The River Man

Geophysicist Dr Hamza has a subterranean river in the Amazon basin named after him,in honour of his research.

Written by Shaju Philip | New Delhi | Published: September 14, 2012 5:06:17 am

Geophysicist Dr Hamza has a subterranean river in the Amazon basin named after him,in honour of his research.

It happened three years ago,almost by accident. A student,Elizabeth Tavares Pimentel,couldn’t interpret the data on unusual temperatures in the Amazon river basin. Her guide,professor Dr Valiya Mannathal Hamza,had been studying sub-surface thermal fields in the Amazon basin for the last 40 years. A professor at the department of geophysics at Brazil’s National Observatory,Hamza’s analysis led them to an underground “river’’ beneath the Amazon river. It has now been named after him in his honour.

During a recent visit to his home town Kozhikode in Kerala,Hamza,71,talked of his “find”. Pimentel,had gathered geothermal data from deep boreholes and oil wells abandoned by oil firm Petrobras along the basin of the Amazon river. Hamza was aware that the oil firm had data on temperatures from the 1970s and the 1980s. “However,I got the opportunity to unravel it only after Pimentel sought my help,’’ he says. Along with four other students of geophysics,they examined 240 oil wells abandoned by the firm. The oil wells were within the forest. They had to stay in a small town,close to the forest,during their research,which often extended into an entire month. The temperature of the wells,whose depth ranged from 1,000 to 4,000 metres,was measured using thermometres,which had memory cards fixed to them. The thermometres were lowered into the wells,using lightweight cables and special sensors. The memory card data would then be fed into a computer.

The study found that in the Amazon region,the rock formations are cold,which means that the water penetrates from the surface to underground. The upper part of the geological formations is characterised by a downward flow of ground water. On the other hand,the lower part of the geological formation in the river shows water flowing laterally,from west to east. The word “river” here,is used in a generic sense. This particular river is not a “normal” river,it has no fish and biological activity. Hamza explains that water movement takes place in many different ways. There are atmospheric rivers,also known as flying rivers. For instance,a landslide is an atmospheric river. Then,there are surface rivers. Some surface rivers have rivers underneath,called subterranean rivers,which are new to the scientific world.

A subterranean river,such as the Hamza,flows deep from 1,000 m to 4,000 m,below the surface. “In surface rivers,water flows at one meter per second,whereas in underground rivers,it is a few hundred meters in a year. It is almost the same speed at which a river flows under glacier formations.’’ The Amazon river is 6,110 km long,and its underneath water body meanders along 6,000 km. It is 100 km wide,while the river Hamza is 400 km.

The study was funded by the science and technology department of the Brazil government,at an expense of 1,00,000 US dollars. Mapping the tributaries will be more expensive.

In August last year,the Journal of South American Earth Sciences published their discovery. The study was also presented at the Brazilian Geophysical Society’s meeting that was attended by scientists from across the world. “The science community was initially sceptical about the finding. There is a group of geologists who think it is not proper to name the finding a “river”. It will take time before geologists and hydrologists understand the importance of this underground flow,” he says.

He believes that rivers in India that flow through plains could be permeable,which makes it possible for the Ganga,Yamuna,Indus,Godavari and Brahmaputra to have underneath water flows.

Beneath the Surface

Dr Valiya Mannathal Hamza left Kerala in 1966 after his graduation

With a post-graduation degree from the National Geophysical Research Institute,Hyderabad,he left for Canada to complete his doctoral studies

In 1974,he went to Brazil for a six-month stint in teaching

He settled in Brazil and married Noor Miadaira,now a retired Brazilian teacher of Japanese descent

He has authored around 100 articles on geophysics

Hamza is well-versed in Portuguese

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