CLASSIFICATION AND CHARACTERISTIC OF CORAL BEACHES BASED ON SEDIMENT PROPERITIES

Abstract

 Field surveys were carried out at thirty-four beaches at Okinawa. Sediment samples were collected near the shoreline and beach face slopes were measured from the shoreline to the run up height. The sediment constituents were identified and counted visually or under a microscope. The properties of sediment sample such as grain size, roundness and color were analyzed by images of sand particles.

 Data shows that coral grains are the dominants constitutes, followed by foraminifera, shellfishes, minerals and sea ruinous. The coral beaches can be divided into 6 groups by the concept of entropy with the percent of sediment constitutes. The distance between the coral leaf and the shoreline was correlated with the percent of sediment constitutes. The magnitude of the exponent on simple power-low relationships between grain size and beach face slope at coral beaches is larger than that of sandy beaches. The sediment constitutes could be identified and counted by roundness, brightness and saturation of sediments.