Legislative Council Question 5 : "Seismic resisting capability of buildings" by the Dr Hon Raymond Ho and a reply by the Secretary for Housing, Planning and Lands, Mr Michael Suen, in the Legislative Council
Following is a question by the Dr Hon Raymond Ho and a reply by the Secretary for Housing, Planning and Lands, Mr Michael Suen, in the Legislative Council today (February 7):
It has been reported that in recent years, when intense earthquakes took place in neighbouring places, many members of the public in Hong Kong could feel the buildings where they were swaying, and some of them even fled the buildings in a panic for safety. Given that the existing legislation in Hong Kong does not require buildings to be able to withstand earthquakes, will the Government inform this Council whether it will consider enacting legislation to impose such a requirement; if it will, as enactment of legislation takes time, whether the authorities will accord priority to enhancing the ability of existing disaster emergency relief facilities (buildings such as fire stations, hospitals and police stations, etc) to withstand earthquakes, so as to ensure that such facilities can still operate in the event of earthquakes?
Intense earthquakes in the world mostly occur along crustal plate boundaries. Hong Kong lies within the Eurasian Plate but not along the boundary. The well-known Circum-Pacific Seismic Belt is located along the boundaries of the Eurasian Plate and the Pacific Plate, stretching through neighbouring regions of Japan, Taiwan and the Philippines where earthquakes frequently occur. As Hong Kong is not situated along this active seismic belt, the possibility of having serious earthquakes in the territory is relatively low.
Since 1905 when the Observatory started recording locally felt earthquakes in the territory, Hong Kong has recorded 162 tremors of different magnitudes. Such earthquakes have not caused any casualties. The strongest tremor ever recorded was of Intensity VI to VII on the Modified Mercalli Scale (MMS). This locally felt earthquake occurred more than 300 km away from Hong Kong in the neighbourhood of Shantou in 1918, and inflicted minor damage on walls of a few buildings constructed under the prevailing building standards at that time. This has been the only earthquake that has caused damage in Hong Kong since 1905.
The Buildings Department (BD) has commissioned a consultancy study on issues concerning seismic effects. The major purpose is to assess the earthquake risks in Hong Kong and the effects of earthquakes on local buildings. The study is still on-going. We hope to complete the study as soon as possible.
The extant Buildings Ordinance does not require private buildings in Hong Kong to possess seismic-resistant designs. However, the Ordinance stipulates that buildings in Hong Kong should be able to withstand wind gusts of 250 km per hour, and hence such buildings posses a very high load-resisting capacity. In the event of an earthquake of MMS Intensity VII, buildings constructed according to the current standards should still be safe and suffer no serious damage.
The above has also been confirmed by the preliminary findings of the consultancy study commissioned by the BD, that is, most of the buildings in Hong Kong are basically safe in the event of an earthquake that may take place in the territory. Upon completion of the study, we will examine the results in detail and consider whether there is a need to introduce legislative amendments to enhance the capability of buildings to resist seismic effects.
Regarding the seismic resisting capability of buildings such as fire stations, hospitals and police stations, these buildings have been designed to be wind resistant since the 1930s. The standard of wind resistance for these buildings has also been regularly revised and upgraded to meet changing needs. As such, these buildings are basically safe and will suffer no serious damage in the event of an earthquake that may occur in Hong Kong.
In case of the occurrence of any serious incidents in Hong Kong, the Security Bureau will, according to the circumstances, promptly initiate the established contingency measures. It will also coordinate the command and control centres of the emergency services and supporting departments to carry out rescue, recovery and restoration work.
The bureaux and departments concerned will consider whether there is a need to enhance the seismic resisting capability of buildings such as fire stations, hospitals and police stations upon completion of the BD's consultancy study.
Ends/Wednesday, February 7, 2007
Issued at HKT 15:09