Summary of Abstract Submission

Abstract Submission No. IO50-08-0019PresentationPoster


V.P. Mahale*1, G.H Ranade1, Sanjeev Afzulpurkar1, Rahul Sharma1

1 National Institute of Oceanography, India


Seamounts are undersea volcanoes that are typically cone shaped. Most of the high-relief seamounts across the oceans have been mapped on a coarse resolution by employing satellite altimetry technique. This satellite based technology provides an indirect method to generate relief of the seafloor topography from space. This time-tested technique reports two such prominent undersea features along the western continental shelf rise, off Malvan, central west coast of India. These charted features appear on all the nautical charts published for the region. The charted summit elevation of these two feature is as high as 252 m and 343 m, on a relatively flat base at 1106 m. Undersea features present in and around the Indian Ocean region lacks detail studies as apparent from the fact that an isolated elevation of the order of 850 m are untracable. It is well understood that the bathymetric estimates derived from altimeter over-estimates narrow peaks and under-estimates trenches. The two seamounts under review are of considerable size i.e. approximately 3.5 km by 2.5 km as indicated on the nautical charts and are spaced approximately 20 km apart. Recently, during a HAT/SAT cruise of Atlas DS-3 multibeam echosounder installed onboard RV Sindhu Sadhana, the above mentioned seamounts were undetected. Hunting to locate the seamounts went on until an area of the order of 30x40 sq km was densely mapped using high-resolution shipboard soundings, but to no avail. The paper mainly focusses on mapping aspect and inferences on why such shallow depths were ever been recorded.