A second episode of a moderate quake reported from the neighbourhood in as many days has made people in the State suddenly feel vulnerable to the threat from the earth's underbelly.

An underwater quake of M4.7 (magnitude of 4.7 on the Richter scale) was reported in the normally quiet Lakshadweep Sea off Sri Lanka on Saturday evening.

Panic calls reached media offices, the State disaster management authority and the Met Centre, since this follows the previous day's twin rumble, though of lighter intensity, reported from land in the dam-bound Idukki district.

This, even after a US Geological Survey alert suggested that the epicentre of the quake was located at a ‘safe distance' away from the peninsular tip.

Unlike the Idukki rumbles, the Lakshadweep quake triggered hardly any perceptible ground movement in Kerala.

According to the USGS, the quake occurred at a depth of 10 km at a place 342 km south-southwest of Colombo; 373 km south-southwest of Negombo; and 412 km south-southwest of Kandy, all in Sri Lanka.

The quake was way below the intensity threshold to trigger a tsunami alert, in any case.

The regional office of India Meteorology Centre here and the one of the Centre for Earth Science Studies (CESS) located at Peechi near Thrissur, too, recorded the quake.

Meanwhile, the Indian National Centre for Ocean Information Services (INCOIS) at Hyderabad had revised the magnitude of the underwater quake to M5.2.

A bulletin issued by the Indian Tsunami Early Warning Centre at INCOIS at 4.18 pm on Saturday said there was no threat of a tsunami for India.

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