scholarly journals Characteristics of surface damage in China during the 25 April 2015 Nepal earthquake

2018 ◽  
Author(s):  
Zhonghai Wu ◽  
Patrick J. Barosh ◽  
Xin Yao ◽  
Yongqiang Xu
Keyword(s):  
Monsoon Season ◽  
Surface Damage ◽  
Normal Faults ◽  
Southern Tibet ◽  
Ground Fissures ◽  
Nepal Earthquake ◽  
Southern Border ◽  
Populated Region ◽  
Pass Through ◽  
The Himalaya

Abstract. The seismic effects in Nyalam, Gyirong, Tingri and Dinggye counties along the southern border of Tibet were investigated during 2–8 May, 2015, a week after the great Nepal earthquake along the Main Himalaya Thrust. The intensity was VIII in the region and reached IX at two towns on the Nepal border; resulting in the destruction of 2700 buildings, seriously damaging over 40 000 others, while killing 27 people and injuring 856 in this sparsely populated region. The main geologic effects in this steep rugged region are collapses, landslides, rockfalls, and ground fissures; many of which are reactivations of older land slips. These did great damage to the buildings, roads and bridges in the region. Most of the effects are along four incised valleys which are controlled by N–S trending rifts and contain rivers that pass through the Himalaya Mountains and flow into Nepal; at least two of the larger aftershocks occurred along the normal faults. Areas weakened by the earthquake pose post-seismic hazards. Three valleys have the potential for dangerous post-seismic debris flows that could create dangerous dams especially during the monsoon season. Loosened rock and older slides also may fail. In addition, there is an increased seismic hazard along active N–S trending grabens in southern Tibet due to the shift in stress resulting from the thrust movement that caused the Nepal earthquake. NW trending right-lateral strike-slip faults also may be susceptible to movement. The results of the findings are incorporated in some principle recommendations for the repair and reconstruction after the earthquake.

scholarly journals Damage induced by the 25 April 2015 Nepal earthquake in the Tibetan border region of China and increased post-seismic hazards

2019 ◽  
Vol 19 (4) ◽  
pp. 873-888 ◽  
Author(s):  
Zhonghai Wu ◽  
Patrick J. Barosh ◽  
Guanghao Ha ◽  
Xin Yao ◽  
Yongqiang Xu ◽  
...  
Keyword(s):  
Seismic Hazards ◽  
Border Region ◽  
Normal Faults ◽  
Southern Tibet ◽  
Ground Fissures ◽  
Nepal Earthquake ◽  
Southern Border ◽  
Populated Region ◽  
Pass Through ◽  
The Himalaya

Abstract. The seismic effects in Nyalam, Gyirong, Tingri and Dinggye counties along the southern border of Tibet were investigated during 2–8 May 2015, a week after the great Nepal earthquake along the Main Himalaya Thrust. The intensity was VIII in the region and reached IX at two towns on the Nepal border, resulting in the destruction of 2700 buildings, seriously damaging over 40 000 others, while killing 27 people and injuring 856 in this sparsely populated region. The main geologic effects in this steep rugged region are collapses, landslides, rockfalls, and ground fissures, many of which are reactivations of older land slips. These did great damage to the buildings, roads, and bridges in the region. Most of the effects are along four incised valleys which are controlled by N-trending rifts and contain rivers that pass through the Himalaya Mountains and flow into Nepal; at least two of the larger aftershocks occurred along the normal faults. And, the damage is not related to the faulting of N-trending rifts but rather is distributed along the intensity of Nepal earthquake. Areas weakened by the earthquake pose post-seismic hazards. Another main characteristic of damage is the recurrence of the old landslide and rockfalls. In addition, there is an increased seismic hazard along active N-trending grabens in southern Tibet due to the shift in stress resulting from the thrust movement that caused the Nepal earthquake. NW-trending right-lateral strike-slip faults also may be susceptible to movement. The results of the findings are incorporated in some principle recommendations for the repair and reconstruction after the earthquake.

scholarly journals Non-protein components of the cell surface of Staphylococcus aureus

1968 ◽  
Vol 107 (6) ◽  
pp. 817-821 ◽  
Author(s):  
A. M. James ◽  
J. E. Brewer
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Surface ◽  
Teichoic Acid ◽  
Surface Damage ◽  
Sodium Metaperiodate ◽  
Maximum Value ◽  
Dependent Change ◽  
Ph Dependent ◽  
Pass Through ◽  
Protein Components

1. pH–mobility curves of various laboratory strains of Staphylococcus aureus are non-sigmoid in shape, and all pass through a maximum value in the range pH4–5. 2. The maxima in the curves are not due to incomplete washing of the cells, adsorption of buffer components or irreversible surface damage. 3. Mild oxidation of the cell-surface teichoic acid with sodium metaperiodate gives cells that have typical sigmoid pH–mobility curves, characteristic of either a simple carboxyl surface or a mixed carboxyl–amino surface. 4. The results are discussed in terms of a pH-dependent change in the configuration of the teichoic acid molecules at the surface.

Structure of the North Indian continental margin in the Ladakh–Zanskar Himalayas: implications for the timing of obduction of the Spontang ophiolite, India–Asia collision and deformation events in the Himalaya

1997 ◽  
Vol 134 (3) ◽  
pp. 297-316 ◽  
Author(s):  
MIKE SEARLE ◽  
RICHARD I. CORFIELD ◽  
BEN STEPHENSON ◽  
JOE MCCARRON
Keyword(s):  
Continental Margin ◽  
Suture Zone ◽  
Indian Plate ◽  
Normal Faults ◽  
Initial Contact ◽  
Crustal Shortening ◽  
Northern Margin ◽  
The North ◽  
Late Tertiary ◽  
The Himalaya

The collision of India and Asia can be defined as a process that started with the closing of the Tethyan ocean that, during Mesozoic and early Tertiary times, separated the two continental plates. Following initial contact of Indian and Asian continental crust, the Indian plate continued its northward drift into Asia, a process which continues to this day. In the Ladakh–Zanskar Himalaya the youngest marine sediments, both in the Indus suture zone and along the northern continental margin of India, are lowermost Eocene Nummulitic limestones dated at ∼54 Ma. Along the north Indian shelf margin, southwest-facing folded Palaeocene–Lower Eocene shallow-marine limestones unconformably overlie highly deformed Mesozoic shelf carbonates and allochthonous Upper Cretaceous shales, indicating an initial deformation event during the latest Cretaceous–early Palaeocene, corresponding with the timing of obduction of the Spontang ophiolite onto the Indian margin. It is suggested here that all the ophiolites from Oman, along western Pakistan (Bela, Muslim Bagh, Zhob and Waziristan) to the Spontang and Amlang-la ophiolites in the Himalaya were obducted during the late Cretaceous and earliest Palaeocene, prior to the closing of Tethys.The major phase of crustal shortening followed the India–Asia collision producing spectacular folds and thrusts across the Zanskar range. A new structural profile across the Indian continental margin along the Zanskar River gorge is presented here. Four main units are separated by major detachments including both normal faults (e.g. Zanskar, Karsha Detachments), southwest-directed thrusts reactivated as northeast-directed normal faults (e.g. Zangla Detachment), breakback thrusts (e.g. Photoksar Thrust) and late Tertiary backthrusts (e.g. Zanskar Backthrust). The normal faults place younger rocks onto older and separate two units, both showing compressional tectonics, but have no net crustal extension across them. Rather, they are related to rapid exhumation of the structurally lower, middle and deep crustal metamorphic rocks of the High Himalaya along the footwall of the Zanskar Detachment. The backthrusting affects the northern margin of the Zanskar shelf and the entire Indus suture zone, including the mid-Eocene–Miocene post-collisional fluvial and lacustrine molasse sediments (Indus Group), and therefore must be Pliocene–Pleistocene in age. Minimum amounts of crustal shortening across the Indian continental margin are 150–170 km although extreme ductile folding makes any balancing exercise questionable.

scholarly journals II. On the connexion of the Himalaya snowfall with dry winds and seasons of drought in India

1884 ◽  
Vol 37 (232-234) ◽  
pp. 3-22 ◽  
Keyword(s):  
Monsoon Season ◽  
India Meteorological Department ◽  
Climatic Conditions ◽  
General Idea ◽  
Annual Reports ◽  
Western India ◽  
The Subject ◽  
The Government ◽  
The Himalaya ◽  
North Western

The present paper, as regards its subject-matter though not in form, is part of a general investigation of the rainfall of India, which has occupied much of my spare time for some years past, and the results of which are already partly embodied in a memoir which I hope, in the course of a few months, to issue as an official publication of the Indian Meteorological Office. The idea that the snowfall of the Himalaya exercises a direct and important influence on the dry land winds of North-Western India is not now put forward for the first time. It has been the subject of frequent reference in the annual reports on the meteorology of India since 1876, as well as elsewhere; and in a report on the administration of the India Meteorological Department lately issued, I summarised very briefly those points in the experience of the previous five years which have seemed to justify its provisional adoption as a basis for forecasting the probable character of the monsoon rains. Relying on this experience, in the month of June last, I put forward in the Government Gazette, a note giving warning of the probability of a prolonged period of drought in the approaching monsoon season, and the result, if not in exact accordance with the terms of the forecast, has been so far confirmatory of the general idea, as to induce me to put the facts of past experience formally on record, and thereby challenge attention to the subject. If I am right in the inference that the varying extent and thickness of the Himalayan snows exercise a great and prolonged influence on the climatic conditions and weather of the plains of North-Western India, it is probable, that with more or less modification according to the local geography, causes of a similar character will be found equally operative in other regions, and perhaps on an even more extensive scale.

scholarly journals Similarities and differences of aerosol optical properties between southern and northern sides of the Himalayas

2014 ◽  
Vol 14 (6) ◽  
pp. 3133-3149 ◽  
Author(s):  
C. Xu ◽  
Y. M. Ma ◽  
A. Panday ◽  
Z. Y. Cong ◽  
K. Yang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Monsoon Season ◽  
Diurnal Variations ◽  
The Other ◽  
The Tibetan Plateau ◽  
Aerosol Optical Properties ◽  
Coarse Mode ◽  
Southern Side ◽  
Northern Side ◽  
The Himalaya

Abstract. The Himalaya mountains along the southern edge of the Tibetan Plateau act as a natural barrier for the transport of atmospheric aerosols from the polluted regions of South Asia to the main body of the Tibetan Plateau. In this study, we investigate the seasonal and diurnal variations of aerosol optical properties measured at two Aerosol Robotic Network (AERONET) sites on the southern side of the Himalaya (Pokhara, 812 m above sea level (a.s.l.) and EVK2-CNR, 5079 m a.s.l. in Nepal) and one on the northern side (Qomolangma (Mt. Everest) station for Atmospheric and Environmental Observation and Research, Chinese Academy of Sciences (QOMS_CAS) in Tibet, 4076 m a.s.l. in China). While observations at QOMS_CAS and EVK2-CNR can generally be representative of a remote background atmosphere, Pokhara is a lower-elevation suburban site with much higher aerosol load due to both the influence of local anthropogenic activities and to its proximity to the Indo-Gangetic Plains. The annual mean aerosol optical depth (AOD) during the investigated period was 0.05 at QOMS_CAS, 0.04 at EVK2-CNR and 0.51 at Pokhara, respectively. Seasonal variations of aerosols are profoundly affected by large-scale atmospheric circulation. Vegetation fires, peaking during April in the Himalayan region and northern India, contribute to a growing fine mode AOD at the three stations. Dust transported to these sites, wind erosion and hydrated/cloud-processed aerosols lead to an increase in coarse mode AOD during the monsoon season at QOMS_CAS and EVK2-CNR. Meanwhile, coarse mode AOD at EVK2-CNR is higher than at QOMS_CAS in August and September, indicating that the transport of coarse mode aerosols from the southern to the northern side may be effectively reduced. The effect of precipitation scavenging is clearly seen at Pokhara, which sees significantly reduced aerosol loads during the monsoon season. Unlike the seasonal variations, diurnal variations are mainly influenced by meso-scale systems and local topography. The diurnal pattern in precipitation appears to contribute to diurnal changes in AOD through the effect of precipitation scavenging. AOD exhibits diurnal patterns related to emissions in Pokhara, while it does not at the other two high-altitude sites. At EVK2-CNR, the daytime airflow carries aerosols up from lower-altitude polluted regions, leading to increasing AOD, while the other two stations are less influenced by valley winds. Surface heating influences the local convection, which further controls the vertical aerosol exchange and the diffusion rate of pollution to the surrounding areas. Fine and coarse mode particles are mixed together on the southern side of the Himalaya in spring, which may lead to the greater inter-annual difference in diurnal cycles of Ångström exponent (AE) at EVK2-CNR than that at QOMS_CAS.

Increasing seismicity in Southern Tibet following the 2015 Mw 7.8 Gorkha, Nepal earthquake

2017 ◽  
Vol 714-715 ◽  
pp. 62-70 ◽  
Author(s):  
Lu Li ◽  
Dongdong Yao ◽  
Xiaofeng Meng ◽  
Zhigang Peng ◽  
Baoshan Wang
Keyword(s):  
Southern Tibet ◽  
Nepal Earthquake

scholarly journals The Timing of Metamorphism, Magmatism, and Cooling in the Zanskar, Garhwal, and Nepal Himalaya

1995 ◽  
Vol 11 ◽  
Author(s):  
M. P. Searle
Keyword(s):  
Hanging Wall ◽  
Crustal Thickening ◽  
Indian Plate ◽  
Eastern Himalaya ◽  
Normal Faults ◽  
The Tibetan Plateau ◽  
Main Central Thrust ◽  
Southern Tibet ◽  
Peak Metamorphism ◽  
Exhumation Rates

Following India-Asia collision, which is estimated at ca. 54-50 Ma in the Ladakh-southern Tibet area, crustal thickening and timing of peak metamorphism may have been diachronous both along the Himalaya (pre-40 Ma north Pakistan; pre-31 Ma Zanskar; pre-20 Ma east Kashmir, west Garhwal; 11-4 Ma Nanga Parbat) and cross the strike of the High Himalaya, propagating S (in Zanskar SW) with time. Thrusting along the base of the High Himalayan slab (Main Central Thrust active 21-19 Ma) was synchronous with N-S (in Zanskar NE-SW) extension along the top of the slab (South Tibet Detachment Zone). Kyanite and sillimanite gneisses in the footwall formed at pressure of 8-10 kbars and depths of burial of 28-35 km, 30- 21 Ma ago, whereas anchimetamorphic sediments along the hanging wall have never been buried below ca. 5-6 km. Peak temperatures may have reached 750 on the prograde part of the P-T path. Thermobarometers can be used to constrain depths of burial assuming a continental geothermal gradient of 28-30 °C/km and a lithostatic gradient of around 3.5-3.7 km/kbar (or 0.285 kbars/km). Timing of peak metamorphism cannot yet be constrained accurately. However, we can infer cooling histories derived from thermochronometers using radiogenic isotopic systems, and thereby exhumation rates. This paper reviews all the reliable geochronological data and infers cooling histories for the Himalayan zone in Zanskar, Garhwal, and Nepal. Exhumation rates have been far greater in the High Himalayan Zone (1.4-2.1 mm/year) and southern Karakoram (1.2-1.6 mm/year) than along the zone of collision (Indus suture) or along the north Indian plate margin. The High Himalayan leucogranites span 26-14 Ma in the central Himalaya, and anatexis occurred at 21-19 Ma in Zanskar, approximately 30 Ma after the collision. The cooling histories show that significant crustal thickening, widespread metamorphism, erosion and exhumation (and therefore, possibly significant topographic elevation) occurred during the early Miocene along the central and eastern Himalaya, before the strengthening of the Indian monsoon at ca. 8 Ma, before the major change in climate and vegetation, and before the onset of E-W extension on the Tibetan plateau. Exhumation, therefore, was primarily controlled by active thrusts and normal faults, not by external factors such as climate change.

scholarly journals Erosion in southern Tibet shut down at ∼10 Ma due to enhanced rock uplift within the Himalaya

2015 ◽  
Vol 112 (39) ◽  
pp. 12030-12035 ◽  
Author(s):  
Marissa M. Tremblay ◽  
Matthew Fox ◽  
Jennifer L. Schmidt ◽  
Alka Tripathy-Lang ◽  
Matthew M. Wielicki ◽  
...  
Keyword(s):  
Large Scale ◽  
Southern Tibet ◽  
Conceptual Tool ◽  
Exhumation Rate ◽  
Lhasa Terrane ◽  
Drainage Networks ◽  
Southward Shift ◽  
Southern Tibetan Plateau ◽  
The Himalaya ◽  
Lithospheric Dynamics

Exhumation of the southern Tibetan plateau margin reflects interplay between surface and lithospheric dynamics within the Himalaya–Tibet orogen. We report thermochronometric data from a 1.2-km elevation transect within granitoids of the eastern Lhasa terrane, southern Tibet, which indicate rapid exhumation exceeding 1 km/Ma from 17–16 to 12–11 Ma followed by very slow exhumation to the present. We hypothesize that these changes in exhumation occurred in response to changes in the loci and rate of rock uplift and the resulting southward shift of the main topographic and drainage divides from within the Lhasa terrane to their current positions within the Himalaya. At ∼17 Ma, steep erosive drainage networks would have flowed across the Himalaya and greater amounts of moisture would have advected into the Lhasa terrane to drive large-scale erosional exhumation. As convergence thickened and widened the Himalaya, the orographic barrier to precipitation in southern Tibet terrane would have strengthened. Previously documented midcrustal duplexing around 10 Ma generated a zone of high rock uplift within the Himalaya. We use numerical simulations as a conceptual tool to highlight how a zone of high rock uplift could have defeated transverse drainage networks, resulting in substantial drainage reorganization. When combined with a strengthening orographic barrier to precipitation, this drainage reorganization would have driven the sharp reduction in exhumation rate we observe in southern Tibet.

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