Sometimes BIG vibrations. These vibrations can be detected by sensitive devices called seismometers . Data from the seismometer is sent to a seismograph where it is recorded. The image above shows the seismograph in Sunset Crater Volcano National Monument's visitor center. Each day the paper record, called a seismogram , is removed and replaced with a new one.
Scientists then analyze the earthquake data from the seismogram.
Seismographs can help us determine the time, epicenter , focus , and the type of faulting that produced an earthquake as well as estimate how much energy was released. The image on the right shows a close-up of one of eight earthquakes recorded on Sunset Crater's seismograph on October 18, 1998. Most of the time the seismograph pen draws a fairly smooth line, telling us that no earthquakes have occurred within range of our seismograph's sensitivity. Most of the lines in this image are smooth, with regular 'blips' that scientists use to help keep track of the time of day. The story starts beneath the surface.