🚀 go-pugleaf

In article <1992Aug3.192912.16174@acc.com> art@acc.com (Art Berggreen) writes:
>In article <1992Jul24.173220.21793@hellgate.utah.edu> tolman%asylum.cs.utah.edu@cs.utah.edu (Kenneth Tolman) writes:
>>
>>  I am wondering if there is some autocatalytic element in earth-quakes. 
>>That is- does the beginning of a slippage induce further slippage by
>>reducing friction or through some other mechanism?  Is the quake self
>>amplifying- and is that why they occur with tremendous energy rather than
>>as a series of small imperceptible quakes?
>>
>>  Is there any sort of amplification process in this deal?  (The implication
>>being that earthquakes may indeed be truly unpredictable)
>
>There are areas where the fault motion tends to be a sequence of very
>frequent but small quakes (e.g. Hollister, CA.).  Where the big quakes
>happen are areas where the faults are "locked", but the landmasses on
>either side are still moving.  This causes stress to build up in the
>rocks until something gives.  Like most materials, once a crack starts,
>this forms a region of intense stress which will propagate the crack.
>Then the fault will tend to move until most of the stress is gone.
>As the fault settles into its new configuration, more slippages occur
>as the stress patterns "settle down" (aftershocks).
>
>Art

Did anyone here read the Bak and Chen (please forgive me if I got that wrong)
article on self-organizing criticalities?  They suggested that in large dynamic
interactive systems (such as tectonic plates, snow banks, and even games of
Life) a state of criticality will tend to occur.  The criticality may respond
to stimuli in ways ranging from the undetectable to the catastrophic (it may
take a single snow flake to start an avalanche!).  It was in (I'm embarassed to
say, but I can't get Nature) Scientific American.  What happened to the theory?

Richard