FROM LAYER CAKE TO COMPLEXITY: 50 YEARS OF GEOPHYSICAL INVESTIGATIONS OF THE EARTH

Geophysical observations of earth structure, kinematics and dynamics have served as a core driver in the development of our current understanding of how the earth evolves. They have provided essential insights that inform our ability to mitigate its hazards and effectively utilize its critical resources. Since the 1960’s, when geophysical measurements played a central role in establishing the plate tectonics paradigm, geophysical techniques have become an increasingly sophisticated mainstay in our scientific toolkit for addressing a wide range of scientific and societal needs. From detailing the complex structural and compositional heterogeneities of the earth’s lithosphere and mantle to monitoring the tectonic processes which shape the earth’s surface and deep interior; from finding and monitoring the extraction of critical natural resources that are increasingly rare to real time warning systems that can provide life-saving alerts of tsunami and seismic shaking, geophysics continues to play an increasingly important role in our lives. The myriad ways in which geophysics has revolutionized our understanding of our planet, from core to ionosphere, are too vast to properly represent in any single review. Presented here are selected highlights from the myriad geophysical investigations of the solid earth over the past 50 years. These selections, though biased and superficial, should convey both the impressive past impact and future promise of the field.