earths structure chapter 16
Terms
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- volcano
- a fissure in the earth's crust (or in the surface of some other planet) through which molten lava and gases erupt
- convection current
- is the flow that transfers heat within a fluid. The heat from the earth's mantle and core causes convection currents to form in the astenosphere and throughout the mantle. The heating and cooling of the fluid, changes in the fluid's density, and the force of gravity combine to set convection currents in motion.
- plate tectonics
- the branch of geology studying the folding and faulting of the earth's crust
- continental drift
- the gradual movement and formation of continents (as described by plate tectonics)
- outer core
- liquid layer of the Earth's core
- earthquake
- shaking and vibration at the surface of the earth resulting from underground movement along a fault plane of from volcanic activity
- crust
- the outer layer of the Earth
- focus
- maximum clarity or distinctness of an image rendered by an optical system
- epicenter
- the point on the Earth's surface directly above the focus of an earthquake
- plate
- a rigid layer of the Earth's crust that is believed to drift slowly
- mantle
- a sleeveless garment like a cloak but shorter
- inner core
- solid, dense center of the Earth
- Alfred Wegner
- in the 1900's propsed a theroy tht the continents were once together and have drifted apart?
- ring of fire
- Collection of volcanoes rimming the Pacific Ocean, really a ring of subduction zones
- modified mercalli scale
- a subjective damage scale that indicates earthquake intensity
- seismograph
- a measuring instrument for detecting and measuring the intensity and direction and duration of movements of the ground (as an earthquake)
- seafloor spreading
- is magma slowley pushed up through the cracks in the rift then cools and forms a new sea floor
- richter scale
- a logarithmic scale of 1 to 10 used to express the energy released by an earthquake