New earthquake facts are still being discovered
New earthquake facts are being discovered by scientists constantly. Our family lives on the Pacific Ring of Fire in the Cascadia Subduction Zone. People in our area are being warned that we are overdue for a major earthquake. The plates are locked and the tension in the rocks is increasing.
2011 Japan earthquake and tsunami destruction
Converging tectonic plates
Plates moving on the surface of the Earth converge in areas all over our planet. If two continental plates converge the result are towering mountain ranges like the Himalayan Mountains. The collision of the Indian Plate and the Eurasian plate smashing together has created the Himalayan Mountains and the Tibetan Plateau.
P waves and S waves are body waves
Earthquake facts on seismograms led to the discovery that all earthquakes produce P waves and S waves. Small and large earthquakes produce seismic waves when rocks break apart. P waves and S waves are called body waves because they travel through the interior (body) of the Earth. Scientists studying earthquake waves inside the earth have discovered three major boundaries.
Our Earthquake book is packed with fascinating earthquake facts plus an activity in each chapter. Chapter topics in the book include Earthquake History, San Andreas Fault, Moment Magnitude Scale and Preparing for Natural Hazards. Myrna Martin
Andrija Mohorovicic looking for earthquake facts about the inside of the Earth discovered a boundary that varied depending whether it was below continental plates or oceanic plates. He had discovered the boundary between the crust and the mantle. The boundary was named the Mohorovicic discontinuity often shortened to Moho.
Beno Gutenberg looking for earthquake facts about the Earth below the Moho boundary discovered that S waves stopped at a secondary boundary inside the Earth. He knew these two earthquake facts. S waves only travel through solids and P waves travel through solids, liquids and gases. Gutenberg then knew that inside the Earth was a liquid core that stopped the S waves.
Solid inner core
Inge Lehmann, a Danish seismologist, discovered the solid inner core using the speed and path of P waves that originated in New Zealand. She discovered that P waves slowed down in the liquid outer core and then sped up for a short time. She realized from these earthquake facts that the Earth has a solid inner core inside the liquid outer core.
Plate movement creates earthquakes
Scientists looking for earthquake facts about plate movement used the information gathered from seismographs all over the Earth. They discovered that most earthquakes are produced by plate movement. They used seismograms that are the written records produced by a seismographs to plot the exact location of earthquakes.
Scientists then discovered earthquake facts they gathered from the seismographs created earthquake zones. These zones of earthquakes showed the boundaries of the crustal plates that are moving on the surface of the Earth.
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