The Hong Kong Observatory recorded a severe earthquake of magnitude 7.2 near the Luzon Strait at about 8:26pm on Tuesday. It has disrupted telecommunications in Hong Kong and the region as several operators say their undersea cables were damaged.

Officials in Taiwan say two people were killed in a building collapse, and at least 40 were injured.

The quake's epicentre was estimated to be about 97 kilometres south-southeast of  Kaohsiung, over the Luzon Strait.

A number of local residents reported feeling this tremor, which lasted only a few seconds. 

Urgent cable repairs underway

The Office of the Telecommunications Authority, or OFTA, confirmed that external telecommunications services in Hong Kong - including Internet access to overseas websites, IDD calls and roaming calls - had been affected, as a number of submarine cables had been damaged in the earthquake.

Operators' reports to OFTA confirm telecoms users have been facing severe congestion in a number of external services. The congestion is expected to continue for a few days. Meanwhile, operators are taking measures to maximise their existing facilities' throughput and using alternative routings. 

The submarine cables' operators have arranged urgent repairs, although some are expected to take at least five days. Users are urged to minimise non-essential Internet access to overseas websites and not to repeat making non-urgent overseas calls after failed call attempts.

Quake posed no danger to HK

In response to enquiries concerning precautions to take during earthquakes, the Hong Kong Observatory's Senior Scientific Officer Dr WT Wong noted the chance of an intense tremor occurring in Hong Kong was low.

He gave last night's tremor an intensity rating of three to four on the Modified Mercalli Scale of 12, based on reports from people who say they felt it.

A tremor with an intensity of seven occurs here about once every 350 to 400 years. At this intensity, the scale suggests, it is difficult to stand, is noticed by car drivers, hanging objects quiver; furniture is broken, there may be damage to bricks, waves will appear on ponds, large bells will ring and concrete irrigation ditches are damaged.

Locally felt tremors occur on average twice a year, and there have been 53 in Hong Kong since 1979. The one with the highest intensity was five to six on the scale, from an earthquake that occurred in the southern part of the Taiwan Strait on September 16, 1994.

Another, with an intensity of four to five, was from an earthquake off the east coast of Lantau Island on May 11, 1995. 

None of the other tremors since 1979 has been above four.

Safety tips - just in case

Click here for some basic safety tips in the event of an earthquake.

According to reports, the tremor's magnitude - a measure of the total energy released - was estimated to be 7.2 on the Richter scale. An increase of one step in the magnitude corresponds to a 32-fold increase in the energy released.