Sunday, October 16 2005 12:45 Hrs (IST) - World Time -

Ahmedabad: Can high intensity geotectonic movements like the devastating earthquake in the Himalayan range which occurred recently in Jammu and Kashmir and Pakistan affect the course of rivers like the Ganges and the Indus?

The possibility cannot be ruled out, according to a senior scientist with Indian Space Research Organisation (ISRO) who has been tracking the course of the Vedic age river Saraswati which, according to him, disappeared over 5,000 years ago due to a major geotectonic activity.

The scientist P S Thakker had recently presented a paper describing the geotectonic effect that led to the disappearance of the river Saraswati at the Madhya Pradesh Council of Science and Technology and also at the Marine Archeology Seminar at Goa early this month.

His major work relates to tracking the palaeo course (ancient course) of Saraswati river and its tributaries using satellite imagery.

He says any major tectonic activity such as earthquake or volcanic eruptions can affect the course of rivers, especially if they occur nearby.

"River Saraswati, which was considered to be the holiest and mightiest river, had totally disappeared precisely because of this reason," he said.

However, it does not mean that every tectonic activity should necessarily affect the course of the rivers, he added.

Thakker said it was the geotectonic activity thousands of years ago which is believed to have caused Manapas to come up in the Himalayas in the Tibet border cutting off the course of river Saraswati at that point.

In Gujarat, the formation of the Gulf of Cambay (Khambat) and Gulf of Kutch is attributed to geotectonic activity.

Thousands of years ago, the sea level in this region was very low but geotectonic activity altered the land mass resulting in the formation of the Gulf in these two regions, he added.

He said during the 2001 earthquake in Gujarat which had its epicentre near Bhuj, a channel appeared in the Great Rann of Kutch which was nearly 100 kms long and 200 mts wide.

The most interesting feature of this channel was that different water samples taken from it showed the age of the water ranging from 12,000 years to 89,000 years old. The age of the water samples were determined by using the scientific method of Radon dating, he added.

Thakker, in his work of tracking the palaeo course of Saraswati, has studied using satellite imageries and described how this river used to come up from Kapalthirth in the Himalayas in the west of Kailash passing through Mansarovar and Raksastal in Tibet, Manapas in Uttaranchal, Rishikesh and Haridwar, Delhi, Jodhpur in Rajasthan and finally the Rann of Kutch in Gujarat where it used to join the Arabian sea.

The interesting part of the satellite imagery is that one can identify the existence of river which has totally dried up. One can also know the course of the river and its tributaries and also whether it has shifted its course. The parts in the satellite imageries where rivers existed appear as dense region having different colourations.