An aerial view of highrises along Puri beach. Picture by Ashwinee Pati

Puri, Feb. 21: The beach town is facing a threat with highrise buildings along its seashore showing signs of tilt, a possible fallout of tectonic movements, which is yet to be studied in detail. An expert team of the Geological Survey of India (GSI) would visit Puri to study the situation.

Residents of the holy town have confirmed that the cracks began to be noticed after 2004 in the wake of the earthquake and tsunami in Sumatra, which had a far-reaching impact. Some of the residents have undertaken repairs on their own.

Geoscientist and former deputy director general of the GSI P.N. Nayak, who has been studying the phenomenon and is expected to guide the expert team, said the tilted buildings in Puri could be a precursor to an impending disaster. Nayak attributed it to the impact of the 2004 tsunami or the rise of the earth’s mantle material through the oceanic ridges between Brahmagiri and Sakhigopal near Puri. The ridge extends over 1,600km, connecting Sri Lanka.

“The tilted buildings are either caused by pressure transferred from the oceanic crust after 2004 Sumatra quake or the upwelling (an oceanographic phenomenon that entails rising of cold, usually nutrient-rich waters from the ocean depths to the warmer, sunlit zone at the surface) of mantle material through the ridge that may result in further tilting of the buildings and disastrous crustal movements,” said Nayak.

The road running parallel to the shore in Puri had been breached by a massive surge of the sea in 2007, a phenomenon generally attributed to global warming but which, it now appears, could also have been connected to the oceanic crust movements in the wake of the Sumatra tragedy. The road has developed not only cracks, but also elevations and depressions of more than one metre at certain points.

While the already visible tilt in the buildings make them disaster prone, Nayak felt that in the event of an earthquake, the destruction could be minimised if a prediction programme was implemented. “The time and site of quakes can be predicted in advance up to a minimum of 11 days. However, it is necessary to investigate whether tilts change with time and if strains have been accumulating on the tectons. A protective wall must be constructed at the sensitive sites to prevent marine transgression,” he said.

On the other hand, the tilt in the buildings is hardly noticed if viewed from the beach road, extending from Banki Muhan in the east to Baliapanda on the western side. One has to trudge through the golden sands and look at the buildings from the southwestern side, or drive up to the Baliapanda side at least to the point where the road bends for the tilt to be visible.

All the buildings, bordering Beach Road or along the narrow lanes running perpendicular to the road, are seen uniformly tilted. This vertical slant is nearly three to four degrees towards the northern side.

“Buildings, constructed in the early 20th century and which stood erect till 2005, have been tilted. So, the foundation defects and other problems related to construction are ruled out. The tilt is the result of either pressure transformed from the oceanic crust after the 2004 Sumatra quake (tsunami) or upwelling of mantle material through the ridge. This might lead to further tilting of the buildings and disastrous crustal movements,” said Nayak.

Local resident Sarat Achari, 56, said he had noticed some cracks on the houses in his area. He said: “It is frightening to think that the cracks are the lingering effect of a calamity that took place eight years ago.”

Moreover, the uppermost floors of the multi-storey structures, at present, are not exactly above the ground floors. “Any progressive increase of the tilt may develop cracks at the weak points of the building and it would collapse northwards like a pack of cards,” Nayak said.

Local fisherman P.V. Narasimha Rao has noticed the tilt from the sea. “There have been some changes over the past six or seven years. We can clearly see the tilt when we are out in the sea,” Rao said.

Nayak suggests that the terrace of a few buildings, especially those that are close to the beach, should be examined to determine the azimuth (angle used to define the apparent position of an object in the sky, relative to a specific observation point and direction of maximum tilt).

“Preparation of a tentative contour map of the ground surface is also necessary now. It is suspected that the nature of the lithosphere and crustal block underlying the zone of tilted buildings has been changed after 2004-05,” he said.

Moreover, sudden rise in the sea water-level and coastal erosion have become a cause of concern for the town residents. President of the Puri Hotel Owners’ Association Ramakrushna Das Mohapatra said though he had failed to notice any tilt in the highrises, the sea water-level had indeed gone up.

Puri town planning officer R.M. Mishra, who is also secretary of the Puri Konark Development Authority, admitted a water-level rise and ingress of the sea at a number of points. “Keeping this in mind, we have been following strict rules based on nine parameters while approving building plans in this zone since 2004,” he said, adding that he was not aware of the tectonic developments pointed out by the geologists.

“These are things for geoscientists to study. It needs proper research before they arrive at a conclusion. After the GSI undertakes a study in this regard, we would get to know the exact reasons. At this point, I have nothing to comment as I don’t have the expertise,” Mishra said.

However, Nayak said rise of water-level could result from global warming or subsidence of crustal blocks. “Whereas rise of water-level because of global warming has to be uniform globally, subsidence of Puri coast should be affected by local geographical conditions. These two contesting causes can be discriminated through repetitive measurements of permanent benchmarks in the quieter creeks close to the sea employing accurate geodetic GPS methods,” he said.

The phenomenon appears to have coincided with malfunctioning of the town’s sewer system, which indicates disturbances in the earth’s crust underlying Puri.

“It is implied that the crustal or lithosphere block underlying Puri has been disturbed and the ground surface does not slope down towards the sea. The change in the direction of the slope might have resulted in malfunctioning of the sewer system,” said Nayak. The Odisha Water Supply and Sewerage Board has invited expression of interest for the preparation of a detailed project report, involving topographical and marine survey for the establishment of new sewage treatment plant and off-shore sea discharge.

Member secretary of the board Lalit Mohanty refrained from commenting on the issue. “I am new to this organisation and not aware of the development,” he said.