Plate Tectonics

By Adarc

  • John Winthrop

    first person to study earthquakes

  • Observational Seismology

    R. Mallet goes to Italy to study the aftermath of an earthquake, He learned that earthquake waves radiate from a center.

  • First Seismograph

    First time-recording Seismograph built in Italy by F. Cecchi

  • First Seismograph in Norith America

    First Seismograph installed at Lick observatory in California.

  • Seismometer

    E. Wiechert makes the first seismometer with
    viscous damping,

  • Waves

    R. Oldham identifies P, S, and surface waves.

  • Moho Boundary

    Velocity boundary between the mantle and crust found by A. Mohorovicic

  • Richter Scale

    C. Richter creates a scale measuring the magnitudes for sizes of earthquakes.

  • Inner Core

    I. Lehmann discovers the solid inner core.