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Re: More questions on the Burma microplate (allegedly where the quake occurred)
Ok, now I don't mean to sound rude but have you tried Google? I typed in
"burma microplate" both with and with out the quotes and got a whole slough
of hits. Most useful were the alternative keywords I came up with simply by
reading the headers. For instance I got Burma block and Burma Plate,
Malacca-Burma block, West Burma Block. I could probably come up with more if
I searched harder. Anyway I eventually came across a blog which had pictures
and I traced them back to the source, and voila:
----- Original Message -----
From: "Dora Smith" <firstname.lastname@example.org>
To: "Dora Smith" <email@example.com>; "DML" <firstname.lastname@example.org>
Sent: Friday, December 31, 2004 10:52 PM
Subject: Re: More questions on the Burma microplate (allegedly where the
> John Milson, in a chapter for a forthcoming book on Sumatra,
> http://www.es.ucl.ac.uk/people/milsom/smtrntct.htm, doesn't mention the
> Burma plate either - or the Sunda plate, atleast by name.
> He says that the fault-ridden zone between the Java trench and the Sumatra
> Fault, which he calls the forearc region, must be separated from both the
> "Indian Ocean" and "Eurasia". He says it is often called a sliver plate
> but to call it a plate suggests that it has a degree of "strength and
> rigidity" that the long and narrow strip does not have. He also says
> any analysis of subduction beneath Sumatra must take into account the
> probability of independent movement of fragments in this zone.
> We have another academic geologist who appears not to have heard of a
> I wonder what these two would say if I contact them, tell them to look at
> those NEIS web pages, and ask what's the Burma plate? I think I'll try
> it. (Grin)
> So is the forearm strip the same thing as the "Burma plate"?
> Dora Smith
> Austin, Texas
> ----- Original Message -----
> From: "Dora Smith" <email@example.com>
> To: "DML" <firstname.lastname@example.org>
> Sent: Friday, December 31, 2004 8:50 PM
> Subject: More questions on the Burma microplate (allegedly where the quake
> > Most ot what I'm finding on the Burma microplate is confusion. Someone
> > sent me a bunch of links he thought would help; one link doesn't work,
> > is to that ol' NEIS chart, and the others are to small textual
> > of the plate.
> > I have Danny Hilman Natawidjaja's 2002 dissertation, "Neotectonics of
> > Sumatran Fault And
> > Paleogeodesy of the Sumatran Subduction Zone" , at
> > esis.pdf.
> > Natawidjaja identified and mapped every fault on the island of Sumatra
> > between the Sumatra fault and the subduction trench. He discusses all
> > the geologic features. He never mentions a Burma plate. He doesn't
> > it doesn't exist; he literally never mentions it, though his work is
> > extremely recent. I'd call that a good argument to think that many
> > geologists would have as little idea as I do what the NEIS descriptions
> > the earthquake are talking about.
> > Natawidjaja does mention an outer arc sliver, and describes it as a
> > piece of plate - is that the same thing as this Burma plate?
> > Apparently the answer to the question about what is sliding in relation
> > what, is that, actually, the plates aren't sliding in a direction
> > to the subduction fault, at the trench, nor along one fault between two
> > plates; nor along two faults between three plates. The two plates
> > converge in a very oblique angle. Like apparently most oblique
> > faults, the subduction trench takes perpendicular motion and a complex
> > lacework of strike/slip faults between the trench and the central ridge
> > motion parallel to the subduction trench. In the case of the Sunda/
> > subduction faults, a lacework of faults large and small between the
> > and the Sumatra fault in the central mountain range take the motion
> > to the trench.
> > Natawidjaja appears to suggest that more of the motion is absorbed off
> > the coast of Sumatra than on Sumatra, but I'm not very clear on that
> > I've only read two chapters of his long thesis so far. He explains
> > one reason to believe that only so much displacement has occurred on the
> > island of Sumatra since it began only a few million years ago, is that
> > rest of it occurs offshore.
> > The Burma plate is supposed to be separating from the Sunda plate.
> > Natawidjaja's version of that is that there is spreading occurring at
> > various places on the island of Sumatra and between the island and the
> > subduction trench, and that the spreading increases in the Andaman Sea
> > the north.
> > North of Sumatra, the north-south aspect of the oblique convergence of
> > plates is handled by a network of faults in the Andoman Sea and a major
> > fault in Burma.
> > Natawidjaja does not mention a Sunda plate, either.
> > I am also partway through the Hall article - so far he mentions the
> > plate but does not properly discuss it. He appears to be far less
> > interested in teh details of what is taking place than Natawidjaja is.
> > Does anyone have any ideas?
> > Is there anything about the boundaries of the Burma plate that would
> > me to identify its boundaries on a detailed chart of the faults of the
> > By the way, since all of the faults between Sumatra and the subduction
> > trench have been mapped within the past few years, it should not be
> > difficult for the NEIS to identify the fault that was affected.
> > Their explanation of the quake makes less sense than ever; there are no
> > faults in the area where sections of crust move longitudinally along a
> > and thrust upward. The thrust upward part and the move longitudinally
> > part are the work of different faults. Conceivably a piece of land
> > have moved upward if a new fault were created and a piece of land that
> > been held down bounced up, but again NEIS's explanation does not say
> > happened.
> > Certainly if they could tell us so much as they did they ought to be
> > identify the fault - particularly if it is a preexisting fault 600 miles
> > long. Only one fault on Natawidjaja's chart appears to be a
> > That would be the West Andaman fault. The chart does not show whether
> > West Andaman fault is 600 miles or more long; but it is the only fault
> > exists in the area wehre the epicenter of the quake was, that extends
> > the northern edge of the chart, and its name suggests that it must
> > for some distance in the Andaman Sea. There is also something funny
> > how Natawidjaja has it labelled. What is a nomocline fault? He also
> > syncline faults and anticline faults, those terms refer to two sides of
> > hill in a folded area; does a nomocline fault also have something to do
> > moving up and down?
> > Yours,
> > Dora Smith
> > Austin, Texas
> > email@example.com