Mild tremors were felt on Saturday in parts of Idukki district, where the 116-year-old Mullaperiyar Dam over which Kerala and Tamil Nadu are locked in a row with conflicting claims about its safety is located.
The tremors were of low intensity measuring 2.7 on the Richter scale and were followed by two more brief spells, according to Kerala State Electricity Board officials.
However, no damage to property or injury to people was reported, officials said.
The area had recorded as many as 21 mild quakes since January this year with Kerala citing it as a threat to the dam and insisting on building a new reservoir to replace the existing one which it contends is weak.
However, holding a contradictory view, Tamil Nadu has opposed construction of a new dam, asserting that the present reservoir "is as safe and good as new" and accused Kerala of whipping up fear psychosis.