zone.  This is 
not too surprising since the distances are considerable.  To give 
some idea, the distances from Christchurch to a few places are: 
Wellington 200 miles, Ruapehu 350 miles, Rotorua 450 miles.  Ruapehu 
is tne nearest active volcano to Christchurch.

Friends in Christchurch have sent some photos of effects around their 
house.  The most obvious phenomenon was the eruption of sand from the 
sediments on which the house is built having become slightly 
fluidised by the shaking.  This seems to have been a fairly 
widespread effect in the city.  Also my friends' lawn has been 
rumpled into slight ridges and troughs.  No structural damage was 
sustained by their house although many ornaments and books were 
thrown down.

Canterbury University (Christchurch) has been closed for a few days. 
Their main library shelves were toppled and some damage has occurred. 
Estimates of the total monetary cost in Christchurch are around $NZ2 
billion.

The most amazing thing is that there were no fatalities and only a 
couple of people sustained serious injury.

Aerial and ground photographs show a very large number of rifts along 
what clearly is the main fault line.  This feature had not been 
recognised there before and indeed it might be an entirely new 
manifestation.  The fact that in places there are a number of closely 
spaced rifts suggests there might have been en echelon movement, but 
if that were the case I would have expected them to be at an angle to 
the main fault direction and such an orentation effect is not obvious.

At magnitude 7.1 this is stated to be the eighth strongest earthquake 
to have been experienced in New Zealand since records began.  The 
somewhat stronger Napier earthquake of 3 February 1931 had the 
greatest loss of life with 256 deaths.  For comparison wiith other 
New Zealand natural disasters the Tarawera eruption caused about 120 
deaths, the Tangiwai railway disaster (when the Ruapehu crater lake 
burst out and caught a crowded express train on 24 December 1953) 
caused 151 deaths (including that of one school friend of mine). 
Since records began New Zealand has so far escaped significant 
tsunami damage and casualties (but we are all aware of that hazard as 
being very real considering the tectonic setting of the country).

If I do learn of reactions having occurred in the hot spring 
activities I shall inform the list in due course.

Ron Keam

>Greetings and Salutations,
>
>I know we have a few people on the web server in New Zealand, so I 
>hope everyone made it through with minimal damage.  I was also 
>wondering if there was any noticable change in the geyser activity 
>noted post quake?  >From hallf a world away, it appears this could 
>be a situation much like the Hebgen earthquake or Borah Peak quake.
>
>Thank you for any info,
>
>Stephen Eide
>
>Content-Type: text/plain; name="ATT00001..txt"
>Content-Description: ATT00001..txt
>Content-Disposition: attachment; filename="ATT00001..txt"; size=218;
>	creation-date="Tue, 07 Sep 2010 14:33:42 GMT";
>	modification-date="Tue, 07 Sep 2010 14:33:42 GMT"
>
>Attachment converted: Macintosh HD:ATT00001. 5.txt (TEXT/ttxt) (004975DE)

-- 


#####################
Ron Keam
The Physics Department
The University of Auckland
Private Bag 92-019
Auckland
New Zealand
Phone +64 9 373-7599 extension 87931
FAX +64 9 373-7445
EMail r.keam at auckland.ac.nz
#####################