Plate Tectonics

Plate Tectonics

“Developed from the 1950s through the 1970s, plate tectonics is the modern version of the continental drift, a theory first proposed by scientist Alfred Wegener in 1912. All of the continents, at one time, were connected and formed a single super-continent called Pangaea. This explains why the coastlines of the continents appear to fit together like pieces of a puzzle. During hundreds of millions of years, the plates have moved and changed position. Sometimes they move together, sometimes they separate and move apart and sometimes they move past each other. When the plates move past each other, they sometimes touch and make one plate rise up as the other slides down. That up and down movement causes an earthquake, which results in a land fault or crack. If the movement happens in a large body of water, it can create giant water waves called tsunamis.

Yellowstone National Park

Millions of years ago, a source of immense heat known as a hotspot formed in the Earth’s mantle below what today is Yellowstone. Roughly 600,000 years ago, the hotspot pushed a large plume of magma toward the Earth’s surface. This caused the crust to jut upward. The Yellowstone Plateau became a geomorphic landform shaped by episodes of volcanic activity. Stress also caused rocks overlying the magma to break, forming faults and causing earthquakes. Eventually, these faults reached the deep magma chamber. Magma oozed through these cracks, releasing pressure within the chamber and allowing trapped gases to expand rapidly. A massive volcanic eruption then occurred along vents, spewing volcanic ash and gas into the atmosphere and causing fast super-hot debris (pyroclastic) flows on the ground. As the underground magma chamber emptied, the ground above it sunk, creating the first of Yellowstone’s three calderas.

Not only is Yellowstone National Park considered to be an active volcano, it is considered to be a super volcano meaning it is capable of massive eruptions of more than 240 cubic miles of magma. Two of the last three major eruptions were at least that big with massive ash plumes that covered large portions of North America. Scientists with the Yellowstone Volcano Observatory actively monitor Yellowstone’s volcanic activity watching for changes that might indicate the likelihood of another major eruption. For the most part geologic activity