Search

In comparison to the east coast, the tsunami hazard for the west coast of India remains under-recognized, despite the impact in 1945 following a Mw 8.1 earthquake in the Makran subduction zone in the northern Arabian Sea. The previous occurrences of tsunamis in the Arabian Sea that would have a bearing on the west coast of India are being debated, including the question whether the Makran region has the potential to generate greater-magnitude earthquakes. With this in the backdrop, we present here the historical and geological evidence of a tsunami impact zone from a site on the Konkan Coast of western India. Located in the village of Kelshi, the impact zone is preserved within a coastal dune complex that also reveals occupation layers. This laterally extending 30–40-cm-thick zone, coinciding with a habitation level, displays varied sedimentary structures including scour-fill features, and is inter-layered with shells, at a height of ~ 3 m from the high-tide level. We attribute these sedimentary features to a tsunami flooding event that was contemporaneous with the transportation of shells, dated at 1508–1681 CE. The geological inference matches with the description by the Portuguese fleets of a sea disturbance in 1524 CE, reported from Dabhol, not far from Kelshi, and also from the Gulf of Cambay, located about 500 km to the north. Precluding submarine landslide scenarios, the modeling results suggest that the high impact in Kelshi could have been generated by a Mw ≥ 9 earthquake sourced in the Makran subduction zone. It is, however, intriguing how a Mw ≥ 9 earthquake in the Makran region finds no mention in the historical documentation. We underscore the need for fresh efforts along the Makran coast to reconstruct the tsunami recurrence history that would generate required validating constraints on the 1524 event, if it was indeed generated by a massive earthquake among other mechanisms.

s The Indian summer monsoon (ISM) precipitation pattern over Indian subcontinent is looked through various high resolution speleothem oxygen (δ18O) isotope records from Mid to Late Holocene. The six cave locations distributed from central to northern India describing regional climatic conditions due to stalagmite deposition are considered. The stalagmite deposition reflects precipitation patterns by temporal variations of δ18O values. Oxygen isotope values reflect cumulative precipitation that is basically interpreted by averaged latitudinal site of inter tropical convergence zone (ITCZ). Under the Paleoclimate Modelling Intercomparison Project Phase III (PMIP3) simulation, Commonwealth Scientific and Industrial Research Organisation Mk3L version 1.0 – Part 2 (CSIRO-Mk3L-1-2) model output shows ITCZ movement from Bay of Bengal (BoB) to Arabian Sea (AS) during Mid to Late Holocene which resulted due to solar insolation changes. It reflects precipitation shift from BoB to AS as well as to core monsoon zone (CMZ) to the western Himalayas. The past millennium epoch, which consists little ice age (LIA) and middle warm period (MWP), shows large variations in 850 hPa geopotential height leading to high anomalous precipitation variability all over India during ISM. The high fluctuation in δ18O values during Mid Holocene over northern India led to drought conditions due to which Indus valley civilization vanished. The present study shows that the Himalayas received higher precipitation during late Holocene. That is basically governed by western disturbances (WD) as well as ISM. Present study summarizes that the mean annual precipitation cycle for entire epoch was roughly similar, but spatial distribution of precipitation during various epoch was quite divergent from Mid to Late Holocene. The onset of ISM was also similar but, withdrawal was comparatively unalike. Wherever, peaks of seasonal precipitation were alike over Indian subcontinent region, spatial distribution of precipitation were unlike.

Understanding the mobility of radiocesium and radiostrontium within geological environment is important from ‘deep geological repository system’—safety assessment point of view. Cs and Sr radionuclide sorption studies have been carried out with a stalagmite sample collected from Lesser—Himalayas. Detailed microstructural studies, backed up by micro-Raman and LIBS analyses, identified three different domains within the sample; constituted of microcrystalline calcite, botryoidal aragonite and palisadic calcite respectively. Experimental studies showed that both the radionuclides exhibit moderate to low sorption coefficients within all the different domains of stalagmite under acidic environment.

In this paper, we reconstruct the climatic changes starting from late Pleistocene to the early Holocene as recorded from a fluvio-lacustrine section located within the Kumaun Central Himalaya. The results suggest two major climatic events corresponding with the Last Glacial Maximum (LGM) and Older Dryas (OD). The values of carbon isotopes vary between -23‰ to -14‰, along with a shift in vegetation pattern. The lower part of the section shows prevalence of C3 type vegetation, indicating warm and moist conditions at around 25,000 yr BP, possibly coinciding with the intensification of the Indian Summer Monsoon. The onset of cold and arid phase is evident in the gradual shift in vegetation pattern from C3 to C4 plants, which is prominently observed in the middle part of the paleolake profile. Eventually, as the value of δ13C during this time interval confirms, a prolonged phase of cold and arid climate sets in, coinciding with the strengthening of winter westerlies. This cold phase is dated at ~19,000 yr BP and the extended phase of cold interval observed at Dwarahat profile correlates well with previous results elsewhere from the Himalaya. The profile also shows that the LGM phase gradually transforms into a warm and moist climate. This transition registered at 200 cm above the base of the profile, marks the end of glacial period. The short, yet a clear warm spike could be related to the oscillation of Bolling-Allerod interstadial at ~15,000 yr BP. A significant negative excursion marked by an abrupt increase in δ13C values from -20‰ to -14‰ observed towards the top part of the profile, however, is reflective of the reduced monsoon precipitation, corresponding possibly with Older Dryas (OD). The topmost part of the profile that registers a depleted trend in δ13C values with dominance of C3 vegetation marks the return of the warm and moist climate.

Stalagmites and stalactites, as observed within natural caves, may develop inside geological repositories during constructional and post-operational periods. It is therefore important to understand actinide sorption within such materials. Towards this, experimental studies were carried out with233U,238Np (VI),238Np (IV),239Pu and241Am radiotracers using natural speleothem samples collected from the Dharamjali cave of the Kumaon Lesser Himalayas, India. Petrological/mineralogical studies showed that natural speleothems have three general domains: (1) columnar calcite; (2) microcrystalline calcite; and (3) botryoidal aragonite – each with ferruginous materials. Results showed that all domains of speleothems can take up >99% actinides, irrespective of valence state and pH (1–6 range) of the solution. However, distribution coefficients were found to be at a maximum in aragonite for most of the actinides. Such data are very important for long-term performance and safety assessments of the deep geological repositories planned for the disposal of high-level nuclear wastes.

The great 1934 Himalayan earthquake of moment magnitude (Mw) 8.1 generated a large zone of ground failure and liquefaction in north Bihar, India, in addition to the earthquakes of 1833 (Mw similar to 7.7) and 1988 (Mw 6.7) that have also impacted this region. Here, we present the results of paleoliquefaction investigations from four sites in the plains of north Bihar and one in eastern Uttar Pradesh. The liquefaction features generated by successive earthquakes were dated at AD 829-971, 886-1090, 907-1181, 1130-1376, 1112-1572, 1492-1672, 1733-1839, and 1814-1854. One of the liquefaction events dated at AD 829-971, 886-1090, and 907-1181 may correlate with the great earthquake of AD similar to 1100, recognized in an earlier study from the sections across the frontal thrust in central eastern Nepal. Two late medieval liquefaction episodes of AD 1130-1376 and 1492-1672 were also exposed in our sites. The sedimentary sections also revealed sandblows that can be attributed to the 1833 earthquake, a lesser magnitude event compared to the 1934. Liquefactions triggered by the 1934 and 1988 earthquakes were evident within the topmost level in some sections. The available data lead us to conjecture that a series of temporally close spaced earthquakes of both strong and large types, not including the infrequent great earthquakes like the 1934, have affected the Bihar Plains during the last 1500 years with a combined recurrence interval of 124 +/- 63 years.

The central part of the Himalaya (Kumaun and Garhwal Provinces of India) is noted for its prolonged seismic quiescence, and therefore, developing a longer-term time series of past earthquakes to understand their recurrence pattern in this segment assumes importance. In addition to direct observations of offsets in stratigraphic exposures or other proxies like paleoliquefaction, deformation preserved within stalagmites (speleothems) in karst system can be analyzed to obtain continuous millennial scale time series of earthquakes. The Central Indian Himalaya hosts natural caves between major active thrusts forming potential storehouses for paleoseismological records. Here, we present results from the limestone caves in the Kumaun Himalaya and discuss the implications of growth perturbations identified in the stalagmites as possible earthquake recorders. This article focuses on three stalagmites from the Dharamjali Cave located in the eastern Kumaun Himalaya, although two other caves, one of them located in the foothills, were also examined for their suitability. The growth anomalies in stalagmites include abrupt tilting or rotation of growth axes, growth termination, and breakage followed by regrowth. The U-Th age data from three specimens allow us to constrain the intervals of growth anomalies, and these were dated at 4273 ± 410 years BP (2673–1853 BC), 2782 ± 79 years BP (851–693 BC), 2498 ± 117 years BP (605–371 BC), 1503 ± 245 years BP (262–752 AD), 1346 ± 101 years BP (563–765 AD), and 687 ± 147 years BP (1176–1470 AD). The dates may correspond to the timings of major/great earthquakes in the region and the youngest event (1176–1470 AD) shows chronological correspondence with either one of the great medieval earthquakes (1050–1250 and 1259–1433 AD) evident from trench excavations across the Himalayan Frontal Thrust.

The similar to 700-km-long ``central seismic gap'' is the most prominent segment of the Himalayan front not to have ruptured in a major earthquake during the last 200-500 yr. This prolonged seismic quiescence has led to the proposition that this region, with a population >10 million, is overdue for a great earthquake. Despite the region's recognized seismic risk, the geometry of faults likely to host large earthquakes remains poorly understood. Here, we place new constraints on the spatial distribution of rock uplift within the western similar to 400 km of the central seismic gap using topographic and river profile analyses together with basinwide erosion rate estimates from cosmogenic Be-10. The data sets show a distinctive physiographic transition at the base of the high Himalaya in the state of Uttarakhand, India, characterized by abrupt strike-normal increases in channel steepness and a tenfold increase in erosion rates. When combined with previously published geophysical imaging and seismicity data sets, we interpret the observed spatial distribution of erosion rates and channel steepness to reflect the landscape response to spatially variable rock uplift due to a structurally coherent ramp-flat system of the Main Himalayan Thrust. Although it remains unresolved whether the kinematics of the Main Himalayan Thrust ramp involve an emergent fault or duplex, the landscape and erosion rate patterns suggest that the decollement beneath the state of Uttarakhand provides a sufficiently large and coherent fault segment capable of hosting a great earthquake.

The present study documents the monsoon precipitation variability spanned ~ 2500 years, between 4.0 and 1.6 ka BP (before 1950 AD), from the Central Lesser Himalaya, India, using δ18O measurements of Tityana cave stalagmite (hereafter referred as TC1). At present, the cave receives precipitation from both Indian Summer Monsoon (ISM) and Western Disturbances (WDs). The δ18O variation between − 8.04 and − 10.46‰ through growth axis of the TC1 and five 14C AMS dates (due to large age uncertainty by 230Th/U method) have allowed us to identify the mid to late Holocene multi-decadal to centennial scale climatic oscillations. The higher δ18O values indicate the weakening of the monsoon precipitation, while the lighter values represent the stronger monsoon precipitation strength. Based on the fluctuations in δ18O values, three distinct phases of the precipitation variability are distinguished as, declined/decreased precipitation between ~ 4.0 and 3.4 ka BP with peak aridity around ~ 3.4 ka BP, followed by slightly improved conditions from ~ 3.4 to ~ 2.7 ka BP. Subsequently, the climate was reduced from ~ 2.7 ka BP onwards until the end of stalagmite growth, around ~ 1.6 ka BP with spikes of two major drought events centred at ~ 1.9 and ~ 1.6 ka BP. In general, the droughts, centred at ~ 3.4, ~ 1.9 and ~ 1.6 ka BP, are characterized by abrupt drop (from − 8.12 to − 8.04‰) in the δ18O values and point to the weakening of the monsoon. One of the major drought events at ~ 3.4 ka BP can be correlated with the collapse of the Indus valley civilization in the NW India. A close correspondence of the TC1 data set with other WDs influenced regimes likely indicates a relative impact of mid-latitude WDs after transition of the mid-late Holocene around 3.5–3.4 ka BP.

The Aravali terrane is a highly deformed Proterozoic mobile belt entangled with an Archaean craton. It is split along its length by a number of crustal-scale shear zones, and dislocation zones developed in it during Precambrian time. Reactivation in the Late Quaternary of the shear zones is manifest in some areas, such as in the sinking of ground with a resultant formation of saline lakes, the bulging up of other areas with attendant watershed migration, the stream capture, the entrenched meander loops, and the persistent moderate to low seismicity in the fault-ridden northeastern part of the Aravali terrane. Separated from this consolidated complex by the Great Boundary Fault, which registers a cumulative throw of 500–1300 m, the vast Vindhyan Basin of Proterozoic sediments is largely undeformed, except for around its tectonic boundary with the Aravali in the west and the Satpura in the south. However, the Vindhyan basement is segmented by wrench faults as well as strike faults, some of which register a strike-slip motion. The pronounced development of badlands close to the northern faulted border against the Ganga Plain indicates a very slow uplift of the northern part.

The geological layouts of Pakistan, Nepal, Bhutan, Bangladesh, and Sri Lanka are inseparably linked with that of India. The Indian subcontinent encompasses as many as nine geological terranes, each having its own distinctive lithological-petrochemical characteristics, structural architecture, and different evolutionary history. There are Archaean cratons embodying composite, consolidated, and rigid blocks; Proterozoic mobile belts of high-grade metamorphic rocks; continent-interior basins comprising slightly deformed to practically undeformed Proterozoic sediments; Permian-age elongate Gondwanic grabens and half-grabens cutting across the cratons; a Cretaceous Volcanic Province covering vast swathes of land in western and central India; Mesozoic–Cenozoic sediments piled up on gradually sinking continental margins; a Cenozoic Himalayan Mobile Belt representing a youthful orogen formed due to the docking of India with Asia; flysch-dominated obduction complexes forming the much-faulted arcuate mountain ranges along the India–Myanmar border; and an oceanic trench-defined island-arc complex in the Bay of Bengal.

Between the 1000-km-long ENE–WSW-trending Narmada Graben in the north and much smaller but parallel Tapi Graben in the southwest, the Proterozoic Satpura Mobile Belt forms a prominent horst that rose up rapidly in the Later Quaternary time. Delimited by faults that are responsible for 500–800 m of cumulative throw, the Narmada Graben is a narrow zone of high heat flow, hot springs, parallel dyke swarms, and moderate seismicity. In the domain of this rift valley, the main river follows a remarkably straight course all along the reach, but its tributaries swerve abruptly before joining the Narmada across the Pleistocene terraces. Strong movements on the Tapi graben faults, which were accompanied by great earthquakes, resulted in an unusual continental-scale drainage pattern that created a large westwards-flowing catchment in the region where all other rivers flow either northeastwards or southeastwards. Shear zones of a large dimension south of the Satpura horst are seismogenic.

Made up of high-grade metamorphic rocks that evolved under ultra-high temperatures, the highly dissected Precambrian Eastern Ghat Mobile Belt is demarcated against the Dharwar–Bastar cratons by west-vergent shear zones dotted with plutons of alkaline and ultrabasic rocks, as well as against the Proterozoic Cuddapah sedimentary basin by a fold-and-thrust zone. A few NW–SE-oriented grabens that cut across the terrane served as floodplains of rivers like the Krishna and Godavari. In the coast of emergence that is the East Coast, lakes representing drowned embayments, sunken karstic topography with its pinnacles and domes, submerged V-shaped canyons offshore of the Krishna–Godavari domain, and archaeological remains of a seaport 30 m below the surface in the Kaveri delta, point to the sinking that continued into historical time. On the other hand, raised beaches, high strand lines, and progressive river migration in their deltas indicate uplift in some parts that are fault ridden. Seismicity in the southeastern part of the Godavari Graben and in east central Tamil Nadu indicates that some faults are very active.

Extending westwards into northern Pakistan, the Himalaya Mobile Belt with its rock formations, multiple thrusts, and Indus–Tsangpo Suture bends southwards, forming the spectacular Hazara Syntaxis. Continuing stress buildup is reflected in fast uplift, very high seismicity, large-scale recurrent slope failures, and the resultant mass movements and consequent stream blockages in the region of Nanga Parbat–Haramosh massif. The flexed Sulaiman–Kirthar mountain-forming festoons in west central Pakistan are cut by a multiplicity of N–S trending transverse faults, most of which are very active and seismogenic. The most important of these tear faults is the ~ 900-km-long transcurrent left-lateral Chaman Fault, which has caused a cumulative displacement of the order of 460 km, as borne out by dislocation of very young landforms and rock formations, drainage deflections, and extraordinarily high seismicity. Framing the oceanic Oman Trench, the Makran Coastal Ranges in the south represent an accretionary prism of the obducted material, split up by the multiplicity of steep strike faults. This complex continues to register vertical movements, as testified by repeat earthquakes and raised marine beaches.

The Ganga–Brahmaputra Plains represent a sediment-filled foreland basin in front of the Himalaya. Characterized by disparate physigraphic units and occurring as large terraces at different elevation levels belonging to different chronological times of the Late Quaternary epoch, the Plains conceal under the thick pile of fluvial and alluvial sediments a number of very high NE–SW-trending basement ridges delimited by long, deep faults. Continual and episodic differential movements on these faults with an attendant rise and subsidence of ground caused the persistent shifting of the rivers of the Yamuna and Ganga systems eastwards and of the Gandak–Kosi and Brahmaputra systems westwards. The neotectonic movements also brought about drainage obstruction, culminating in the development of swamps, marshes, lakes, and waterlogging in the much-faulted Kosi–Gandak domain as well as in northern Bangladesh. The abandonment by the Brahmaputra River of its former course and joining with Ganga River in Bangladesh was a result of tremendous neotectonic resurgence in the Bengal Basin. Palaeoseismites in the foothill belt all along the length of the Ganga–Brahmaputra plains point to the havoc wreaked by many seismogenic faults that riddle the northern periphery of the Ganga–Brahmaputra Plains.

The 2400-km-long and 300-km-wide arcuate Himalayan Mobile Belt is delimited against the Asian plate by the Indus–Tsangpo Suture, the zone of docking of India with mainland Asia. It is separated from the Indo-Gangetic Plains by Himalayan Frontal Thrust. The young mobile belt is characterized by spectacular syntaxial bends at its eastern and western extremities and by salients and re-entrants at its southern front. Such long and deep rupture planes as the Main Boundary Thrust, Main Central Thrust, and Trans-Himadri Detachment Fault subdivide the mountain province into four physiographically contrasted and lithotectonically distinctive terranes or subprovinces known as the Siwalik, the Lesser Himalaya, the Great Himalaya, and the Tethys Himalaya. Characterized by altogether different structural architecture and tectonic history, all these four terranes are tectonically more or less resurgent, with the Great Himalaya being the most active and rising up at a much faster rate. Occurrence of intermontane basins of sedimentary fills, tectonic lakes and river ponding with palaeolake deposits, stepped terraces lining rivers upstream of faults, and dissection–dislocation of colluvial and fluvial fans, and the rocks of great antiquity riding upon subrecent gravel deposits in the proximity of active faults testify to Late Quaternary to Mid-Holocene movements. Continuing strong seismicity in fault-ridden belts, in addition to GPS measurements, point to persistent and strong movements in all the four terranes of the youngest mountain province of the Indian subcontinent. This is because the mountain province is continually pressed by the northward-moving Indian Peninsula.

Representing the southerly extension of the desertic Rajasthan plain, the Sabarmati plain in Gujarat conceals a N–S-trending, 50-km-wide graben defined by down-to-basin faults. Listric faults and ENE–WSW-oriented wrench faults have appreciably affected this hidden graben, which is in the line of similar grabens in westen Rajasthan. The 2000- to 3000-m-thick succession of Cenozoic sediments of this graben hosts petroleum and gas deposits. Repeated reactivation, including during the Later Holocene era, of the faults of the graben domain is evident from the southwestward tilting of the floodplain, the deflection and deep incision of the stream channels, the occurrence of palaeoseismites in the proximity of the graben-boundary faults, and a continuing seismicity. Belonging to the stable continental region of Peninsular India, the Saurashtra region exhibits microseismicity in a few geographically limited areas. Radically different in every respect and bearing a strong resemblance to the Himalayan mobile domain, the Kachchh (Cutch/Kutch) terrane is cut by a number of E–W-trending deep faults, giving rise to hill ranges in the southern part and a sunken tract known as Rann in the northern and eastern parts, which were under seawater until early historical times. The youthful geomorphology of horst-like hill ranges, drainage deviation, deep incision of subrecent colluvial–alluvial fans by perennial streams in the desertic terrain, palaeoseismites, and a continuing strong seismicity indicate that Kachchh (Cutch/Kutch) is tectonically the most resurgent part of Peninsular India.

Forming a tableland in western India, the lava piles of the Upper Cretaceous Deccan Volcanic Province are undeformed except along its western margin in Maharashtra. Repeated vertical movement on a multiplicy of NNW–SSE-trending rupture planes in the western margin of the Deccan Plateau culminated in the emergence of the high Sahyadri ranges and an attendant slight westward local tilting of the lava pile along the continental margin. The reactivation of the rupture planes and of the delimiting faults of NNW/NW to SSE/SE-trending hidden (subsurface) grabens developed in the Archaean basement underneath the thick lava pile is responsible for the tectonic resurgence of the Upland Maharashtra and adjoining belts. This is manifest in the formation of waterfalls and prominent knickpoints close to river sources, deep incisions in wide terraced valleys, entrenched meanders in east-flowing rivers, and elongate pockets of high seismicity, in addition to the occurrence of palaeoseismites at various stratigraphic levels in two faulted belts.

Genetically connected to the India–Myanmar Border Ranges in the north and to the Indonesian Archipelago in the southeast, the Andaman–Nicobar Island Arc comprises an imbricated pack of Upper Cretaceous to Early Tertiary flysch successions that is implanted with ophiolites. This accretionary prism is split by numerous listric faults and thrusts, and is defined in the west by a 4000-m-deep oceanic trench, known as the Java Trench. This deep depression represents a subduction zone. To the east lies an arc of dormant and active volcanoes related to seafloor spreading in the back-arc basin, the Andaman Sea. The seafloor in the Bay of Bengal is intermittently sliding under the Andaman accretionary prism, as manifest in very high seismicity, including the great earthquakes of December 2004 M 9.3. This event is related to an 800-km-long rupturing of the oceanic crust. GPS measurements confirm a fast oblique convergence eastwards.

Underneath the floodplains of the Sindhu and Ghagghar river systems, a number of subsurface basement ridges are related to the NW–SE-trending Aravali Mobile Belt. A multiplicity of long and deep faults also occurs. Seismicity in parts of the belts over these hidden ridges indicates the reactivation of faults across which flow the rivers of the two systems. Although the Sindhu River migrated 160 km westwards in the Holocene time, even as great subsurface depressions formed in front of the Sulaiman and Kirthar Ranges, the Ghagghar basin in the eastern part witnessed a strong tectonic upheaval. This manifested itself in subsidence, uplift and dislocation of ground. This resulted in drainage reorganization, channel segmentation, and, in one case, river piracy. This spectacular event happened at a time when a drastic decline in rainfall occurred, which caused not only a mass exodus of the people of the Harappan civilization in the mid-Holocene time, but also the development of the Thar Desert in western India and adjoining Pakistan.

The N–S trending array of mountain ranges along the border of India and Myanmar represents the eastern arm of the Himalayan Mobile Belt. A linkage of three disparate mountain belts forming the Siang Syntaxis in the north separates this arcuate arm from the main Himalayan arc. Characterized by a schuppen structure (i.e., packs of imbricated thrust sheets that are folded and faulted), this orogenic unit of Late Mesozoic–Cenozoic flysch with its ophiolite implants is strongly affected by stresses generated due to the oblique convergence and attendant underthrusting of the Indian plate under the Burmese (Myanmar) microplate. The rate of slipping varies not only from sector to sector, but also from time to time. Very high seismicity and GPS measurements demonstrate continuing strong movements on faults of this fault-ridden palaeo-obduction complex. The epicentral distribution defines a distinct Benioff Zone dipping eastwards under Myanmar.

The early Precambrian Bastar and Singhbhum cratons, with their intimately associated Proterozoic mobile belts, are subdivided into disparate terranes by a number of long, deep, and curvilinear shear zones of Precambrian antiquity. Although the orthogonal Gondwanic Godavari Graben defines the western limit of the Bastar, the Mahanadi Graben separates the Bastar from the Singhbhum domain. Despite a multiplicity of terrane-defining curvilinear seismogenic shear zones, no work on neotectonism has been done in this part of the Indian subcontinent. A notable feature is that the laterite-mantled terrain characterized by many planation surfaces and delimited by escarpments has become rugged in some belts. Down these scarp faces descend rivers and streams as waterfalls. All these features collectively indicate the Late Quaternary uplift. In a sector of the E–W-trending, much-faulted Damodar Graben in the Singhbhum domain, palaeochannels are associated with archaeological remnants, implying tectonic disturbance in historical time in the graben zone.

Close to the Arabian Sea coast, the peaks of the 1600-km-long chain of the Sahyadri Ranges rise to an elevation of 1646 m in northern sector, 1646 m in the central sector, and 2695 m in the southern sector. It is cut by the E–W-trending, continent-wide Precambrian shear zones in the Palghat Gap which is no more than 75–300 m above sea level. Rising high against the 40–120 m of undulating terrain of the coast of emergence, the 900- to 2695-m high Sahyadri is remarkable for its spectacular western flank that is characterized by high escarpments alternating with narrow, irregularly tilted terraces forming a ‘landing stair’ (ghat) geomorphic architecture known as the Western Ghat. The Sahyadri terrane is split into a number of linear blocks by NW–SE, NNW–SSE, and N–S-trending faults and fractures. It is a product of the differential–intermittent uplift on these faults, predominantly in the Quaternary era. These rupture planes extend northwestwards through the coastal belt on to the offshore to form underwater basins (rifts) and ridges (horsts). Raised beaches, drowned forests, anomalous stream deflections, palaeolake deposits, and a continuing blockage of rivers at their fault crossing, geothermal springs, high emission of radon gas, and high seismicity in the much faulted areas in the coastal belt and Sahyadri domain eloquently testify to tectonic resurgence the two belts have witnessed and continue to undergo.

Stable isotopes from a U/Th dated aragonite stalagmite from the Central Kumaun Himalaya provide evidence of variation in climatic conditions in the last similar to 1800 years. The delta O-18 and delta C-13 values vary from -4.3 parts per thousand to -7.6 parts per thousand and -3.4 parts per thousand to -9.1 parts per thousand respectively, although the stalagmite was not grown in isotopic equilibrium with cave drip water, a clear palaeoclimatic signal in stalagmite delta O-18 values is evident based on the regional climate data. The stalagmite showed a rapid growth rate during 830-910 AD, most likely the lower part of Medieval Warm Period (MWP), and 1600-1640 AD, the middle part of Little Ice Age (LIA). Two distinct phases of reduced precipitation are marked by a 2 parts per thousand shift in 8180 values towards the end of MWP (similar to 1080-1160 AD) and after its termination from similar to 1210 to 1440 AD. The LIA (similar to 1440-1880 AD) is represented by sub-tropical climate similar to modern conditions, whereas the post-LIA was comparatively drier. The Inter Tropical Convergence Zone (ITCZ) was located over the cave location during wetter/warmer conditions. When it shifted southward, precipitation over the study area decreased. A prominent drop in delta O-18 and delta C-13 values during the post-LIA period may also have been additionally influenced by anthropogenic activity in the area. (C) 2013 Elsevier Ltd and INQUA. All rights reserved.

Investigated for d18O and d13C isotopes, mineralogy and growth rate, a 20 cm long and 230Th-dated calcite stalagmite from Kalakot (Jammu and Kashmir Himalaya), has recorded high resolution precipitation variability during the Pleistocene-Holocene transition. At present, the study area is influenced by both the Indian Summer Monsoon (ISM) and Westerlies. The StalAge model indicates that the stalagmite grew between 16.3 ka to 9.5 ka BP under the ideal isotopic equilibrium conditions as revealed by the Hendy test results. The d18O and d13C values range from -5.41 to -8.82% and -7.09 to -10.84% respectively. Although the U/Th chronology is poor due to low Uranium content in the samples resulting in relatively large errors, the first stalagmite inferred precipitation variability reconstructed from NW Indian Himalaya makes this study significant. The near footprints of three global events, e.g., Older Dryas (OD), Allerod period and Younger Drays (YD) can be noticed at ~14.3-13.9, 13.9-12.7 and 12.7-12.2 ka BP. The precipitation strength was weaker during the OD and YD, but was stronger during the Allerod interstadial. By the termination of YD interval, the climate seems fluctuating in the NW Himalaya. There seems variation in commencement, duration and termination of the above mentioned events in different parts of the globe due to latitude location and response time.

This paper presents the first stable isotope (delta O-18 and delta C-13) data of a similar to 400 years (1590-2006 AD) long annual to decadal-resolution speleothem record collected from the Indian Lesser Himalaya. The data show a variation from -2.7 to -5.9 parts per thousand in delta O-18 and -5.3 to -8.8 parts per thousand in delta C-13. The isotopic analyses indicate that the climate during this period can be divided into two stages: a wet phase during the Little Ice Age (LIA) (1590-1850 AD) and comparatively dry phase during the post-LIA after 1850 AD. However, the record also documents the minor dry events during the LIA and a wet episode after the LIA. Within the age uncertainty, the dry spells during the LIA are linked with the historical drought events in the Indian subcontinent and similar latitudes. The isotopic record is consistent with a number of previous studies in the areas influenced by the Westerlies but appears to be conflicting to the regions, dominated by the Indian Summer Monsoon (ISM). This may be due to the possible changes in the strength of Westerlies in the study area and added by negative anomaly of North Atlantic Oscillation (NAO) during the LIA. (C) 2012 Elsevier Ltd and INQUA. All rights reserved.

106Ru, 144Ce and 152+154Eu radiotracers sorption experiments (pH: 1–6) have been carried out with polycrystalline columnar/microcrystalline calcite and aragonite obtained from a stalagmite of Dharamjali cave, India. The different domains of the sample were powdered and thoroughly studied using electron microscopic and X-ray spectroscopic techniques. Both 106Ru and 144Ce exhibited higher sorption within calcite varieties compared to aragonite and increased with rising pH, while it showed reverse relation in case of 152+154Eu. Further, it is noted that aragonite offers the highest K d values for 152+154Eu, whereas 106Ru and 144Ce prefer calcite.

Literature of the ancient Chola Dynasty (A.D. 9th-11th centuries) of South India and recent archaeological excavations allude to a sea flood that crippled the ancient port at Kaveripattinam, a trading hub for Southeast Asia, and probably affected the entire South Indian coast, analogous to the 2004 Indian Ocean tsunami impact. We present sedimentary evidence from an archaeological site to validate the textual references to this early medieval event. A sandy layer showing bed forms representing high-energy conditions, possibly generated by a seaborne wave, was identified at the Kaveripattinam coast of Tamil Nadu, South India. Its sedimentary characteristics include hummocky cross-stratification, convolute lamination with heavy minerals, rip-up clasts, an erosional contact with the underlying mud bed, and a landward thinning geometry. Admixed with 1000-year-old Chola period artifacts, it provided an optically stimulated luminescence age of 1091 perpendicular to 66 yr and a thermoluminescence age of 993 perpendicular to 73 yr for the embedded pottery sherds. The dates of these proxies converge around 1000 yr B. P., correlative of an ancient tsunami reported from elsewhere along the Indian Ocean coasts. (C) 2011 Wiley Periodicals, Inc.

An event of neotectonic activity on an NE–SW trending subsidiary fault in the zone of E–W running intracrustal boundary thrust (South Almora Thrust) in the Champawat district of eastern Kumaun Himalaya resulted in creation of a lake at ca. 21.5 BP. The lake drained in the late Holocene, leaving behind a 5.0 m thick sedimentary sequence of mostly black and carbonaceous mud, with a minor magnetic reversal between 20.5 and 19.7 ka BP at the base. The profile, studied by using multi-proxies (e.g., carbon isotopes, pollen analysis, palaeo and mineral magnetism and clay minerals) has recorded globally well established abrupt climatic events in the last 20,000 years, such as the LGM, Older Dryas (OD), Younger Dryas (YD), Holocene warming, 8.2 ka, and 4.2 ka events. Most events, estimated assuming a constant rate of sediment accumulation for similar lithologies, may be related to the rapid changes in the local climate and albedo structure. The ITCZ may have played a key role in controlling the behavior of the southwest monsoon from the LGM.

The youngest fossil Golunda (Rodentia, Muridae) is described from the Late Pleistocene fluvio-lacustrine deposits, exposed at Dulam (Bageshwar), Kumaun Lesser Himalaya, India. The age of fossiliferrous horizon is estimated as 31,000 yr BP. A new species, Golunda dulamensis nov. sp. has highly derived characters, e.g., antero-posteriorly stretched molars, upper molars with more length and less width, stephanodonty, cusps in M 3 strongly inclined backward giving the molars a very stretched aspect, and metaconid and entoconid in M 3 forming almost straight lingual row of the cusps. G . dulamensis nov. sp. is most similar to present day G . ellioti but differs from the later slightly by larger size, a thin connection between t 4 and t 5 in M 1 , and comparatively larger entoconid and very weakly developed antero-labial cusp in M 3 . We suggest that highly specialized molars of G . dulamensis nov. sp. and present day G . ellioti are derivable through G . kelleri . We also propose that Golunda migrated from Asia to Africa, not from Africa to Asia as was thought by earlier workers.

Global Positioning System‐based convergence rate between India and southern Tibet is estimated as 20±3 mm/yr (Larson et al. , 1999). Despite this fast convergence, the seismicity rate of the Himalaya has been remarkably low, as only ∼50% of this plate boundary has ruptured during the last 200 years. This long‐lived deficit in seismic productivity has led many to believe that the region holds potential for more than one magnitude≥8.0 earthquake (Ambraseys and Jackson, 2003). The Himalaya plate boundary has generated three great earthquakes during the last century; however, since the 1950 Assam earthquake ( M w 8.0), there has been quiescence, with the gap in time and space particularly noted on its central segment. Khattri (1987) proposed that the region comprising the Garhwal and Kumaun provinces and the western parts of Nepal falls in a seismic gap. Referred to as the “Central Gap,” this region covers ∼600 km length of the Himalayan arc, and it arguably represents an unruptured segment between the sources of the 1905 Kangra M 7.8 and 1934 Nepal–Bihar M 8.0 earthquakes (Fig. 1). However, the extent to which older earthquakes might have filled the gap is contested on various counts. The uncertainties in locations and magnitudes of pre‐twentieth century earthquakes; in particular the 1803 and 1505 events, are also being debated (Ambraseys and Douglas, 2004; Rajendran and Rajendran, 2005, 2011). Considering the large and densely populated regions that are likely to be affected, reconstructing the seismic history of the Himalaya is a key issue in the seismic‐hazard assessment. Figure 1. Locations of the significant earthquakes in the central Himalaya and the study area, comprising the Garhwal–Kumaun provinces. The history and cultural heritage of the regions within the central gap is much longer than the currently estimated interseismic interval of ∼500 years for great earthquakes; and, therefore, it provides opportunity to …