Marine geophysics / Морская геофизика

Exploration of the oceans using the techniques of the geophysicist has had a profound influence on our understanding of the Earth and its behaviour through time. Observations in the deep ocean have played a key role in establishing modern plate tectonic theory, transforming Earth Science in ways that were quite unexpected when the first geophysicists put to sea. Measurements in shallower waters have revealed how continental margins form, subside and become covered with sedimentary accumulations. The remarkable structural details revealed by seismic and other methods in these regions make geophysics an indispensable tool in the search for petroleum and other natural resources. After a long period of exciting developments, it is now appropriate to review what geophysics can tell us about the structure of the seabed and the ways in which the oceans and their margins have evolved.
Rapid progress in marine geophysics, as in other branches of science, has been closely linked to advances in technology. The first part of this volume therefore focuses on the instruments and methods for making geophysical observations at sea. The means of accurately locating sensors and mapping seabed topography are essential for investigations of the solid Earth. Following an introductory chapter, these topics are considered in Chapters 2 and 3. I then discuss the powerful seismic techniques for imaging the Earth’s interior. Chapters 6-10 examine the gravity and magnetic fields over the oceans, heat loss from the sea floor, together with electrical and radiometric methods for studying submarine geology. Geophysical measurements in offshore boreholes are reviewed in Chapter 11. Wide-ranging observations are brought together in later chapters on the structure and evolution of the deep sea floor, continental margins and areas where lithospheric plates converge. On completing each section I have been keenly aware of field studies and developments in instrumentation and data analysis that receive only scant mention or have had to be omitted altogether in order to keep the book to a manageable size. To provide some compensation for the action of information filters the reader is directed to further lit erature which is not cited in the main text.