Chapter 1 - Introduction

Abstract

This chapter provides an overview of ocean mapping, ocean floor mapping, and underwater geology. Accurate navigation at sea became possible only with the development of accurate and reliable chronometers in the eighteenth century, and it enabled longitude to be determined. Nowadays, there are many radio-navigational aids, both surface and satellite mounted. Accurate depth determinations became possible with the development of echo-sounding. Direct imaging of the sea-floor, as distinct from bathymetric mapping, is achieved by side-scan sonar instruments. Satellite altimetry uses radar to precisely measure the average height of the sea-surface, which follows a surface of equal gravitational potential—the geoid. These measures helped in mapping oceans and ocean floors. Detailed exploration of oceanic crustal structure and composition began with the Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) that provided information on underwater geology. Today, much has been learned about oceans with the help of new technologies for imaging and through submersible operations.