The Assam earthquake of 1897 occurred on June 12, 1897 in Assam, British Raj, and had an estimated magnitude of 8.1Mw.
Thought to have happened 20 miles (32 km) underground, it left 150,000 square miles (390,000 km2) of masonry buildings in ruins and was felt over 250,000 square miles (650,000 km2) from Burma to New Delhi. Numerous buildings in the neighboring country of Bhutan were heavily damaged. There were very many aftershocks.
Considering the size of the earthquake, the mortality rate was not that high, with about 1500 casualties, but property damage was very heavy.
The earthquake occurred on the SSW-dipping reverse Oldham fault that forms the northern edge of the Shillong Plateau within the Indian Plate. There was a minimum displacement on the main fault of 11 m, although up to 16 m has been calculated, one of the greatest for any measured earthquake. The calculated area of slip extended 110 km along strike and from 9 to 45 km below the surface, indicating that the entire thickness of the crust was involved.