Assessment of short term shoreline changes along Tuticorin, Southeast coast of India using Geospatial Techniques

Parthasarathy Anitha and Natesan Usha

Shoreline is the boundary between land and sea which is dynamic in nature and provides economic and social security to the coastal livelihoods. Tuticorin located along the Gulf of Mannar, southeast coast of India with high ecological diversity faces multi-threats due to anthropogenic interventions as a result of urbanization, industrialization, sand and coral mining etc. In this study, shoreline changes was investigated from multi-date satellite data along Tuticorin coast using remote sensing data and geographical information technique coupled with Digital Shoreline Analysis System Software (DSAS) based on End Point Rate (EPR) and Linear Regression Rate-of-change (LRR). Maximum shoreline change rates of -12.04 (erosion) and 8.36 (accretion) m/yr are observed based on LRR method. Out of 100 km coastal stretch, 31.7 km of the coastal stretch at Vembar, Periyasamypuram, Kalaignanapuram and Punnakayal villages fall under very high risk category with erosion rates of more than -2.0 m/yr. This study provides a synoptic view to erosion and accretion rates in the study area and the degree of threat to the coastline.

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A Method for Comprehensive Prediction of Unfavorable Geological Conditions in Tunnels

Tianbin Li and Lubo Meng

A principle of comprehensive prediction “taking the geological investigation analysis as the core, integrating the geological investigation with geophysical exploration, surveying both the inside and outside conditions of the tunnel, combining long distance prediction methods with the short distance ones and verifying appropriateness of various geophysical methods” is adopted for advanced forecast of geology in tunnels. The comprehensive workflows and appraising classification system of unfavorable geology such as fault, breaking rock mass, vast groundwater, solution cavity, soft rock mass in tunnels are developed. Through extracting geological and geophysical parameters, a comprehensive prediction model of geological problems is constructed by fuzzy neural network. The comprehensive prediction system was used in the Tongluoshan cast tunnel and the accuracy of the prediction was estimated at 80%.

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QVariability in the local current pattern due to meso-scale eddies – A case study of the southwest coast of India

Hareesh Kumar P.V.

The observed variability of subsurface currents at a location (9o45’N, 75o45’E) in the southeastern Arabian Sea (SEAS) was described and explained utilizing short time series measurements from a shallow water mooring and geostrophic currents estimated from satellite altimetry. The data provided the direct observation of the variability of the West India Coastal Current (WICC) and its possible link with wind and meso-scale eddies. In the surface layers, northward WICC is observed during the monsoon season, driven by the cyclonic eddy that prevails in the SEAS. During winter, the WICC is northeastward that flows against the local winds. At the subsurface levels, northward flowing undercurrents are observed during the pre-monsoon and summer monsoon seasons which are typical for the eastern boundary coastal upwelling. In the region of northward flowing currents, the watermass characteristics are distinctly different during the summer monsoon and winter.

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The application of seismiostratigraphy in dynamic analysis of compact alluvial layers

Mostafa Yousefi Rad and Ebrahim Robatmili

The aim of this study was the seismic study of alluvial sediments units from an engineering site point of view. In order to investigate the effect of alluvial unit thickness on the seismic response, the desired site was modeled in 2800 regulation to determine the distribution of stress of these layers above the rocky bed and below a particular site and also to determine the effect of soil layer of bedrock on the ground surface motions. The results showed that with increase in the thickness due to the retreat of main system frequency from dominant frequency of earthquake (6.5), an increase in soil layer thickness decreases the response intensity.

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The Operation Management and Disaster Reduction Application Potential Analysis for HJ-1-C

Wang Lei and Zhang Wei

Being the third satellite of Environment and Disaster Monitoring and Forecasting, Small Satellite Constellation (shorted as HJ-1) HJ-1-C was launched successfully on Nov 19, 2012. It is the first civil Synthetic Aperture Radar (SAR) satellite in China and is also the only S-band SAR satellite on orbital in the world at present. Based on the interpreting and analyzing characteristic information about disaster-inducing factors (such as water body, ice slush, sea ice etc.) and hazard-affected body (such as building, road, bridge etc.) with HJ-1-C data during the orbital test period, this paper analyses potential of S-band SAR satellite image data in the disaster monitoring and assessment and proposes disaster reduction application benefit of S-band SAR satellite. The successful launch of HJ-1-C has filled the S-band blank of nowadays SAR satellite in the world and will offer brand new data resource guarantee to disaster reduction application by using remote sensing technique and will provide important experience and basis towards program and demonstration of future remote sensing satellite in China.

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Comparison of wave prediction methods in Asaluye port

Shabanlou S. and Ahmadvnd H.

Waves caused by wind are one of the most important phenomena in marine environments that are effective in the coastal and offshore processes. This purpose of this study is to evaluate the accuracy of experimental and spectral methods in predicting of waves caused by wind characteristics in Asaluye. Thus, the wind data from the Ports and Maritime Organization in 2002 was collected. Then empirical methods including SMB, SPM, CEM and JONSWAP were used and wave characteristic for wind durations of 6, 9 and 12 hours were calculated. Predicted wave heights and wave periods compared with data collected and experimental methods errors were determined. According to research conducted, JONSWAP method among experimental methods in duration of 6 hours is the most appropriate method to determine the wave profile in Asalouye port. For more complete evaluation of wave prediction methods, Wave height based on the measured data compared with significant wave height was calculated by each of Bretschneider, Mitsuyasu, Pierson-Moskowitz, JONSWAP, ISSC spectrum. In this study it was found that the Bretschneider, Mitsuyasu and Pierson-Moskowitz spectrum show lowest error in the calculation of this parameter. To better match the measured spectra, their coefficients were corrected and height value was calculated using each spectrum. Then, using corrected and uncorrected spectra, directional spectra of the region were plotted.

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Correlation of Strength and Stability of Large Glacial Tills in Dry-warm Valley Area of Minjiang River with respect to Saturation

Feng Wen-Kai, Zeng Lin-Jie and Wu Gang

Progressive deformation of large glacial tills in areas of dry-warm valley in the upper reaches of the Minjiang River has brought significant security risks to roads and town construction along the river. It showed by studies that the impact of rainfall on this type of glacial tills is very significant. This study selected representative deposit samples from Xiaoqi village and investigated the strength variation characteristics of such glacial tills under different saturations. It is found that as the saturation increased, the glacial tills' cohesion c, internal friction angle φ and the shear strength at potential sliding interface (bedrock-cover interface) decreased exponentially. The relational trend curves were consistent with the test results and the function of saturation and the three factors. In addition, the calculation of stability showed that when glacial tills had optimum moisture content, the slope would be in a less stable state, with risks of deformation and destruction. It is the recommended value to set the monitoring and warning thresholds based on this information.

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Establishing the sequence-stratigraphic framework of a lacustrine basin during its withering period using multiple methods and technologies: A case study of the Neocene of the Huanghekou Sag, Bohai Bay Basin, China

Liu Hao

The Huanghekou Sag is located in the southeastern part of the Bohai Bay Basin. The Neocene was a withering period and the depressional lacustrine basin was characterised by 1) tectonic stability and slow subsidence, 2) a large area of shallow water and gentle topography, 3) stable provenance and weak separation and 4) a well developed rift and strong fragmentation. Therefore, it is difficult to identify and subdivide sequences using the traditional well-seismic data combination method. The establishment and subdivision of the sequence stratigraphy of the withering period of a continental lacustrine basin was accomplished using a multi-method approach and appropriate technology based on practical aspects of the geological setting and on current data for the Miocene of Huanghekou Sag, Bohai Sea. Specifically, the method is based on cycle analyses (climate cycle, drilling well and logging cycle and seismic cycle); on the examination of the unconformities identified from seismic and drilling wells and logging data; on considerations of the drilling well-seismic combination through the plane network closure of the results of interpretation of the sequence surface from seismic, drilling well and logging data and on a confirmation of the rationality of the sequence subdivision. These analyses yielded a comprehensive subdivision of the sequence stratigraphy and served to establish this stratigraphy. The results of the identification and subdivision of the sequence indicate that climate cycles are apparent, that the drilling well and logging cycles are clear and that the multi-stage seismic reflection cycles are well developed. In the Miocene of the Huanghekou Sag, 4 third-order sequences and 8 systems tracts were subdivided and combined with the identification of sequence boundaries from drilling wells, logging and seismic data and the internal constitution (systems tract) and developing scale. The sequence is characterised by a large-area lacustrine basin and gentle topography manifested in the distribution of thickness in the sequence and in the systems tract. The local low sub-sag and ditch valley formed in the early depositional period may represent the primary area of development of the sandbody occurring in the late sequence. The biases in the distribution of topography in the Miocene fault indicate that the macro-distribution of sandbodies in different periods is consistent with the characteristics of the faults and that the exploration of shallow systems has a substantial potential.

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Sediment transport patterns, hydrodynamic conditions and clay minerals distribution of sediments from Coleroon River Estuary, East Coast of India

Venkatramanan S., Chung S.Y. and Ramkumar T.

The present study was carried out in order to study the textural characteristics of sediments and their seasonal changes along with the Coleroon estuary. Sediment samples were collected at different stations in monsoon, postmonsoon, summer and premonsoon seasons from 2009 to 2010. Spatial variations in grain-size parameters (i.e. grain-size trends) contain information on sediment transport patterns. Analytical procedures have been proposed using the grain-size trends to determine sediment transport pathways. Spatial distribution of sediments clearly indicated more finer particles deposited at mid estuarine region compared to at mouth and freshwater region. Hydrodynamic condition of Coleroon estuarine sediments indicates moderate to high energy condition. The grain size trend analysis indicates the estuarine sediments belong to type-1 trend F, B (finer, better sorted more negative skewed). Clay mineral studies exhibit the observed order of abundance minerals are illite followed by the kaolinite+chlorite, montmorillonite and gibssite. The higher percentage of clay minerals was present at estuary and mouth regions when compared to the freshwater region.

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Earthquake Risk Perception and Communication: A Review of Empirical Research

Jaime Santos-Reyes, Tatiana Gouzeva and Galdino Santos-Reyes

A review of the state of the art has been conducted on earthquake risk perception (RP) and risk communication (RC). The review comprises 29 empirically based peer-reviewed papers on earthquake RP and RC from the electronic online databases 'Scopus' and 'Web of Science'. The results show that there is a need to a theoretical sound approach to the statistical analyses and the need to be more explicit when presenting the results. A longitudinal study may be a way forward. There is a need of research on RC. Some discussion is presented on methodological issues and finally, some future research direction is given.

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