Tsunami Induced Transportation of The Coastal Marine Sediments to Distant Onshore Regions: Some Indications from Foraminiferal and Microbenthic Studies of new Wandoor Region (Andaman & Nicobar)

Khare N., Chaturvedi S.K.1 and Ingole B.2*

The foraminiferal and microbenthos studies were carried out on samples collected from onshore soils/sediments from cultivated fields. The presence of exclusive marine organisms namely foraminifera in the soil of cultivated fields at distant onshore regions near New Wandoor (Andaman and Nicobar) suggested the areal extent of marine transgression due to tsunami waves on December 26, 2004. There is a need to investigate coastal marine sediments with multi-disciplinary approach to understand impact of the said tsunami on the onshore regions.

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A Proactive Approach to Geohazards Management in Developing Countries Using Geoinformatics: the Caribbean Experience

Baban Serwan M. J.

Geohazards in developing countries cause loss of life, social disruption, serious damage to the economy and environment. In general, current management of Geohazards in these countries tends to be reactive and is focused on cleaning-up operations, repairing infrastructure and providing comfort to affected population post-event. Evidently, there is a need for a proactive approach that enables managers to plan and to assist with informed decision-making. However, this process will face several challenges including the lack of an effective and reliable information base. This paper advances a Geoinformatics founded holistic method as the basis for developing a proactive approach for Geohazards management in developing countries. Successful examples based on partially implementing this approach in Trinidad and Tobago are provided.

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Suggestion of Monthly Water Supply Reliability Indexes for the Drought Disaster Prevention in South Korea

Park Ki-Bum 1, Kim Sungwon 2* and Lee Yeonghwa3

Water supply reliability indexes (WSRI) are estimated for assessment of water supply capacity in the downstream for parallel reservoir system in Nakdong River, South Korea, using allocation rule (AR) according to the water supply capacity of each reservoir and the characteristic of parallel reservoir system. The result of the analyzing parallel reservoir system for Andong and Imha reservoir in Nakdong River does not include evidences available enough to decide whether the results of water supply analysis are excellent in the current reliability evaluation or not. However, AR (C) shows a good result in the water supply capacity for each reservoir based on the connected operation system and the total water supply capacity at the control point of downstream by the average water supply capacity and possible range of water supply capacity suggested by this study. The average water supply capacity is analyzed by the reliability of monthly average water supply capacity. Furthermore, the possible range of water supply capacity is estimated by the standard deviation when water deficit occurs. Therefore, AR (C) is useful to establish and estimate the planning water supply capacity according to the monthly water supply condition and the possible range of water supply capacity when the water supply capacity deficit occurs in South Korea.

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Probabilistic Evaluation of Seismic Risk in the Western part of North-East India and Adjoining Regions

Khound A.P., Sarmah S.K.1 and Das P. K. 2*

The Western part of N.E. India and its adjoining regions have been demarcated as seismically very active region of the world. The region was the seat of many destructive earthquakes in the past. Earthquakes of magnitude more than 8.0 on the Richter scale occurred in this region in 1897 (The great Shillong Earthquake), 1934 (The Bihar-Nepal Earthquake) and 1950 (The great Assam Earthquake). These earthquakes were responsible for great damage and loss of life. A large number of glo­bal and regional studies on the seismicity, geology, tectonics and seismic risk of Northeast India have been found to be available in reviews of literature. But most of the studies do not include meizoseismal area of Bihar-Nepal earthquake of 1934. In this study probabilistic seismic risk of the area lies between latitude 22°N to 30°N and longitudes 85°E to 93°E has been evaluated. Gumbel’s extreme value distributions have been utili­zed to determine the return periods as well as the most probable largest earthquake that may occur in the region under study. The region is characterised by net-work of lineament fabric which constitute the weak zones for seismic activities. As the tectonic structure of the region is very complex, the entire study region has been divided into three tectonic blocks. The Gumbel’s theory has also been applied to individual tectonic blocks. The theory of Gumbel’s extreme value has been applied to the largest annual earthquakes occurring between 1930 to 1993 within the study area, using type I, type III and tanh-fit case of Howell. Seismic risk in terms of the mean return periods for earthquakes of various magnitudes and hence the probability of occurrences have been estimated. For the region as a whole, an earthquake of magnitude not less than (mb) 7.5 can be expected in every 30 years by type I, 117 years by type III distribution and 92 years by tanh-fit case. Applying type I distribution, for a return period of 50 years, the most probable largest magnitude has been found to be mb = 7.9. Type III and tanh-fit case for a period of 50 years yield magnitudes (mb) 7.3 and 7.4 respectively as the most probable largest magnitude. Moreover, considering individual tectonic blocks the return period of an earthquake of magnitude mb = 7.0 has been found to be less for block I than that for other two blocks i.e. seismic risk of Shillong plateau is more than that of the Eastern Himalaya and the Eastern part of Central Himalaya. It follows from the results that type III distribution having lowest value of r.m.s. error of fit, seems to provide the best fit to the observational data.

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Simulation of Short Range Hermitzed Atmospheric Dispersion in low-wind Convective Conditions

Essa Khaled S. M. * and El-Otaify Maha S.

An analytical solution is obtained before using model hermitzed atmospheric dispersion in low winds4 which is used to simulate diffusion tests during winter in weakly convective conditions at Indian Institute of Technology (IIT) Delhi. The turbulent parameterization depended upon friction velocity has been tested to estimate diffusion experiment. The model estimations have improved and compare well with observations and simple Gaussian model.

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Stability Mapping and Landslide Recognition in Zagros Mountain South West Iran: A Case Study

Pirasteh Saied1*, Pradhan Biswajeet 2 and Mahmoodzadeh Amir3

The present study area is belonging to the Zagros Structural Belt (ZSB) south west Iran. It is part of Alpine Himalayan origin supposed to be newly active zone. Information was generated through remotely sensed data and GIS techniques. Digital elevation model (DEM), stability and saturation zones, drainage basin network, geological map were extracted and analyzed in conjunction with several field visits to deduce the recognize landslide. Buffering techniques were applied to distance proximity of hazard on infrastructure caused by landslide. Buffering techniques indicate that there will not be any loss of infrastructure in the study area while railway line passes this area the study reveals the influence of rock type for the development of the drainage patterns. This study indicates that the development of the landslides in the study area is not affected by moisture but it is influenced by topography, development of lineaments and chemical reaction phenomena. This study also reveals the applications of remote sensing and GIS for the engineering geology in the ZSB while the railway transportation line of Tehran-Andimashk passes the area with many tunnels and bridges.

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Studies on Changes in the Environmental Features of the Mulki Estuary in relation to Tides

Viajayakumar S., Nagaraju D*., Madesh P1. and Manjunath S2

Some of the physico-chemical parameters like tem­perature, pH, dissolved oxygen, ammonia-nitro­g­en, nitrite-nitrogen, nitrate-nitrogen, phosphate -ph­­­o­­sp­­horus and silicate-silicon were investigated at the Mulki estuary under under high and low tide condi­ti­o­ns during monsoon, post and pre-monsoon periods. pH and salinity increased during high tides while dis­s­ol­v­e­d oxygen trend is independent of tidal effects. Amm­o­n­i­a, nitrite, nitrate, phosphate and silicate incr­­e­­a­sed du­ring low tide. Higher values of all the nu­tri­en­ts du­r­­i­ng monsoon season suggest the fres­h­wa­t­er infl­ux as a vital source of nutrients for the estuary.

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