seismology Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other ...

, a seismic trace refers to the recorded curve from a single

seismograph A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The output ...

when measuring ground movement. The name comes from the curve plotted by a seismograph as the paper roll rotated and the needle left a trace from which information about the subsurface could be extracted. Today's instruments record the data digitally and the word trace has come to mean the digital curve.

Complex seismic trace

The recorded seismic trace is considered the real part of the complex trace. By phase shifting the recorded trace by 90 degrees, we can obtain the imaginary part of the complex trace. The complex seismic trace is a

complex function Complex analysis, traditionally known as the theory of functions of a complex variable, is the branch of mathematical analysis that investigates functions of complex numbers. It is helpful in many branches of mathematics, including algebraic ...

whose real and imaginary part are the previously mentioned. From the complex trace, one can now define

seismic attribute In reflection seismology, a seismic attribute is a quantity extracted or derived from seismic data that can be analysed in order to enhance information that might be more subtle in a traditional seismic image, leading to a better geological or geo ...

s such as the complex amplitude, phase, instantaneous phase and instantaneous frequency.

References

Seismology measurement Seismology {{Seismology-stub