Alan and Jocelyn Munro wrote:

> Following the Fiordland MI 6.2 quake in South Island New Zealand I have
> recorded 18 aftershocks from the area. One of my school students noted that
> many of the aftershocks occured as pairs ( about 5 pairs) separated by about
> 1 minute. See example of 5 Nov.
> Has anyone else noticed this phenomena and what could be causing this.
> Alan Munro
> Invercargill

Alan,
   This sounds quite interesting.  It would be cool to see a plot of the time
line of these aftershocks to put it all into perspective.  Also, if the
locations
are available it would be cool to see "pairs" plotted on a map (maybe
distinguishing different pairs by a given color or symbol).  This almost
seems like a case for triggering...if that were so then I might guess that the
second aftershock in the pair sequence was occurring in a very focused
area.  If you have the data, but not the plotting tools, maybe you can send
the data to me and I can throw together a couple of gifs to post on the web.

Cheers!


John Hernlund
Department of Earth and Space Sciences
University of California, Los Angeles
hernlund@............

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