  When compressed frictional granular media are decompressed, generically a
fragile configuration is created at low pressures. Typically this is
accompanied by a giant frictional slippage as the fragile state collapses. We
show that this instability is understood in terms of a scaling theory with
theoretically computable amplitudes and exponents. The amplitude diverges in
the thermodynamic limit hinting to the possibility of huge frictional slip
events in decompressed granular media. The physics of this slippage is
discussed in terms of the probability distribution functions of the tangential
and normal forces on the grains which are highly correlated due to the Coulomb
condition.
