| Popis: |
An investigation to combine REMODE with velocity filtering over a three component array in order to enhance depth phases experienced considerable difficulty in aligning P and pP phases simultaneously. To explain this difficulty, seismograms from four earthquakes were analyzed at the 9 sites in the TFO Extended Array. The depth phase (pP) is well-defined on these seismograms. It is established that the time difference (pP-P) at the 9 stations of the array differs by as much as 0.5 seconds for the same earthquake. It is concluded that each phase P, pP, and in one case sP, has its own travel time anomalies for the TFO Extended Array. It is further concluded that REMODE should be applied to the three component seismograms, rather than to the sum of the horizontal and vertical components of the array. |
