Accurate Method for Picking Up the First Arrival Time of Microseismic Signals Based on Entropy Theory

Table 3

Summary of the pickup time for different methods with different SNRs.

Method	1	2	3	4	5	6	7	8	9
	No added noise
STA/LTA method	1012.2	1012.4	1012.5	1012.3	1012.2	1012.1	1012.0	1012.4	1012.2
Fractal method	1011.3	1011.4	1011.5	1011.4	1011.3	1011.4	1011.4	1011.5	1011.3
Entropy method	1011.2	1011.3	1011.4	1011.3	1011.2	1011.3	1011.4	1011.4	1011.3
	Added noise of 20 dB
STA/LTA method	1012.4	1012.6	1012.7	1012.5	1012.4	1012.3	1012.2	1012.6	1012.4
Fractal method	1011.5	1011.6	1011.8	1011.8	1011.5	1011.7	1011.5	1011.9	1011.5
Entropy method	1011.4	1011.5	1011.6	1011.5	1011.4	1011.5	1011.4	1011.6	1011.4
	Added noise of 10 dB
STA/LTA method	1013.5	1013.6	1013.7	1013.5	1013.4	1013.3	1013.2	1013.6	1013.4
Fractal method	1012.2	1012.3	1012.4	1012.7	1012.1	1012.4	1012.0	1012.4	1012.1
Entropy method	1012.0	1012.1	1012.1	1011.9	1011.8	1011.8	1011.7	1011.9	1011.7
	Added noise of 2 dB
STA/LTA method	1015.1	1015.2	1015.4	1015.1	1015.0	1014.9	1014.8	1015.2	1015.0
Fractal method	1013.9	1014.0	1014.2	1013.8	1013.7	1013.4	1013.2	1013.9	1013.6
Entropy method	1012.9	1012.9	1013.0	1012.7	1012.7	1012.6	1012.3	1012.9	1012.7