Deformation of textural characteristics and sedimentology along micro-tidal estuarine beaches

1432-1444Deformation in the textural characteristics of three selected beaches (Pavinkurve, Kundapura and Padukare) along Karnataka shoreline, west coast of India was examined. Study showed the beaches are significantly composed of unimodal to bimodal, fine to medium sand, moderately well sorted to moderately sorted, positive to negative skewed, and platykurtic to leptokurtic sediments. Spatio-temporal variation of mean grain size showed significant influence of breaking waves on beach sediments whereas sorting characteristics exhibited the impact of alongshore current on the intertidal sedimentary environment. Also very fine sands at gentle beach slope and very coarse sands at steeper slope exhibits the role of beach morphology on foreshore surface grains. The slow process of sediment removal/accumulation reveals a marginal variation in skewness and kurtosis characteristic and also exhibits a poor correlation in textural characteristics

Freak waves off Ratnagiri, west coast of India

1339-1342Freak <span style="font-size:11.0pt;mso-fareast-font-family: " times="" new="" roman";mso-bidi-font-family:mangal;background:white;mso-ansi-language:="" en-in;mso-fareast-language:en-us;mso-bidi-language:hi;font-style:normal"="">waves are relatively large and spontaneous ocean surface gravity waves whose heights are larger than the expected maximum wave height for a given sea state. Wave data collected off Ratnagiri, along the west coast of India during <span style="font-size:11.0pt; mso-fareast-font-family:" times="" new="" roman";background:white;mso-ansi-language:="" en-in;mso-fareast-language:en-us;mso-bidi-language:hi"="">1 January to 31 December 2011 using directional wave rider buoy at 13 m water depth is used to study the freak waves. Abnormality Index (AI), the ratio between maximum wave height and significant wave height, is used to identify and study the variation of the freak wave events off Ratnagiri. From the half hourly wave data covering one year period, 89 freak wave events are observed. The statistics built on these selected events suggests that maximum freak events (29 events) are during the rough SW monsoon and 20 events during the calm pre-monsoon season. Highest freak wave (wave height=6.9 m) is observed in July 2011. The Abnormality Index varied from 2 to 2.5 during the study period. Daily variations in number of freak wave events are associated with the interaction between sea-breeze generated random wind sea and swells propagating towards the study area.</span