waves through the material and further prevents the failure of the trench walls application_number US 31482381 A description referring first to fig1 a fault 2 extending from the ground surface 4 downwardly through earth crust 6 is located some distance from a structure 8 such as a nuclear power plant on the ground surface it is assumed that an earthquake occurs at a hypocenter 10 at a location which is at some depth below the ground surface the epicenter of the quake is that point 12 on the ground surface which is vertically above the hypocenter and in the illustrated example it is spaced some distance from the power plant when the earthquake strikes seismic waves 16 namely p and s waves radiate from the hypocenter in all directions including along radiant 14 a straight line which connects the hypocenter with the power plant in this idealized case s and p waves striking the ground surface generate surface waves 18 which travel along the ground surface away from the epicenter at point 12 located on the ground surface a seismic shield 20 see fig2 constructed in accordance with the present invention is a 34 wall 34 of a material 36 see fig5 which does not transmit seismic waves especially the s waves and which is disposed in a trench 22 located between the power plant 8 and the fault 2 the trench.