The possibility of Hong Kong being hit by a major earthquake is slim, Hong Kong Observatory Director Lam Chiu-ying says.

Speaking on a radio talk show today, Mr Lam said small-scale tremors can usually be felt in Hong Kong once or twice a year.

He said an earthquake measuring 7 on the Richter scale will happen once every 300 to 400 years, adding the strongest earthquake was recorded in 1918 which caused only minor damage and cracks to buildings.

He said an emergency response system and a comprehensive contingency plan are in place to deal with natural disasters, including earthquakes.

Mr Lam said although the local buildings have not been designed to withstand tremors, they can still bear the effect of an earthquake as they are constructed to resist strong winds.

He said the observatory is unable to predict when earthquakes would happen but the department would enhance the public's knowledge of earthquakes through web information and lectures.

Rainstorm response effective

In response to criticism suggesting the department was late in issuing the red rainstorm warning on Thursday morning, Mr Lam said it was difficult to predict rainstorm as it will come up suddenly and affect a relatively small area.

He said the rainstorm warning system is designed to serve as an alert system for the public, adding students should stay in schools after they have arrived there and parents should only let their children leave when it is safe to do so.