Though　seismic　hazards　are　infrequent,　their　occurrence　can　lead　to　severe　destruction.　To　understand　how　lowprobability,　high-impact　seismic　hazards　would　affect　the　stability　of　integrated　energy　systems　(IES),　this　paper　develops　a　seismic-resilient　integrated　energy　system　(SRIES)　design　optimization　model.　The　model　employs　a　bi-level　Monte　Carlo　method　to　capture　the　low　probability　of　seismic　scenarios,　monetize　the　hazard　damage,　and　stochastically　optimize　IES　design　and　operation.　A　representative　case　study　in　Fujian　Province,　a　region　frequently　affected　by　seismic　activity　in　the　Taiwan　Strait,　reveals　that:　(1)　incorporating　seismic　hazards　into　IES　design　leads　to　a　2%　increase　in　net　present　cost,　with　98%　of　this　increment　attributed　to　hazard-induced　unmet　energy　demands;　(2)　as　the　resilience　requirement　increases,　the　investment-effectiveness　for　resilience　reinforcement　initially　rises　and　then　declines,　indicating　a　clear　turning　point　between　the　costs　of　resilience　reinforcement　and　its　associated　benefits;　(3)　among　all　technologies　within　an　IES,　the　electricity　grid　and　combined　heating　and　power　(CHP)　contribute　the　most　to　the　system＇s　resilience.　Overall,　this　study　is　expected　to　provide　quantitative　insights　for　the　seismic-resilient　design　of　IES.