Seismology is the study of earthquakes and the seismic waves they produce. The movement of seismic waves is detected and recorded by seismographs. The detection involves the separation of events from the ever-present background of seismic noise. Pinpointing sites of events has become very accurate since the development of precise instrumentation and the establishment of the World Wide Standard Seismograph Network (WWSSN). Seismology is very important in the exploration of Earth's internal structure.