Arrival time measurements of first arrival phases P and PKIKP using the method of fixed scale wavelet transformation ratio

Introduction Usually there are abundantly transient high-frequency compositions and weak amplitudes at the onset of a gradually changing signal. Using the method of the fixed scale wavelet transforma- tion ratio, we tried to display and measure the onset time or first arrival time. Unfortunately, the ratio method is lack of the stability. To reduce the noise influence on the ratio, reveal the arrival time information and improve the measurement precision of the arrival time of the gradually ch…

Arrival time measurements of first arrival phases P and PKIKP using the method of fixed scale wavelet transformation ratio

The arrival times of first teleseismic phases are difficult to be measured precisely because of slowly and gradually changed onsets and weak amplitudes. The arrival times measured manually are usually behind the real ones. In this paper, using the ratio method of fixed scale wavelet transformations improved by us, the arrival times for the first arrival phases (such as P and PKIKP) at the teleseismic and far-teleseimic distances were measured. The results are reasonable and reliable based on the analysis and discussion of the reliabilifies and errors.