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The mission of the National Earthquake Information Center (NEIC) is to determine rapidly the location and size of all destructive earthquakes worldwide and to immediately disseminate this information to concerned national and international agencies, scientists, and the general public. The NEIC/WDC for Seismology compiles and maintains an extensive, global seismic database on earthquake parameters and their effects that serves as a solid foundation for basic and applied earth science research.

When two oceanic tectonic plates converge, one is subducted or pulled under, the other. This convergent activity allows for magma from the earth's core to erupt at the point of contact. The cooled erupted lava and debris build up over time. When the pile of debris and lava build up high enough, land is formed above sea level. This land is called an island. Often, these island volcanoes stay active, continuously growing.

The Ring of Fire, also known as the Circum-Pacific Belt, is a string of islands with active volcanoes in the Pacific Ocean. This geographical region is the most active volcanic and seismic zone in the world, and corresponds with oceanic-continental convergence of multiple tectonic plates.

An earthquake is what happens when two blocks of the earth suddenly slip past one another. The surface where they slip is called the fault or fault plane. The location below the earth’s surface where the earthquake starts is called the hypocenter, and the location directly above it on the surface of the earth is called

the epicente

How are earthquakes recorded? Earthquakes are recorded by instruments called seismographs. The recording they make is called a seismogram. (figure 4) The seismograph has a base that sets firmly in the ground, and a heavy weight that hangs free. When an earthquake causes the ground to shake, the base of the seismograph shakes too, but the hanging weight does not. Instead the spring or string that it is hanging from absorbs all the movement. The difference in position between the shaking part of the seismograph and the motionless part is what is recorded.