The Burma plate is often referred to as a silver plate formed by way of strain partitioning mechanism. Why is a Burma plate called a silver plate?
I think you mean sliver plate (not silver). It is a small plate, generally much longer than it is wide (hence a sliver), wedged between major plates, as a result of strain partitioning. For example, oblique strain at a convergent boundary between two major plates often gets partioned into a component normal to the boundary (leading to pure thrusting), and a component transverse to it, leading to strike slip deformation. If these different directions occur along major plate bounding faults, the area in between forms a sliver plate. In the case of Burma, the major plates are the Indian plate and the Eurasian plate but the tectonic situation is there is also strongly influenced by the Andaman sea oblique spreading system.
Subduction at the Burma Arc is very oblique. It is partly partitioned by Sagaing Fault taking up about 1/2 of strike slip component. Thus the long narrow sliver between the subduction zone and the Sagaing Fault is moving differently from either India or Asia