| Summary: | In this thesis, two applications of the F-detector (a processing technique that under certain conditions optimally detects correlated signals crossing an array of seismometers) are described and tested. In the first application, the F trace and its associated probability theory, are used to place uncertainty bounds on the signal-to-noise ratios of P and the depth phases pP and sP arriving on short-period P seismograms recorded at teleseismic distances. The relative amplitude metho~ is often used to determine focal mechanisms that are compatible with the observed relative amplitudes of P, pP and sP. Here upper and lower signal-to-noise ratio bounds on P, pP and sP, calculated using the F trace and its associated probability, are used as the input for the relative amplitude method. This method is tested on several well-studied earthquakes and is found to be effective for earthquakes deeper than around 15 km. The F trace and its associated probability can also be used to help identify depth phases on P seismograms recorded at teleseismic distances, and hence estimate earthquake depth. A method of processing seismic array data to calculate F probability traces which optimally highlight candidate depth phases is developed. The F probability traces are then converted from functions of delay time relative to P, into functions of source depth. These can then be combined for a network of stations to give a single trace which can be interpreted in terms of source depth. This method allows earthquake depths for small-to-medium sized earthquakes to be estimated quickly and with minimal analyst input. The method is applied to a series ofearthquakes located in a range of tectonic environments, it is effective for many of the earthquakes analysed here with body-wave magnitudes greater than approximately 4.0, and depths greater than around 10 km. However in regions where the geological structure is complex (e.g., island arcs), the method gives mixed results.
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