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Epeirogenic movements of regional extent have been manifest and recorded in several parts of India from Late Proterozoic to present times through the Tertiary and Recent. The main features of these movements, especially Recent vertical movements, in typical areas in the platform and coastal areas of peninsular India are described and the salient results of the study, qualitative and quantitative, of these zones are outlined. Quantitative measurements of Recent vertical movements have been made largely by geodetic methods and precision levelling in the plateau areas as also in the mobile, orogen zones of the Himalayan and sub-Himalayan tracts and by sea-level measurements through an extensive network of coastal automatic tide-gauge stations. The annual variations of sea level have been studied for several Indian ports. The land uplift or subsidence in relation to mean sea level over the Indian coast has also been studied. The application of geophysical techniques in the identification and delineation of regions of epeirogenic movements has been discussed and illustrated by the results in two type areas, viz., the coastal sedimentary belt of Madras and the vast Deccan Trap territory in western India. In the latter area, blanketed by extensive basaltic lavas over a vast region, the gravity data have brought out a number of major zones of subsidence and uplift which have been corroborated by the results of refraction seismic soundings. One of these major zones of subsidence is in the Koyna region which witnessed a major disastrous earthquake a few years ago. The results of deep seismic sounding along a traverse across the southern part of the Indian peninsula now in progress have also been briefly mentioned. Five important areas have been selected for quantitative measurements of current epeirogenic movements, namely the Shillong Plateau in northeast India, the Chhotanagpur Plateau and Singhbhum region in Bihar, the Aravalli region of Rajasthan, the Narmada Sone Rift in central India and the Deccan Trap territory including the Koyna earthquake zone.

Recent crustal movements have been observed and studied in several parts of India including the Himalayan and sub-Himalayan regions, the Precambrian shield of peninsular India and also the coastal tracts. The results of studies of Holocene deformation and crustal movements in two type areas are presented, one in the extreme southeastern part of the peninsula and the other in northeastern India. The Precambrian shield in the extreme southeastern part is characterised by a major NE—SW trending fault zone in the Tirupattur—Mattur areas of Tamil Nadu with some major extended faults, one of which apparently cuts through the entire crust and Moho as indicated by gravity data and which is associated with occurrences of alkaline and basic intrusions and carbonatite complex. Evidence of Recent crustal movements in this zone is afforded by geomorphic features and recent and current seismicity of a mild nature which is apparently to be attributed to slow movements along the fault plane. The Shillong plateau in northeastern India occurs as block-uplifted horst, comprising for the most part Archaean crystalline rocks with plateau basalts and Cretaceous and Tertiary sediments occurring on its southern margin. The plateau is bounded by major faults and is located in a zone of high seismicity lying astride and parallel to the eastern Himalayas intervened by the alluvium of the Brahmaputra Valley. Geomorphic features such as raised terraces, straight-edged scarps, etc., provide evidence for Recent crustal movements with dominant vertical movements along the fault planes which have continued through Tertiary and Recent times. Repeated precision levelling measurements conducted by the Survey of India indicate a rate of uplift of 4–5 cm per 100 years during the period 1910–1975. The gravity data pertaining to this region are also discussed in relation to the crustal movements.

Peninsular India is characterized by some major plateau regions. These include the Deccan and Karnataka plateaus of the southern peninsular shield which together occupy an area of more than 400,000 km2 and the smaller Chotanagpur and Shillong plateaus in eastern and northeastern India, respectively. Major parts of the Deccan plateau are blanketed by basaltic lavas of the Deccan trap. The Bouguer gravity map of the region presents a number of gravity “highs” and “lows” suggestive of marked uplift and subsidence involving the crust and the seismic soundings indicate trap thickness varying from about 100 m in the eastern and southern margins of the trap territory to more than 1000 m in the western parts of Maharashtra. A major north-south fault zone has been indicated within the traps along the Bombay coast to the west of the Koyna earthquake-affected area. Marginal north-south as well as east-west faults have also been delineated by gravity and seismic surveys in the off-shore areas to the west of the Bombay coast, south of the Cambay graben and to the south of the Kathiawar peninsula. The prominent WSW-ENE trending Narmada-Son lineament to the north of the Deccan plateau comprises the Narmada-Son rift, which is characterized by basic alkaline rocks and carbonatite occurrences in its western extremity and kimberlite pipes over its eastern parts, which are of great significance in the study of plateau uplift in this region. The gravity data clearly bring out the fault system of this rift which is divided into segments. The Karnataka plateau contiguous to the Deccan plateau to its south consists mainly of Precambrian gneisses, granites and charnockites with some major plutonic masses, apparently connected to the deep-seated batholiths which are reflected in the Bouguer gravity map as strong negative anomalies. This plateau region is characterized by distinctive geomorphic features and mild seismicity. The Chotanagpur plateau also shows distinctive geomorphic features, including some prominent scarps with steep gradients and water falls. The Shillong plateau in northeast India occurs as an uplifted horst block in a zone of high seismicity astride the Himalayan range. Repeated geodetic levelling conducted during the past 70 years across this plateau indicated a total uplift of 2.5 cm during this period. The whole of peninsular India is characterized by particularly strong negative gravity anomalies, the cause of which clearly appears to be within the mantle. The plateau uplifts of peninsular India are apparently releated to thermal processes within the mantle.

The peninsular shield of India is characterized by a number of intra-cratonic sedimentary basins of which the Cuddapah and Vindhyan Basins are conspicuous. The crescent-shaped Cuddapah Basin (~1400 m.y.) covering roughly 35,000 square kilometers in the southern peninsula and enclosing the Cuddapah formations (Precambrian) includes shallow marine shales, limestones, sandstones and quartzites. These sediments are overlain by the younger Kurnool formations of Vindhyan (Upper Precambrian) age in the western and northern marginal portions of the basin and are intruded by basaltic sils and dykes. The eastern margin of the basin is characterized by an overthrust with steeply folded beds, while in the remaining parts, the formations show a gentle eastward dip. Evidence for Recent epeirogenic movements is provided by geomorphic features and current seismicity. The Great Vindhyan Basin of north-central India covering more than 100,000 square kilometers encloses Vindhyan sediments including some marine shales and limestones in the lower parts and shallow-water deposits of red sandstones and shales in the upper parts. The beds are generally horizontal, but are strongly disturbed along the southern margin. There are intrusions of basaltic dykes and kimberlite pipes. The Gondwana basins (Upper Carboniferous to Jurassic) are relatively smaller cratonic units in Archaean faulted troughs. Gravity and magnetic investigations, both regional and detailed, supplemented by deep seismic sounding profiles in the Cuddapah Basin have brought out the deep structural features of the basin, including the Moho, indicating a total thickness of generally 5–8 km with a maximum thickness of sediments of nearly 12 km in the eastern part. The beds show both a layered structure in the horizontal and block structure in the vertical, disturbed by a low-angle thrust fault on the eastern margin. In the Vindhyan Basin, the gravity and magnetic data indicate about 5000 m of sediments in the central portions, with major, roughly faults over the western and southern margins. The deep structural features of these intra-cratonic basins, as indicated by the geophysical results, are discussed in relation to the geological theories proposed for their genesis and development.

The peninsular shield of India in the interior of the Indian Plate is characterized by intra-plate earthquakes. The major earthquakes in the peninsula are associated with prominent fault zones in the margins of the peninsular shield, especially along the Bombay—Ratnagiri coast, the western parts of the Narmada Rift zone and the southeastern parts of the Precambrian shield. Mild seismicity is also observed in several parts in the interior portions of the shield. Prominent recent crustal movements have been observed in the peninsular shield as evidenced by surface geologic and geomorphic features as well as prominent features in the lineament maps, including aeromagnetic lineaments. While the major intra-plate earthquakes are associated with tectonic zones characterized by deep crustal faults, the mild seismicity in the interior of the shield is associated with epeirogenic movements involving the movement of crustal blocks. The regional gravity and magnetic maps of the Deccan-trap region of the shield indicate prominent zones of uplift and subsidence involving the crust. The movements and dislocation with time in the deeper parts of the crust in the major zones of subsidence, as typified by the Koyna earthquake region which is bounded by a major fault zone on its west, obviously also involve displacements in the superincumbent mass of the Deccan trap. This latter being of much higher density and magnetic susceptibility, causes appreciable changes in the observed gravity and magnetic fields on the surface in addition to surface level changes observed by high-precision geodetic levelling. These studies are now in progress as an aid for earthquake prediction. The role of thermal processes in the upper mantle in these crustal movements is also discussed.

Recent crustal movements, tectonics and seismicity of the western coastal region of peninsular India have been studied in detail in the very recent past. Prominent geomorphic features and large-scale manifestation of Holocene deformation and crustal movements have been noticed and studied over this coastal region from the Gulf of Cambay to the southernmost parts of Kerala, evidence for which is afforded in the form of Recent and sub-Recent raised beaches, sandbars, raised old terraces, pebble beds, etc. The sedimentary formations in this narrow coastal belt include Neogene and Quaternary sediments. The Bouguer gravity map of the western coastal tract shows some prominent gravity features extending into the offshore regions, suggestive of some significant tectonic and structural features. The seismic data in the offshore regions bring out some prominent roughly northwest-southeast as well as east-west faults and shears, in addition to prominent structural “highs” off the Bombay and Ratnagiri coast which have proved oil. The seismicity in this coastal tract as well as the faulted western margin of the western continental shelf in the Arabian Sea is generally of magnitude 3–6.