An algorithm of local earthquake detection from digital records

• Main Authors: A. PROZOROV, I. LITVIN, R. CONSOLE
• Format: Article
• Language: English
• Published: Istituto Nazionale di Geofisica e Vulcanologia (INGV) 1978-06-01
• Series: Annals of Geophysics
• Online Access: http://www.annalsofgeophysics.eu/index.php/annals/article/view/4750

The problem of automatical detection of earthquake signals in seismograms<br />and definition of first arrivals of p and s waves is considered.<br />The algorithm is based on the analysis of t(A) function which represents<br />the time of first appearence of a number of going one after another<br />swings of amplitudes greather than A in seismic signals. It allows to explore<br />such common features of seismograms of earthquakes as sudden<br />first p-arrivals of amplitude greater than general amplitude of noise and<br />after the definite interval of time before s-arrival the amplitude of which<br />overcomes the amplitude of p-arrival. The method was applied to<br />3-channel recods of Friuli aftershocks, ¿'-arrivals were defined correctly<br />in all cases; p-arrivals were defined in most cases using strict criteria of<br />detection. Any false signals were not detected. All p-arrivals were defined<br />using soft criteria of detection but less reliability and two false events<br />were obtained.