AUTOMATIC PHASE PICKING USING AKAIKE INFORMATION CRITERIA (AIC)

In order to estimate source parameters (latitude, longitude, depth and origin time), arrival times of P- and S-waves have been identified/read on seismograms and then processed by a location algorithm. This algorithm requires preparation of an input file consisting of phase readings. Excessive increase in the amount of digital data in recent years has increased workload of seismologists. Thus, many researchers over the world have developed different methods based on automatic phase picking. One of these methods is the Akaike Information Criteria (AIC). Arrival times of P- and S-waves of three earthquakes in this study have been determined by this method and its reliability has been tested by comparing observed arrival times with automatically determined ones. As a result of this comparison consisting of 104 seismograms, 85% of time differences between automatic and manual readings is distributed between 0 and ±0.5sn. The reason of larger residuals in time differences is that automatic P-wave arrival times are also picked from horizontal components that are not usually used in manual phase readings of P-waves and determination of arrival times is difficult if the signal to noise ratio is very low in an earthquake record