Precursory Indicator for Mode I Fracture in Brittle Rock through Critical Slowing Down Analysis

Table 1

Fracture toughness and total AE hit of specimens.

Specimen no.	Mode I fracture toughness (MPa × m^1/2)	AE hit total
M1	0.797	21101
M2	0.734	13659
M3	0.527	19071
M4	0.783	25153
M5	0.596	20347
M6	0.569	16699
M7	0.447	27321
Average	0.636	20479