Part 4 – Problem 04: As our National Code and Eurocode show little resemblance than ASCE, could you provide us some supplementary information about ‘others’ category?( what is the precise meaning of grid/slab/fault etc.)

These are all potential seismic sources that are mapped and considered in the hazard calculation. Interface and slab (sometimes labeled intraslab) sources indicate the location of a source relative to a subduction zone. Faults represent seismic sources from known or mapped faults. Grids indicate potential background seismicity not related to a known fault, and use an algorithm to smooth this data over gridded coordinates.

Details regarding gridded seismicity can be found here:
Frankel et al. (1996). “National Seismic-Hazard Maps: Documentation.” Open-File Report 96-532, Denver, CO. June 1996