Liquefaction assessment of sand in sequenced earthquake motions was studied based on two series of stress-controlled, undrained hollow cylinder cyclic torsional shear tests. A high risk of liquefaction is expected under such conditions because of the accumulation of excess pore pressure by multiple seismic motions. The specimen with the residual excess pore pressure was exposed to various aftershocks that are
(i) staged wave loading and
(ii) irregular wave loadings with various waveforms and durations.
The results of two loading tests are combined to draw a chart that tells the possibility of liquefaction depending on the level of the excess pore pressure remaining in the ground.