Seismological Research Letters , 83, 3, 531-540, 2012, doi: 10.1785/gssrl.83.3.531
A. Lomax, C. Satriano and M. Vassallo
Abstract
Most earthquake location algorithms are based on ray-theory travel-times and thus require as input data the onset times of body-wave phases such as P and S at a number of stations. It is often easy to detect and pick the first P onset times manually since the human eye can identify a change in amplitude or frequency in a signal even in the presence of high noise levels. The picking of S-phase onsets is more difficult because these onsets are often emergent and buried in the P coda, though at very short ranges the S onset can be impulsive and of high amplitude relative to the P coda. Automatic detection and picking of phase onsets is much faster and can be more consistent than manual processing; thus, automated methods are necessary for large datasets and for real-time systems. However, robust, automatic,real-time detection and picking of phase onsets on noisy, broadband signals is a difficult algorithmic task.
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