Recurrence of mild tremors in Idukki district in Kerala is causing concern over the safety of the 120-year-old Mullaperiyar dam, located on the borders with Tamil Nadu.

As many as 22 mild tremors and after-vibrations have occurred in parts of Idukki and adjoining Kottayam and Pathanamthitta districts since January this year, officials said.

Two brief spells of quakes measuring 2.02 and 3.04 on the Richter scale gently shook the area including the dam site on Friday last. The officials in charge of the reservoir spotted two minor cracks on it bottom, believed to have been caused by the latest tremor.

Taking a serious note of the development, Kerala Chief Minister Oommen Chandy sent Revenue Minister Thiruvananchur Radhakrishnan with a team of engineers, scientists and disaster management experts to the area to review the situation and suggest urgent steps, if any required, to allay fear of the locals.

But Deccan Chronicle can report today that the state government still has no disaster management plan in place, if the dam bursts - the calamity will affect four districts. Kerala has been arguing that that lives of about 5 million people would be in danger if the structure collapses.

Mullaperiyar dam was built when this part of Kerala was part of the Travancore princely state and Tamil Nadu under the Madras province under the British rule.

The core team of engineers pursuing Kerala's case has argued that Mullaperiyar is one of the few surviving dams in the world made of lime-and-surky mixture.

The dam, a major source of irrigation for the agricultural belt of central Tamil Nadu districts, has also been a subject of hot dispute between the neighbouring states.

Local resistance movements have also been active in Kerala, dominated by small and marginal farmers subsisting by growing crops like pepper and cardamom, pressing for dismantling the existing dam and building a new one.

While Kerala wants to decommission the structure and build a new one, that idea has not found favour with Tamil Nadu. Apart from local resistance groups, political parties on both sides have often taken aggressive postures on the issue.

In 2006, Kerala government passed the Kerala Irrigation and Water Conservation (Amendment) Act 2006, which prohibited the raising of water level beyond 136 ft in the Mulla Periyar Dam as it was placed under the Schedule of 'Endangered Dams'.

The Act was passed after the Supreme Court had held in 2006 that raising the water level of the dam would not be a threat to the safety and security of its structure and permitted raising the water level of the dam from 136 ft to 142 ft.

Tamil Nadu approached the Supreme Court after Kerala government passed the Kerala Irrigation and Water Conservation (Amendment) Act 2006.

With the litigation over the dam's future dragging, the Supreme Court last year appointed an empowered committee headed by former CJI Justice A.S. Aanand to look into the issue and make suggestions for resolving the tussle.

Kerala has consistently maintained that the state has no intention to deny the irrigation rights of Tamil Nadu. Apart from fears over the Mullaperiyar over the tremors, major hydro electric projects of Kerala are located there.

The power board officials, however, have discounted the chances of mild quakes causing damage to projects since they have been built on strong foundations taking into account possibilities of such eventualities.

But scientists have suggested a thorough seismological study of the area in view of the present scenario.

Realising the importance of constant monitoring, the government had a few months back allotted funds for setting up digitised seismographs to gather accurate