The 8.7-magnitude quake that hit the coast off Indonesia on Monday evening did not result in massive tidal waves, which might be related to the way that the earth crusts displaced, said Acting Scientific Officer of Hong Kong Observatory Chan Ying Wa Tuesday.

In an interview with Xinhua, Chan speculated that when the earthquake happened, the earth crusts displaced horizontally instead of vertically which could cause large amount of seawater to heave, which in turn, leads to destructive tsunamis.

"It is not likely that a huge tsunami would come again since the fastigium for a severe tsunami to happen was over, which should be within the first one or two hours when the quake happened," explained Chan.

Although there are no signs that the quake will trigger off massive tidal waves, according to information given by the Pacific Tsunami Warning Center, a rise of sea level at 0.2 meter was recorded at Maldives telling that a small tsunami did happen, said Chan.

Chan said the epicenter of Monday's earthquake was very near to the one on Dec. 26 last year. This could be an aftershock of the previous quake disaster.

The Hong Kong Observatory measured the quake at 0:15 (1615 GMT)at 8.7 on the Richter scale, and at 7:15 AM (2315 GMT), an aftershock at 5.7 magnitude was measured.

The epicenter of the quake was initially determined to be near the seas of northern Sumatra, Indonesia (2.1 north latitude, 97.0 east longitude), about 410 kilometers south-southeast of Banda Aceh.

"The Hong Kong Observatory is keeping close contact with the Pacific Tsunami Warning Center, and keeps updating the public with the latest news about the quake although Hong Kong has a very low chance of being affected," Chan said.

Besides staying alert to any changes in the earthquake's situation, the Hong Kong government has also got prepared to provide assistance to citizens who might be there at the disaster area.

But Secretary for Security of Hong Kong Ambrose Lee said Tuesday morning that no requests for assistance have been received so far.

Noting there were no Hong Kong tourist groups in the affected region, Lee said the Hong Kong government will keep a close watch on the incident.

According to Indonesia's Meteorological and Geophysics Office, the severe quake lasted up to three minutes and tsunami warnings were issued.

(Xinhua News Agency March 30, 2005)