Two tremors of mild intensity were reported in Idukki district on Wednesday evening.
An official of the Kerala State Electricity Board's research wing said a tremor of magnitude 1.1 on the Richter Scale was reported at 6.04 p.m., followed by another tremor of 0.7 intensity at 6.06 p.m. No damage was reported.
The tremors were felt in the Kulamavu and Upputhara areas.
The official said the epicentre of the tremors would be known later.
A tremor of magnitude 2.3 on the Richter Scale was recorded in the district on March 10. Another tremor of magnitude 2.1 on the Richter Scale was reported on March 4.
The epicentre of the two tremors was Venjoormedu, near Kannampady, inside the Idukki Wildlife Sanctuary, which is close to the Idukki reservoir.
The increasing number of tremors have heightened the anxiety of the people, especially those living downstream of the Mullaperiyar dam. Venjoormedu lies seven kilometre from Idukki dam and 33 kilometres from the Mullaperiyar dam.