Geoscience Reference
In-Depth Information
1
Basic Earth Science and Society
INTRODUCTION
Human society is built upon a terrestrial foundation. Forests, farmlands, and
cities are rooted in the Earth, and people draw sustenance from its outer layers in
the form of water, food, minerals, and fuels. Earth science is thus a practical
enterprise on which our society's survival depends. It is also a fundamental quest
for understanding the natural world—an exploration to learn about the origin,
evolution, and future of our planetary home. Curiosity about these basic issues
sustains scientific inquiry even in areas where the utility of the research is less
than obvious.
In fact, the fundamental and practical aspects of Earth science are intimately
interwoven. Seismological and potential-field techniques developed for finding
oil and minerals are now employed to image churning structures thousands of
kilometers deep within the Earth's connecting mantle. These great thermal
currents continually rejuvenate the face of Earth through plate tectonics, raising
mountains, and causing earthquakes and volcanic eruptions. Helical motions even
deeper, within the liquid outer core, generate the magnetic field that guides the
compass and helps to shield the Earth's biosphere from solar and cosmic
radiation. Efforts to simulate the deep-seated machinery of mantle convection and
the core dynamo are stretching the limits of computing technology and providing a
dynamical framework for synthesizing many previously disparate observations.
On a more local scale, the methods of analytical geochemistry developed for the
study of minerals, rocks, and soils have become powerful weapons in the fight
against toxic pollution. Ultraprecise positioning techniques of space geodesy have
measured the continental drift postulated by Wegener; they now monitor the
accumulation of strain across dangerous faults such as California's San
