I am concern about the lateral displacement of this bullet tank under an earthquake. I looks like tank will be still buried,though marginally, in order to have a lateral displacement lower than one inch. Your input is appreciated.
Geotechnical is not my field, however, if you are concerned about movement, about using flexible connections similarly to what is being done with bulk storage propane tanks.
I think that the possible slide you are showing may not affect the stability of the tank since it appears that the soil in the slope is for protection and not for tank support. Perhaps a combination of the movement of the fluid inside the tank and the slope failure may trigger lateral movement of the tank. You may need to add the lateral force of the fluid due to its movement in your seismic slope stability analysis. I am not sure how to quantify that force but google may show some information.