Problems of Engineering Seismology: article

Аnnotation: The Ganges-Brahmaputra Delta (GBD), the world's largest delta, has been built from sediments eroded from the Himalayan collision. These sediments have prograded the continental margin of the Indian subcontinent by ca. 400 km, forming a huge sediment pile that is entering the Burma Arc subduction zone. Critical facilities are located in the central part of the GBD. Although the site is more than 300 km away from Indo-Burma subduction zone to the east and from Himalayan collision zone to the north, these global-scale structures govern to a great extent the seismicity and seismic hazard in the central part of the GBD. Scarps were found and studied on the site of the critical facility location. They were cut by trenches. In the trench walls were found inclined layers with minor vertical offset, which could be interpreted as evidence on palaeoearthquake. But farther digging of the trench demonstrated that the inclined layers are underplayed by horizontal undisturbed layers of sediments. The whole situation is interpreted are interpreted as an evidence of erosion and sedimentation processes caused by fluctuations of Ganges River flow-course, which is observed in all trenches.