Sustainability is defined as the capability of the system to maintain and indure itself while Reslience is thr property of the system to bounce back to its origina state. Please further read.
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Resilience is a measure of the degree to which a system is capable of self-organization, or in the case of disaster management, the effectiveness (in time and logistics) to which a city recovers from a disaster.
Sustainability in disaster management is: the capacity to achieve continued economic and social development without detriment to the environment and natural resources through balancing biophysical, economic, and political/cultural/social drivers (Blockley & Heslop, 2001).
You can can find a comprehensive review of these terms including robustness, flexibility and changeability in: https://ascelibrary.org/doi/abs/10.1061/%28ASCE%29IS.1943-555X.0000467
Resilience and Sustainability should be seen hand in hand in the field of Disaster Management. The former should consider a scenario exposed to all kind of disasters in a particular geo-environ while developing infrastructure. Sustainability identifies socio-economic and environmental factors and benefits of a geo-environ while planning Therefore, both should be considered in an apposite manner in the field of Disaster Mgt.
In short, for easy understanding the resilience is kind of guard wall from the particular disaster event by minimizing risk through enhancing pre and post disaster capacity building and adaptive measures, where the sustainability is the overall development by achieving the resiliency in disaster management.