I determined the source parameters of 53 moderate-sized earthquakes in the region of the Eastern Himalayan Syntaxis through the joint inversion of regional and teleseismic distance long-period body waves. The average rates of deformation are determined by summing the moment tensors from both recent and historic earthquakes. Strike-slip movement on the Sagaing fault terminates in the north (just south of the syntaxis), where thrusting (northeast convergence) and crustal thickening are predominant. Slip vectors for thrust mechanisms in the Eastern Himalaya in general are not orthogonal to the Himalayan mountain front but show an oblique component of slip. A combination of thrust and strike-slip faulting (Molnar and Deng, 1984) for the great 1950 Assam earthquake is consistent with the rates of underthrusting in the entire Himalaya and the rate of spreading in Tibet (assuming that a 1950-type earthquake recurs every 400 years). An estimated 4-21 mm/yr of right-lateral motion between southeast Asia and the Burma subplate is absorbed within the zone of distributed shear between the Sagaing and Red River faults. A component of westward motion (3-7 mm/yr) of the western boundary of the distributed shear zone may cause some of the late Cenozoic compression and folding in the northern Indoburman Ranges. Distributed shear and clockwise rotation of blocks is also occurring in Yunnan north of the Red River Fault. The inversion of 130 regional distancewaveforms for average crustal thickness and upper mantle Pn velocity indicates an increase in Pn velocity, coincident with increase in crustal thickness, of about 0.20 km/s beneath the Tibetan Plateau. Impulsive Pn arrivals from paths that cross the Tibetan Plateau can be modeled with a positive upper mantle velocity gradient, indicating an upper mantle lid approximately 100-km-thick beneath southern Tibet. This "shield-like" structure supports a model in which Indian continental lithosphere has underthrust Tibet. The crustal shortening within Tibet 8 mm/yr is thus viewed as an upper crustal phenomenon in which the faults do not penetrate the deep crust or upper Mantle. The forces generated by the thick crust in Tibet may partly cause the strike-slip faulting and east-west convergence in Sichuan and the movement of upper crustal blocks in Yunnan.

No description available.

Extensive studies have been undertaking in exploring the tectonic evolution of the Himalayan Orogen. Various tectonic models were developed to explain and constraint spatially and temporally critical events including the collision of Indian Plate with the Eurasia Plate, crustal thickening in association with the indentation, crustal spreading of the Tibetan Plateau. Recent study by King et al., 2011 identified two distinct leucogranite suites which were formed by contrasting tectonic actions at Sakya. They are Equigranular Anastomosing Leucogranite (AEG) formed under prograde fluidpresent condition while the Discrete Porphyritic Pluton Leucogranite (DPP) formed with retro-grade fluid-absent environment. Based on the characteristics of AEG and DPP, this study started with the acquisition of geochemistry data of rock samples collected for researches at various locations of the Himalaya Orogen. The two leucogranite suites were characterized through the study of their geochemistry comprised major elements, trace elements and rare earth elements models. Results of the studies concluded the existence of AEGs and DPPs distributed over the eastern area of the Himalaya Orogen beyond longitude 85 degree East. DPPs are also found at the far West location of the orogen. AEGs are typically formed from around 38Ma to 23Ma, while DPPs are of young age from 23Ma to 15Ma. Based on the observation of missing, or paucity in data for AEG and DPPs available to the west of longitude 85 degree East, it is hypothesized that recent collision of the Arabia plate to the Iran Domain inhibited the northward indentation movement of the Indian plate that not only caused the anticlockwise rotation of the Indian plate but also decreased the rate of tectonic movement of the Indian plate in the West relative to Eurasia plate. The slow rate of tectonic movement may result in insufficient thickening/energy developed within the crustal layer to cause any melting. Further studies to examine and development of the hypothesis is recommended. / published_or_final_version / Applied Geosciences / Master / Master of Science

This thesis deals with the perception and representation of spirits and landscape among Tibetan Buddhist laity in Ladakh, Himalayan India. It contrasts the conventions of Tibetan textual description of places with stories told by Ladakhi Buddhist laity, with a focus on the role played by local spirits and deities. It argues that while textual representations employing the unified and symmetrical imagery of the maṇḍala – a schematic representation of the palace of a divinity – depict the landscape as it might be known to a transcendent observer, stories about places and the spirits associated with them (lhande in Ladakhi) point to an indeterminate, fragmented and culturally unbounded world that has yet to be integrated within any single system of knowledge. This world is pieced together from multiple sources and truth claims, and from the imperfections inherent in ordinary perception; but the inconsistencies and uncertainties involved in this are not usually apparent, and are only made manifest in illness, experiences of disorder and encounters with spirits at night. These persistent uncertainties can be overcome in ritual contexts, in acts of writing or through the invocation of the faculty of divine vision: the palatial image of the maṇḍala is used to counteract the presence of the night outside. This thesis draws attention to the often overlooked role played by the limitations of perception and knowledge in understandings of landscape, and is intended to partly bridge a disciplinary divide by reconstructing the invisible context within which textual representations are created and employed.

Satellite image interpretation, geologic mapping, and paleoseismic trenching are used to investigate the Trans-Yamuna active fault system in the northwestern Doon Valley of the Indian Himalayan foothills. This east-west fault system is subparallel to and crosses the Main Boundary thrust near the structural transition from the Nahan salient to the Dehra Dun reentrant. The Trans-Yamuna active fault system may terminate to the east at a lateral ramp of the Main Boundary thrust. A south-side-up, relatively linear fault trace with variable fault dips suggests that the fault system is high-angle reverse with a component of strike-slip. It is subdivided into the Sirmurital, Dhamaun, and Bharli faults, which probably connect at depth. The Dhamaun fault is exposed where it cuts the late Holocene upper Bhatrog terrace deposit of the Giri River. A paleoseismic investigation of the Sirmurital fault at another Giri River terrace did not expose the fault, but it suggests that late Holocene terrace deposits there may be folded into a syncline parallel to fault strike. The fold axis of the syncline continues into bedrock to the west. Earthquakes in 1905, 1803, or perhaps earlier may have been the source of folding of the fine-grained sediments within this terrace deposit. The Trans-Yamuna active fault system is a secondary hangingwall fault that may accommodate some strain release above the decollement during large-magnitude earthquakes. Strike-slip motion may be related to the lateral translation of the Karakoram fault block and east-west extension of the southern Tibet block as a result of oblique convergence between the Indian and Eurasian plates in the northwest Himalaya. / Graduation date: 1999

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 120-131).

Thesis--University of California, Berkeley. / Includes bibliographical references (leaves 315-323). Also issued in print.

Thesis--University of California, Berkeley. / Includes bibliographical references (leaves 315-323).

Data on erosion processes and other aspects of environmental change in the Himalaya are scarce and unreliable, and consequently policy decisions have been taken in a quantitative vacuum. Published estimates of denudation for large catchments in Nepal vary from 0.51 to 5.14 mm/yr, and indicate a dynamic geomorphological environment A review of the literature on erosion in Nepal revealed a consensus that: (1) mass wasting is the dominant hillslope process; (2) activity is seasonal, with virtually all failures occurring during the monsoon; (3) geological factors are the most important determinants of slope stability; (4) sediment delivery to channels is high; (5) little quantitative evidence exists to link landsliding to deforestation. Although few data exist, loss of forest cover does appear to be related to surface erosion and gullying, and a hypothesis linking the expansion of unmanaged, eroding areas to reduced nutrient subsidies from the forest is proposed. A reconnaissance survey of sediment production and transfer mechanisms in the 122 km² Phewa Valley in the Middle Mountains of Nepal identified a variety of mass movement processes. The commonest events were shallow translational failures on slopes of, typically, 36° to 45°, with volumes ≤1 x 10³ m³ and with recovery taking less than ten years. Larger slides occurred on slopes oversteepened by fluvial action. Flows developed in areas of weak rock and unfavourable structure, and were associated with groundwater discharge. Flow velocities accelerated during the monsoon. The highly fractured and deeply weathered zones around faults were the sites of "mass movement catchments", complex failures responsible for approximately 90% of all sediment production by mass wasting in the watershed. A first estimate of surface lowering by mass movement processes in the Phewa Valley is 2-3 mm/yr. Locally, surface erosion on overgrazed pasture may be 5-6 mm/yr. No data were available on soil losses from cultivated areas, and, similarly, losses due to shallow creep, gullying and solution remain unknown. The fluvial transport system in the valley bottom is unable to transport all the material with which it is supplied. Sediment yield to the lake was not calculated owing to insufficient data. Discharge estimates and intensity-duration-frequency analysis of rainfall records indicate that in Pokhara storms of 275 mm/day have a return period of approximately 10 years. The primary controls on mass movement processes in the Middle Himalaya of Nepal are geological and climatic, and therefore are not amenable to modification by man. However, surface erosion is a consequence of poor land management, and therefore can be controlled, given the right institutional environment / Forestry, Faculty of / Graduate

Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Microfiche copy available in Archives and Science. / Bibliography: leaves 51-56. / by Waris E.K. Warsi. / M.S.