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an imaginary line that passes through Earth's center and the north and south poles, about which Earth rotates
The two days of the year on which the noon sun is directly overhead at either 23.5 degrees South or 23.5 degrees North
the blocking of sunlight to earth that occurs when the moon is directly between the sun and earth
the blocking of sunlight to the moon that occurs when Earth is directly between the sun and the moon
attractive force between two objects that depends on the masses of the objects and the distance between them
an explosion of hydrogen gas from the sun's surface that occurs when the loops in sunspot regions suddenly connects
an undersea mountain chain where new ocean floor is produced; a divergent plate boundary
a device that determines the distance of an object under water by recording echoes of sound waves
a deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle
the process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary
a device that records ground movements caused by seismic waves as they move through Earth
The measurement of an Earthquake's strength based on seismic waves and movement along faults
A scale that rates earthquakes according to their intensity and how much damage they cause
a scale that rates seismic waves as measured by a particular type of mechanical seismograph
moment magnitude scale
a scale that rates earthquakes by estimating the total energy released by an earthquake
vibrations that travel through Earth carrying the energy released during an earthquake
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