Modeling catchment sediment yield: a genetic programming approach     

Vaibhav Garg 《Natural Hazards》2014,70(1):39-50

Hydrologic processes are complex, non-linear, and distributed within a watershed both spatially and temporally. One such complex pervasive process is soil erosion. This problem is usually approached directly by considering the sediment yield. Most of the hydrologic models developed and used earlier in sediment yield modeling were lumped and had no provision for including spatial and temporal variability of the terrain and climate attributes. This study investigates the suitability of a recent evolutionary technique, genetic programming (GP), in estimating sediment yield considering various meteorological and geographic features of a basin. The Arno River basin in Italy, which is prone to frequent floods, has been chosen as case study to demonstrate the GP approach. The results of the present study show that GP can efficiently capture the trend of sediment yield, even with a small set of data. The major advantage of the GP analysis is that it generates simple parsimonious expression offering some possible interpretations to the underlying process.  相似文献   

Source parameters estimation of 2003 Bam earthquake Mw 6.5 using empirical Green’s function method,based on an evolutionary approach     

Ahmad Nicknam  Reza Abbasnia  Yasser Eslamian  Mohsen Bozorgnasab  Ehsan Adeli Mosabbeb 《Journal of Earth System Science》2010,119(3):383-396

We determine the source parameters for 2003 (Mw 6.5) Bam, Iran, earthquake using an empirical Green’s function summation approach to model ground motions recorded by two strong motion stations at approximately 45 km epicentral distance. We introduce a genetic algorithm technique to optimize the fit to observed elastic response spectra. The proposed genetic algorithm technique allows us to explore the sensitivity of the results to multiple source parameters, including hypocenter location, focal mechanism (Strike and Dip), P-wave velocity in depth, fault dimension and rupture and healing velocities.  相似文献   

Paleochannel and paleohydrology of a Middle Siwalik (Pliocene) fluvial system,northern India   总被引：2，自引：0，他引：2  

Z A KHAN  R C TEWARI 《Journal of Earth System Science》2011,120(3):531-543

Late Cenozoic fresh water molasses sediments (+6000 m thick) deposited all along the length of the Himalayan fore deep, form the Siwalik Supergroup. This paper reports the results of the paleodrainage and paleohydrology of the Middle Siwalik sub-group of rocks, deposited in non-marine basins adjacent to a rising mountain chain during Pliocene. Well-exposed sections of these rocks have provided adequate paleodrainage data for the reconstruction of paleochannel morphology and paleohydrological attributes of the Pliocene fluvial system.  相似文献   

Origin and emplacement of the Higher Himalayan Leucogranite in the eastern Himalaya: Constraints from geochemistry and mineral chemistry     

R. K. Bikramaditya Singh 《Journal of the Geological Society of India》2013,81(6):791-803

The Higher Himalayan Leucogranites (HHLG) intruded into the high grade rocks of the Higher Himalayan Crystallines (HHC) in western Arunachal Pradesh, eastern Himalaya, yield distinctive field data, petrography, geochemical and mineral chemistry data. The HHLG mostly occur as sill like bodies of limited thickness and lateral extent within the HHC. The Arunachal HHLG are characterized by the presence of two micas; normative corundum; high contents of SiO₂ (67–78 wt.%), Al₂O₃ (13–18 wt.%), A/CNK (0.98–1.44) and Rb (154–412 ppm); low contents of CaO (0.33–1.91 wt.%) and Sr (19–171 ppm), and a high ratio of FeO_(tot)/MgO in biotite (2.54–4.82). These distinctive features, along with their strong depletion in high field strength elements (HFSE), suggest their affinity to peraluminous S-type granite generated by the partial melting of crustal material. Since the HHLG associated with high grade rocks of HHC and lack of basaltic magmatism, strongly suggests that the high grade rocks of HHC might represent the melt source and HHLG are product of pure crustal melt without any contamination of mantle material. Geothermobarometric estimations and mineral assemblages of the HHC metapelites confirm that the HHLG were probably generated in the middle crust (～20 km) and the produced melts intruded the HHC in the form of sills/dykes.  相似文献   

Ichnology of the Early Cambrian Tal Group, Mussoorie Syncline, Lesser Himalaya, India     

MEERA TIWARI  S K PARCHA  RAJITA SHUKLA  HARSHITA JOSHI 《Journal of Earth System Science》2013,122(6):1467-1475

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Landslide Hazard in the Nainital township,Kumaun Himalaya,India: the case of September 2014 Balia Nala landslide     

Vikram Gupta  Rajinder K. Bhasin  Amir M. Kaynia  Ruchika Sharma Tandon  B. Venkateshwarlu 《Natural Hazards》2016,80(2):863-877

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Modeling the strong ground motion and rupture characteristics of the March 31, 2006, Darb-e-Astane earthquake,Iran, using a hybrid of near-field SH-wave and empirical Green’s function method   总被引：1，自引：0，他引：1  

H. Hamzehloo  H. Rahimi  I. Sarkar  M. Mahood  H. Mirzaei Alavijeh  E. Farzanegan 《Journal of Seismology》2010,14(2):169-195

We analyze the strong motion accelerograms of the moderate (M _w = 6.1), March 31, 2006, Darb-e-Astane earthquake of western Iran and also those of one of its prominently recorded, large (M _w = 5.1) foreshock and (M _w = 4.9) aftershock. (1) Using derived SH-wave spectral data, we first objectively estimate the parameters W _o\mathit{\Omega} _{\rm o} (long period spectral level), f _c (corner frequency) and Q(f) (frequency dependent, average shear wave quality factor), appropriate for the best-fit Brune ω ^− 2 spectrum of each of these three events. We then perform a non-linear least square analysis of the SH-wave spectral data to provide approximate near-field estimates of the strike, dip, and rake of the causative faults and also the seismic moment, moment magnitude, source size, and average stress drop of these three events. (2) In the next step, we use these approximate values and an empirical Green’s function approach, in an iterative manner, to optimally model the strong ground motion and rupture characteristics of the main event in terms of peak ground acceleration/velocity/displacement and duration of ground shaking and thereby provide improved, more reliable estimates of the causative fault parameters of the main event and its asperities. Our near-field estimates for both the main moderate event and the two smaller events are in good conformity with the corresponding far-field estimates reported by other studies.  相似文献   

Litho-tectonic sequence and their regional correlation along the Lohit and Dibang valleys,eastern Arunachal Pradesh     

D. K. Misra 《Journal of the Geological Society of India》2009,73(2):213-219

Geological mapping between Lohit and Dibang valleys of eastern Arunachal Pradesh reveals the existence of five thrust bound tectonostratigraphic units. In ascending structural order from SW to NE these are: (1) Sewak Group, (2) Lalpani Group, (3) Mayodiya Group, (4) Tidding Formation and (5) Lohit plutonic complex. This differs from previous mapping, because the three tectonostratigraphic units (Sewak, Lalpani and Mayodiya) were grouped under a single unit, referred as the Mishmi crystallines. The low-grade metamorphics of the Sewak Group occur at two different tectonic levels, one as persistent belt in the foothills and the other in the tectonic window beneath the high-grade metamorphics of the Mayodiya thrust sheet in the Higher Himalaya. The Tidding suture is the southeastern extension of the Indus-Tsangpo suture zone.  相似文献   

Micro faunal assemblages in the Ordovician – Silurian successions from the Pin Valley of Tethys Himalaya, India     

S. K. PARCHA  Shivani PANDEY 《地球学报》2009,30(Z1):49-49

The Spiti basin together with the Zanskar basin forms the largest basin among the Tethyan Himalayan successions and forms one of the best-developed sec-tions in the Tethyan Tibetan belt. The basin is one of the classical areas, which depicts a continuous fos-siliferous Palaeozoic - Mesozoic successions. The present studies are focused on the Ordovician and Si-lurian successions of the Pin valley of the Spiti basin. Pin valley exposes richly fossiliferous lithological successions from Neoproterozoic to Cretaceous; therefore, it is an ideal section for the detail paleobi-ological and geological studies.  相似文献   

Reconstruction of Last Glacial to early Holocene monsoon variability from relict lake sediments of the Higher Central Himalaya,Uttrakhand, India     

N. Juyal  R.K. Pant  N. Basavaiah  R. Bhushan  M. Jain  N.K. Saini  M.G. Yadava  A.K. Singhvi 《Journal of Asian Earth Sciences》2009,34(3):437-449

Proglacial lake sediments at Goting in the Higher Central Himalaya were analyzed to reconstruct the summer monsoon variability during the Last Glacial to early Holocene. Sedimentary structures, high resolution mineral magnetic and geochemical data suggest that the lacustrine environment experienced fluctuating monsoonal conditions. Optically stimulated luminescence (OSL) dating indicates that the lake sedimentation occurred before 25 ka and continued after 13 ka. During this period, Goting basin witnessed moderate to strengthened monsoon conditions around 25 ka, 23.5 ka–22.5 ka, 22 ka–18 ka, 17 ka–16.5 ka and after14.5–13 ka. The Last Glacial phase ended with the deposition of outwash gravel dated at ～11 ka indicating glacial retreat and the onset of Holocene condition. Additionally, centennial scale fluctuations between 16.5 ka and 12.7 ka in the magnetic and geochemical data are seen.A close correspondence at the millennial scale between our data and that of continental and marine records from the Indian sub-continent suggests that Goting basin responded to periods of strengthened monsoon during the Last Glacial to early Holocene. We attribute the millennial scale monsoon variability to climatic instability in higher northern latitudes. However, centennial scale abrupt changes are attributed to the result of albedo changes on the Himalaya and Tibetan plateau.  相似文献