Determination of First Arrival Wave Type of Microseismic Signals and Approach to Wave Velocity Correction

Table 1

Determination of wave velocity type.

	Corresponding wave type of r1	Corresponding wave type of ri	Corresponding wave type of arrival time difference
ti − t1 > TLP1i	P	P	P
TLP1i < ti − t1 ≤ TLS1i	P or S	S	S
TLS1i < ti − t1 ≤ TLR1i	P, S, or R	R	R
TLR1i < ti − t1 ≤ TLPR1i	P or S	R	R
ti − t1 > TLPR1i	Abnormal wave	Abnormal wave	Abnormal wave