The reduction and analysis of seismic data using digital computers.

ALTHOUGH THE DEVELOPMENT AND INSTALLATION OF SEISMIC ARRAYS DURING THE PRESENT DECADE HAS CONSIDERABLY IMPROVED THE QUALITY OF SEISMIC DATA AVAILABLE, THESE ARRAYS HAVE NOT, AS YET, HAD THE IMPACT IN THE FIELD OF SEISMOLOGY WHICH MIGHT BE EXPECTED. ONE OF THE PRINCIPAL REASONS FOR THIS, AND WITH WHICH THIS THESIS IS' PRIMARILY CONCERNED, IS THE REQUIREMENT OF MEANS OF PROCESSING THE ARRAY OUTPUT, EITHER AUTOMATICALLY OR SEMIAUTOMATICALLY, IN ORDER TO UTILIZE THE ADVANTAGES WHICH'AN ARRAY . CAN PROVIDE. THE INITIAL PART OF THIS THESIS DESCRIBES A SYSTEM, .USING A: GENERAL PURPOSE DIGITAL COMPUTER, WHICH HAS BEEN DEVELOPED TO PROCESS THE OUTPUT OF THE WARRAMUNGA ARRAY IN AUSTRALIA. USING THIS SYSTEM THE FOLLOWING TOPICS, WHICH ARE DISCUSSED HEREIN, HAVE BEEN STUDIED'. 1. THE INITIAL AUTOMATIC DETECTION OF SEISMIC EVENTS. THIS PROBLEM HAS BEEN INVESTIGATED USING TWO DIFFERENT APPROACHES. THE FIRST HAS BEEN TO SIMULATE AN ON-LINE DETECTOR AT THE ARRAY WHILE THE SECOND IS A FEASIBILITY STUDY OF DETECTING EVENTS USING A DIGITAL COMPUTER. 2. THE EDITING OF SEISMIC EVENTS IN ORDER TO REDUCE DATA STORAGE REQUIREMENTS AS WELL AS TO IMPROVE DATA ACCESSIBILITY. 3. THE MEASUREMENT OF THE AZIMUTH AND APPARENT VELOCITY OF SEISMIC EVENTS. 4. THE INVESTIGATION OF METHODS WHEREBY AN AUTOMATIC ANALYSING SYSTEM CAN OVERCOME THE PROBLEM OF SPURIOUS NOISE ON THE ARRAY RECORDS WITHOUT EXTREME DEMANDS ON THE USE OF A COMPUTER. IN ADDITION TO THESE TOPICS, THE ENHANCEMENT OF SEISMIC EVENTS USING AN ARRAY IS DESCRIBED TOGETHER WITH RESULTS OF PROCESSING SEISMIC EVENTS.