GIS-based analysis in marine geomorphological research by example of White Sea
ISBN 978-85-88783-11-9
Authors
1Sergeev, I.; 2Egorov, I.
1St. Petersburg State University Email: igorsergeev.spb@gmail.com
2St. Petersburg State University Email: ieg@mail.ru
Abstract
The specificity of geomorphological research of subaqueous relief, primarily, resides in the lack of possibilities for the direct object study, as it is carried out in the ground conditions. Authenticity and accuracy of the results depend on the resolution of the bottom assaying network and on the presence of ancillary data (such as the geophysical measurements, underwater television observation, etc.). The development of systems for the spatial data collection, organization and analysis (geographic information systems - GIS) allows effectively gaining various information concerning the structure and the genesis of underwater relief. The most important specificity of GIS use in marine geomorphology is the possibility to select key information from a large amount of initial data and to create adequate models of geomorphological seabed structure. In present work we consider the use of geographic information systems in the ArcGIS environment for performing geomorphological zoning of the White Sea shelf. Numeric bathymetry records were used as the initial data. To carry out further graphic-analytical construction digital surface model was created. Statistical processing of the surface digital model determined the principle of geomorphological zoning for the White Sea shelf. It is based on the allocation of bathymetric values sets gravitating to the nearest anomalous value on the distribution curve. These depth values reflect the subhorizontal surfaces with the set of certain characteristics. The morphology of the relief for seven identified sub-horizontal surfaces on the bottom of White Sea is examined and compared with the statistical signs. Based on this analysis and the existing notions about geomorphology of the White Sea bottom, the causes of the formation for these geomorphological regions of the White Sea bottom were examined. When considering the vertical curvature abnormally high values of this geomorphological parameter were observed for two of the surfaces located deeper than 130 meters. These values fall out of the general series and according to the analysis their origin can be determined by the intensive tectonic processes. We examined "Intensity of vertical curvature" concept for the relief model. This indicates the surface borders distribution of the earth crust deformations and generally coincides with the tectonic data on the explored region.