Earthquake is such a phenomenon that the medium inside the earth generates sudden local fractures and emits shock waves, hence causing ground shocks in certain regions. Based on the causes, the earthquake can be divided into tectonic earthquakes, volcanic earthquakes, collapse earthquakes, induced earthquakes and artificial earthquakes etc. Tectonic earthquakes refer to such kind of earthquakes that the rocks fracture and stagger in depths of the earth to transmit the accumulated energy rapidly in ways of seismic waves to all directions, causing vibrations of houses and the ground, such kind of earthquakes occur more often than others, accounting for over 90% of that happening in the world, and having the most powerful destruction.

Strong earthquakes will cause severe personal injuries and property losses. For example, in July 28th of 1976, an earthquake of magnitude 7.8 occurred in Tangshan, China, causing more than 242,000 people dead, over 164,000 wounded. In May 12th of 2008, an 8-magnitude earthquake occur in Wenchuan, Sichuan Province, causing 69,227 people dead, 374,643 wounded and 17,923 missing.

Although Shanghai has never suffered earthquakes over magnitude 5 so far according to historical records, this does not mean the earthquakes over magnitude 5 will not happen in Shanghai, but that intense earthquakes might occur in surrounding regions of Shanghai to have an impact on Shanghai is potential. For Shanghai has dense population and concentrated buildings, which will enlarge the hazards of earthquakes. Therefore, we must emphasize the public protections when earthquakes occur.

The public protection measures mainly contain: First, transfer the public. If we can predict the occurrence of earthquakes, we can organize the residents to retreat from buildings before the occurrence earthquakes, and transfer them to squares, playgrounds, parks, green fields and other open areas as well as rural areas for prevention of earthquake hazards; if we can not predict the earthquakes, we will organize the residents to retreat from buildings after the occurrence of earthquakes, and transfer them to safer areas for sheltering temporarily. Second, organize mobile personnel in public places to carry out emergency aids. When earthquakes occur, organize mobile personnel in densely-populated public places such as stores, hotels, cinemas, gymnasiums, bus stations, ports, airports and subway stations etc. to take emergency aid measures and withdraw in order after the earthquakes. Third, carry out self aids and mutual aids. After occurrence of the earthquakes, organize promptly communities and civil defense units of establishments, volunteers and the public to carry out self aids and mutual aids before the arrival of professional recuing teams and other rescuing forces. Four, arrange temporary shelters. After organizing the residents to withdraw from buildings and transferring them to safer areas, do the temporary sheltering work well, including establishing temporary Party and Government organizations, making the public assured, providing necessities such as foods, drinking water, clothes and quits, tents etc. promptly, providing medical services, and launching health epidemic preventions and other works. Five, implement preventions of secondary disasters. After the occurrence of earthquakes, such secondary disasters like fire, hazardous chemical leakage, dike breaches of reservoirs, rivers and lakes etc. may happen, therefore, we must actively organize the public to carry out preventions against secondary disasters of earthquakes.