Word: moho
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Dates: during 1959-1959
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...years. Novelist Arthur Conan Doyle, who visualized the earth's shell as a living creature, made his fictional Professor Challenger poke a sharp drill eight miles down, called his story When the World Screamed. AMSOC's goal is to pierce the Mohorovicic discontinuity, which scientists call the Moho for short...
Flexible Finger. The Moho was discovered in 1909 by Seismologist A. Mohorovicic of Yugoslavia, when he noticed that the speed of earthquake waves increases suddenly at a certain level under the earth's surface (the depth varies from place to place). This suggested that the Moho marked a dividing line between different materials. Geologists believe that the Moho is the bottom edge of the granite and basalt that forms the lower layer of the earth's crust; under it is the earth's mantle consisting of a mixture of silicates and nickel-iron, which in turn encloses...
...drilling cannot be done on the continents because they are great rafts of granite "floating" in deeper plastic material. The granite is too thick (20 miles) to drill through. Oceanic islands are also ruled out as drilling sites; their weight has pressed the Moho to an impossible depth. The best place to drill is the floor of the great ocean basins. The floor may be three miles beneath the ocean's surface, but the Moho lies only three or four miles deeper, under a thin skin of sedimentary deposits and a layer of basalt...
First step toward the Moho would be to drill a cone-shaped hole in the sea bottom. The hole would be filled with cement poured down the drill stem and a steel platform fixed in the cement. The rock drill would be passed through this steel collar and turned from the barge. The long drill stem would be flexible enough to allow for the ship's motions...
...sample wells off California in water 1,500 ft. deep. Drilling in three miles of water would be harder, but Geologist Bascom thinks it can be done. So do the Russians, who claim to have drilling equipment just as good, and are apparently trying to beat AMSOC to the Moho...