Ahhh but you have to remember this event was very shallow  !!  :)
only 20 - 30 km deep, very crustal. It was nowhere near deep enough for the
plasticity effects to be a factor.

cheers
Dave


At 03:58 AM 18/03/2011, you wrote:
>Hey Dave,
>
>Thanks for your explanation and response.
>
>I believe I understood the fundamental and distinguishable concepts between
>subduction quakes and transform ones but wasn't certain why megaquakes can
>happen along these subduction boundaries if theoretically, there's enough
>heat there to keep the material "plasticy" and less brittle than the more
>shallower strike slip zones.
>
>
>
>
>-----Original Message-----
>From: psnlist-request@.............. [mailto:psnlist-request@...............
>On Behalf Of Dave Nelson
>Sent: Tuesday, March 15, 2011 4:02 AM
>To: psnlist@..............
>Subject: Re: Subduction zone quakes...
>
>Hi Kareem,
>                   ohhh gosh, where do I start  :)    Oh... Maj
>M7.5+  events are NOT restricted
>to subduction zones  :)  Think of the big ones in SW Missouri, New Madrid,
>1811-1812; Lisbon, Portugal 1755, M8.7  some of the large  M7.9 or so
>ruptures of the San Andreas fault.
>
>ok some differences (and others can chime in with ones I forget about)......
>
>1) The focal mechanism are very different to strike-slip faults  have a look
>at the brief explanation on my www page...
>http://www.sydneystormcity.com/fomec.htm
>It is a direct result of these types of motions that give rise to tsunamis
>that wouldnt be created by a strike slip motion on the seafloor.
>
>2) The quakes can be VERY deep. It is relatively rare for strike slip events
>to be deeper than ~ 50km. Whereas subduction events can be as deep as 650km.
>Have a look through the USGS records for events in the Kermadec to Fiji
>region, north of New Zealand ( and even under the North Island of NZ)
>     The reasons for the causes of the really deep subduction events is quite
>amazing.....
>In regions as mentioned in previous paragraph, the seafloor is subducting so
>fast in that region, it gets very deep before its core becomes "plastic" and
>starts to melt all the way through.  That is the core can still be cold have
>brittle failure whilst the outer layers of the
>   subducting slab is virtually molten.  Plate motion rates are in excess of
>8cm / year as they are off the east coast of Japan.
>
>ok there's a little morsel for you to chew on for a start  :)
>
>cheers
>Dave
>Sydney
>
>
>
>At 11:48 AM 15/03/2011, you wrote:
> >Aside from the large magnitude (i.e. M8.0+) What's the difference
> >between these subduction zone events and events along a transform plate
>boundary?
> >Kareem
> >Elk Grove, California
>
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