PROBING THE DEEP EARTH

SEISMOLOGY USES THE TRAVEL TIMES AND AMPLITUDES OF SEISMIC WAVES TO STUDY VARIATIONS IN SEISMIC WAVE VELOCITY AND DENSITY

GRAVITY STUDIES MEASURE VARIATIONS IN DENSITY

MAGNETIC STUDIES GIVE INSIGHT INTO THE CORE'S MAGNETIC FIELD

TOGETHER WITH RESULTS FROM LABORATORY STUDIES OF ROCK PROPERTIES AND OTHER DATA THESE YIELD OUR MODELS OF THE EARTH'S COMPOSITION, TEMPERATURE, AND INTERNAL PROCESSES