Remote-sensing perspective and GPR subsurface perception on the growth of a recently emerged spit at Talashil coast, west coast of India

Abstract

The growth as well as the internal structure of the recently emerged Talashil spit along the west coast of India was studied using multidate satellite images coupled with ground-penetrating radar (GPR) information. Decadal changes (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013) in configuration, geomorphology and erosion and accretion pockets along the spit were traced and compared. A 170 m long subsurface profile across the spit from shoreline to river shore was generated using GPR. Historical satellite images from 1973 to 2013 illustrate a rapid transformation of a linear sand bar into a matured spit. The growth trend over the period 2003-2013 shows mainly accretion along the seashore and erosion along the river shore. Three dynamic hot spot locations were noticed where erosion and accretion were alternately dominating. The radar facies clearly distinguishes zones of fluvial, dune and inter-tidal dominance and substantiates the interpretation of the satellite images. This study indicates spit formation following build up and emergence of a submerged shoal due to fluvial sedimentation, after which an equilibrium between erosion and accumulation was reached. The data indicate that the growth of the spit has reached its mature stage and only lateral oscillation of the spit is likely in the future unless sizable disturbances caused by either tectonic or anthropogenic processes influence this region. IntroductionRemote sensing of the environment provides multitemporal information on periodical changes in land cover and landform caused by the dynamic nature of the land-surface processes. This type of change-detection study through time-series images of a landform/ land cover factually reveals its various evolutionary stages in the past years and subsequently provides better scope to predicate its future growth trend. In this context, the multitemporal satellite images and aerial photographs are being widely used for changedetection mapping to study seasonal dynamics of land surfaces in order to assess and understand land-surface processes (Reed 2006). Several studies have demonstrated the change-detection assessment in short term and multidecadal periods, particularly in coastal areas as related to shoreline changes (Sridhar, Elangovan, and Suresh

Estimation of Snow Accumulation on Samudra Tapu Glacier, Western Himalaya Using Airborne Ground Penetrating Radar

“…However, ground penetrating radar (GPR), a non-destructive technique, can be used to collect both point as well as spatial distribution of snow thickness. It has been widely used in ground mode, for snow and ice thickness measurements [8][9][10][11][12][13][14][15] , snowpack stratigraphic delineation 16 and to study the subsurface properties of other strata 17 . Forte et al 18,19 reported the applications of GPR data in determining the density and electromagnetic (EM) wave velocity for snow, firn and ice.…”