A fault is a fracture or zone of fracture between two blocks of rock. Faults allow the blocks to move relative to each other. This movement may occur rapidly, in the form of an earthquake – or may occur slowly, in the form of creep. Faults may range in length from a few millimetres to thousands of kilometers. Most faults produce repeated displacements over geologic time.
During an earthquake, the rock on one side of the fault suddenly slips with respect to the other. The fault surface can be horizontal or vertical or some arbitrary angle in between.
Some major faults in India:
The Churachandpur Mao Fault is named after two places in Manipur and runs north-south into Myanmar along the border of Champhai. Mizoram is caught between two geological faults. These are the Churachandpur Mao Fault and the Mat Fault, which runs northwest-southeast across Mizoram, beneath river Mat near Serchhip and thus experiences frequent tremors.
Malda Fault: It is the fracture in the rock observed in the Malda district of West Bengal. The fault runs several layers deep below the earth’s surface and is formed during the upliftment of the Himalayas. It separates the Meghalayan Plateau from the Chota Nagpur Plateau.
Bhima fault: found in the southern part of the river Bhima basin in Maharashtra. The Southern part of Bhima basin was displaced transversely towards west. The net slip of this fault on the northern part is about 35 km. Second-order shears are numerous in the area. Gravity and thrust faults are also observed in the region. Folds of plunging, non-plunging and superposed types are identified. The basin seems to be tilted towards the north at 5° or, possibly, the central part of the basin is sunken.
The Allah Bund Fault scarp is an elongated steeply dipping south-facing scarp bordered on the south by the salt-encrusted surface of Rann of Kutch. On June 16, 1819, one of the biggest earthquakes hit the Indian sub-continent. The tremblor, which created a ridge 90 km long, 16km wide and 3-4 m high in Greater Rann – all in less than a minute – continues to intrigue geologists and earth scientists event today.
Ishu
Some major faults in India: