vP0/(m・s−1)

vS0/(m∙s−1)

ε/1

δ/1

The first group

3000

1732

−0.2, −0.1, 0, 0.1, 0.2

−0.2

The second group

−0.1

The third group

0

The fourth group

0.1

The fifth group

0.2