scholarly journals Climate control on erosion distribution over the Himalaya during the past ∼100 ka: REPLY

Geology ◽  
2010 ◽  
Vol 38 (8) ◽  
pp. e217-e217 ◽  
Author(s):  
Waliur Rahaman ◽  
Sunil K. Singh ◽  
Rajiv Sinha ◽  
S.K. Tandon
Geology ◽  
2009 ◽  
Vol 37 (6) ◽  
pp. 559-562 ◽  
Author(s):  
Waliur Rahaman ◽  
Sunil K. Singh ◽  
Rajiv Sinha ◽  
S.K. Tandon

2019 ◽  
Author(s):  
Lujendra Ojha ◽  
Ken L. Ferrier ◽  
Tank Ojha

Abstract. Over the past two decades, rates and patterns of Himalayan denudation have been documented through numerous cosmogenic nuclide measurements in central and eastern Nepal, Bhutan, and northern India. To date, however, few denudation rates have been measured in Far Western Nepal – a ~ 300-km-wide region near the center of the Himalayan arc – which presents a significant gap in our understanding of Himalayan denudation. Here we report new catchment-averaged millennial-scale denudation rates inferred from cosmogenic 10Be in fluvial quartz at seven sites in Far Western Nepal. The inferred denudation rates range from 385 ± 31 t km−2 yr−1 (0.15 ± 0.01 mm yr −1) to 8737 ± 2908 t km−2 yr−1 (3.3 ± 1.1 mm yr−1), and, in combination with our analyses of channel topography, are broadly consistent with previously published relationships between catchment-averaged denudation rates and normalized channel steepness across the Himalaya. These data show a weak correlation with catchment-averaged specific stream power, consistent with a Himalaya-wide compilation of previously published stream power values. Together, these observations are consistent with a dependence of denudation rate on both tectonic and climatic forcings, and represent a first step toward filling an important gap in denudation rate measurements in Far Western Nepal.


2002 ◽  
Vol 26 ◽  
Author(s):  
Johannes T. Weidinger

Sacred religious monuments such as chorten, and stone-walls (carved with religious inscriptions) can be found all along the Himalaya in and around villages dominated by Buddhist population. These structures are found to have been erected not only around monasteries and other holy places, but also in areas where mountain hazards such as torrent, debris flow and snow avalanche occur. Careful observation of the location of these structures indicate that they were erected also to serve as indicators, silent witnesses and even to protect settlements and farmland from hazards. The reason why this practice is typical for the Buddhistic-Lamaistic region of the Himalaya must partly be due to a wide prevalence of various hazardous geomorphological processes occurring within the Higher Himalaya and Trans Himalayan valleys, which forms the homelands of the Tibetan culture. The position of the sacred structures may be used as a good indicator for the past hazardous events that occurred at a certain time. Some structures also seem to have been built for only a symbolic value. Thus their position can be used for finding or delimiting areas, which may fall in the "red zone" on mapping mountain hazards.


1981 ◽  
Vol 1 (1) ◽  
Author(s):  
Robert M. West ◽  
Jens Munthe

ABSTRACT For the past 150 years, the Siwalik Group, a Miocene through Pleistocene molasse along the flank of the Himalaya has been studied intensively stratigraphically and paleontologically in both India and Pakistan. This work recently has been extended into Nepal, where a presumably complete Siwalik section is present, and a modest number of vertebrate fossils have been found. All but one of Nepalese Siwalik vertebrates hare been collected along the southern edge of the Dang Valley in western Nepal. Two assemblages are now known. The older is of presumed Miocene age and likely equivalent to the fauna of the Chinji Formation in Pakistan. The other is of late Pliocene to early Pleistocene age and similar to the Indian Pinjor fauna. In addition, Plio-Pleistocene vertebrates have been reported from fluvial intermontane deposits in the Kathmandu Valley. As studies of radiometric dating, magnetostratigraphy, physical stratigraphy and fossil distributions are extended into Nepal, the place of the Nepalese Siwaliks and basin deposits will become increasingly clear.


2019 ◽  
Vol 483 (1) ◽  
pp. 423-482 ◽  
Author(s):  
Roger Bilham

AbstractThis article summarizes recent advances in our knowledge of the past 1000 years of earthquakes in the Himalaya using geodetic, historical and seismological data, and identifies segments of the Himalaya that remain unruptured. The width of the Main Himalayan Thrust is quantified along the arc, together with estimates for the bounding coordinates of historical rupture zones, convergence rates, rupture propagation directions as constrained by felt intensities. The 2018 slip potential for fifteen segments of the Himalaya are evaluated and potential magnitudes assessed for future earthquakes should these segments fail in isolation or as contiguous ruptures. Ten of these fifteen segments are sufficiently mature currently to host a great earthquake (Mw ≥ 8). Fatal Himalayan earthquakes have in the past occurred mostly in the daylight hours. The death toll from a future nocturnal earthquake in the Himalaya could possibly exceed 100 000 due to increased populations and the vulnerability of present-day construction methods.


2010 ◽  
Vol 29 (19-20) ◽  
pp. 2484-2498 ◽  
Author(s):  
Alexandra T. Gourlan ◽  
Laure Meynadier ◽  
Claude J. Allègre ◽  
Paul Tapponnier ◽  
Jean-Louis Birck ◽  
...  

2018 ◽  
Vol 2 ◽  
pp. e26440 ◽  
Author(s):  
Barbara Thiers ◽  
Roslyn Rivas ◽  
Elizabeth Kiernan

During the past few years, natural disasters, political or social unrest and institutional actions have imperiled herbaria. The question has been raised multiple times whether or not the data gathered about herbaria in Index Herbariorum could be used to predict which herbaria are at the greatest risk. Armed with such knowledge curators and the greater collections community might be in a better position to safeguard those herbaria. To explore the feasibility of using Index Herbariorum data in this way, we have identified a set of specific threats and then scored herbaria according to their susceptibility to those threats. These threats fall into two categories: Physical and Administrative. Physical threats are those that could lead to loss of collections through outright destruction due to catastrophic events (e.g., earthquake, flood) or loss of the protective controls (e.g., air conditioning, building security) that ensure a safe collections environment. Determination of these threats is based on location. Administrative threats involve decisions made by the governing body to remove staff support, appropriate space or climate control measures for the collection. Physical threats were determined using GIS to plot the location of all herbaria, and then overlaying these with map layers indicating current earthquakes, floods, cyclones and landslides and potential future threats (sea level rise and civil unrest). We deduced Administrative threats from Index Herbariorum data elements. These include the status of the herbarium (active or inactive), whether or not the Index Herbariorum entry for an institution has been updated in the past 10 years, whether or not the herbarium has a designated curator, the ratio of staff to specimens, and whether or not the collection has been digitized. Each threat was assessed as absent or present, and assigned a value of 0 or 1 accordingly. Using this method, less than 4% face no identified threats; 65% face one to three threats and 35% face five or more threats. The criteria used in this study cannot alone predict the future security of a collection, or the lack thereof. The reasons for the loss of a collection are usually more complicated than Index Herbariorum data can convey. However, the large proportion of herbaria that face multiple threats suggests that all herbaria should be aware of the risk factors for their collection, perhaps conducting a self-evaluation using the criteria presented here or others, and where possible should incorporate responses to those threats into their strategic and disaster preparedness plans.


The Holocene ◽  
2020 ◽  
Vol 30 (7) ◽  
pp. 953-965 ◽  
Author(s):  
Tanuj Shukla ◽  
Manish Mehta ◽  
DP Dobhal ◽  
Archna Bohra ◽  
Bhanu Pratap ◽  
...  

We studied a periglacial lake situated in the monsoon-dominated Central Himalaya where an interplay of monsoonal precipitation and glacial fluctuations during the late Holocene is well preserved. A major catastrophe occurred on 16–17 June 2013, with heavy rains causing rupturing of the moraine-dammed Chorabari Lake located in the Mandakini basin, Central Himalaya, and exposed 8-m-thick section of the lacustrine strata. We reconstructed the late-Holocene climatic variability in the region using multi-parametric approach including magnetic, mineralogical and chemical (XRF) properties of sediments, paired with grain size and optically simulated luminescence (OSL) dating. The OSL chronology suggests that the lake was formed by a lateral moraine during the deglaciation phase of Chorabari Glacier between 4.2 and 3.9 ka and thereafter the lake deposited about 8-m-thick sediment sequence in the past 2.3 ka. The climatic reconstruction of the lake broadly represents the late-Holocene glacial chronology of the Central Himalaya coupled with many short-term climatic perturbations recorded at a peri-glacial lake setting. The major climatic phases inferred from the study suggests (1) a cold period between 260 BCE and 270 CE, (2) warmer conditions between 900 and 1260 CE for glacial recession and (3) glacial conditions between ~1370 and 1720 CE when the glacier gained volume probably during the ‘Little Ice Age’ (LIA). We suggest a high glacial sensitivity to climatic variability in the monsoon-dominated region of the Himalaya.


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