The quake’s epicenter was in China but almost all the damage and death toll occurred in the valley of the Brahmaputra River.
The Assam earthquake of August 15, 1950, magnitude 8.6, was centered at Rima in China, but it was the Brahmaputra valley in Assam that the most extensive damage was experienced. Accordingly, it was named the Assam earthquake. Two thousand homes, temples and mosques were destroyed there and over 1,500 people killed. Many rock falls and destruction of forests were reported in the Mishmi hills north of Assam.
As a result, many of the tributaries of the Brahmaputra were blocked. When some of these opened after a week they created a wall of water, thirty feet high, that destroyed several villages. This earthquake was even more powerful than the Assam earthquake of 1897 but, despite its significance for Assam, it was not an Indian earthquake.
The great Assam earthquake of June 12, 1897, magnitude 8.3, is the largest known Indian intraplate earthquake of the last two centuries. It raised the northern edge of the Shillong Plateau by more than thirty feet, resulting in the destruction of structures over much of the plateau and surrounding areas, and causing widespread liquefaction and flooding in the valley of the Brahmaputra River.
Due to the powerful shaking that this 1950 earthquake caused, the rivers brought down sand, mud, trees, and all kinds of debris. Pilots flying over the area reported great changes in topography. Huge landslides had occurred and, as they were photographed and compared with existing images, it was seen that the overall topography had changed, to the extent that the view from the air was no longer the same as it had been before 1950.
The only available on-the-spot account of earth movements came from a botanical explorer who was at Rima. However, he had little opportunity for observing more than the violent shaking and the rise in level of the streams because his attention was devoted to how he could escape from the area and get back to India. Aftershocks from the 1950 earthquake were numerous. Many of them were more than magnitude 6 and well enough recorded at distant stations for locating the epicenter.
From such data, the Indian seismological service established an enormous geographical spread for the impact of this earthquake, from about ninety degrees to ninety-seven degrees east longitude, with the epicenter near the eastern margin. One of the aftershocks, a few days later, was felt more extensively in Assam than the main shock, leading certain journalists to the conclusion that the aftershock was bigger than the main one and must therefore be the greatest earthquake of all time!
Assam, from the beginnings of British occupation of India, has always been a fertile agricultural area. It lies in the valley and flood plain of the huge Brahmaputra River and is thus an enormous relatively flat region, facilitating intensive settlement. It receives the highest amounts of rainfall of any part of India and this factor, combined with its warm climate, a function of latitude, has attracted more and more people as infrastructures of roads and railways made it accessible.
Gauhati is a large city near the Brahmaputra River. Over the past few years it has had to face the challenge of invading elephants. There are about 5,000 of these huge animals in the Assam Region and the encroachment on their natural habitat by more and more farmers, involving removal of forest, coupled with the destruction caused by natural disasters, forced the elephants to raid human areas for food for the first time. In the year 2006 as many as fourteen people were killed by these elephants when they invaded Gauhati.