"Elastic city" refers to the ability of a city or urban system to solve and resist external shocks and keep its main features and functions unaffected. In other words, when a disaster occurs, a city with resilience can withstand the impact, respond and recover quickly, maintain the normal operation of urban functions, and better cope with future disaster risks through adaptation.

The construction of disaster-resistant cities will establish a set of disaster-resistant evaluation index system suitable for urban characteristics according to the characteristics of cities, disaster prevention needs and the types and sizes of disaster risks. This index system is usually established at different levels and in different fields. A city may establish hundreds or even more indicators to evaluate the level of disaster resistance by combining qualitative and quantitative methods.

From a macro point of view, cities with disaster resistance have the following main characteristics:

First, when a disaster occurs, the loss of life and property is controllable, that is, the casualties and property losses are small;

Second, the main functions of the city are not interrupted or can be quickly restored;

Third, the disaster preparedness and relief system is perfect, which can be started quickly and there is no chain reaction of disasters, that is, there are few secondary disasters;

Fourth, the time and degree of post-disaster recovery can meet the needs of society, that is, recovery is fast.

The concept of disaster-resistant city has actually brought new changes to the concept of urban disaster response. The original method to deal with natural disasters is "hard resistance". For example, the loss of life and property caused by earthquake mainly comes from the collapse of houses caused by strong earthquake vibration, so the traditional practice mainly relies on thickening, thickening wall columns or increasing the number of steel bars to build strong houses to resist this impact.

But it turns out that when the earthquake is relatively large and exceeds the local seismic fortification threshold, the house can't bear it. Therefore, the method of "hard resistance" has been difficult to cope with this extreme disaster, so it is extremely necessary to adopt the method of "combining rigidity with flexibility", that is, to apply the concept of "toughness" to better do the seismic fortification work of construction projects.