<P> Spread roughly north -- south along the east bank of the Hooghly River , Kolkata sits within the lower Ganges Delta of eastern India ; the city 's elevation is 1.5 -- 9 m ( 5 -- 30 ft ) . Much of the city was originally a wetland that was reclaimed over the decades to accommodate a burgeoning population . The remaining undeveloped areas , known as the East Kolkata Wetlands , were designated a `` wetland of international importance '' by the Ramsar Convention ( 1975 ) . As with most of the Indo - Gangetic Plain , the soil and water are predominantly alluvial in origin . Kolkata is located over the `` Bengal basin '' , a pericratonic tertiary basin . Bengal basin comprises three structural units : shelf or platform in the west ; central hinge or shelf / slope break ; and deep basinal part in the east and southeast . Kolkata is located atop the western part of the hinge zone which is about 25 km ( 16 mi ) wide at a depth of about 45,000 m ( 148,000 ft ) below the surface . The shelf and hinge zones have many faults , among them some are active . Total thickness of sediment below Kolkata is nearly 7,500 m ( 24,600 ft ) above the crystalline basement ; of these the top 350 -- 450 m ( 1,150 -- 1,480 ft ) is Quaternary , followed by 4,500 -- 5,500 m ( 14,760 -- 18,040 ft ) of Tertiary sediments , 500 -- 700 m ( 1,640 -- 2,300 ft ) trap wash of Cretaceous trap and 600 -- 800 m ( 1,970 -- 2,620 ft ) Permian - Carboniferous Gondwana rocks . The quaternary sediments consist of clay , silt , and several grades of sand and gravel . These sediments are sandwiched between two clay beds : the lower one at a depth of 250 -- 650 m ( 820 -- 2,130 ft ) ; the upper one 10 -- 40 m ( 30 -- 130 ft ) in thickness . According to the Bureau of Indian Standards , on a scale ranging from I to V in order of increasing susceptibility to earthquakes , the city lies inside seismic zone III . </P>
<P> Spread roughly north -- south along the east bank of the Hooghly River , Kolkata sits within the lower Ganges Delta of eastern India ; the city 's elevation is 1.5 -- 9 m ( 5 -- 30 ft ) . Much of the city was originally a wetland that was reclaimed over the decades to accommodate a burgeoning population . The remaining undeveloped areas , known as the East Kolkata Wetlands , were designated a `` wetland of international importance '' by the Ramsar Convention ( 1975 ) . As with most of the Indo - Gangetic Plain , the soil and water are predominantly alluvial in origin . Kolkata is located over the `` Bengal basin '' , a pericratonic tertiary basin . Bengal basin comprises three structural units : shelf or platform in the west ; central hinge or shelf / slope break ; and deep basinal part in the east and southeast . Kolkata is located atop the western part of the hinge zone which is about 25 km ( 16 mi ) wide at a depth of about 45,000 m ( 148,000 ft ) below the surface . The shelf and hinge zones have many faults , among them some are active . Total thickness of sediment below Kolkata is nearly 7,500 m ( 24,600 ft ) above the crystalline basement ; of these the top 350 -- 450 m ( 1,150 -- 1,480 ft ) is Quaternary , followed by 4,500 -- 5,500 m ( 14,760 -- 18,040 ft ) of Tertiary sediments , 500 -- 700 m ( 1,640 -- 2,300 ft ) trap wash of Cretaceous trap and 600 -- 800 m ( 1,970 -- 2,620 ft ) Permian - Carboniferous Gondwana rocks . The quaternary sediments consist of clay , silt , and several grades of sand and gravel . These sediments are sandwiched between two clay beds : the lower one at a depth of 250 -- 650 m ( 820 -- 2,130 ft ) ; the upper one 10 -- 40 m ( 30 -- 130 ft ) in thickness . According to the Bureau of Indian Standards , on a scale ranging from I to V in order of increasing susceptibility to earthquakes , the city lies inside seismic zone III . </P>
where is calcutta india located on the map
where is calcutta india located on the map
Spread roughly north -- south along the east bank of the Hooghly River , Kolkata sits within the lower Ganges Delta of eastern India
Spread roughly north -- south along the east bank of the Hooghly River , Kolkata sits within the lower Ganges Delta of eastern India