Soil type

Materials tested

Height of testing

Operation speed or frequency

Performance of study

Reference

Water

Pipe

12 m

3 - 25 kHz

One food buried in sand

[85]

Space

M2, M16 anti personnel mine

1 - 13 cm

-

13 cm

[88]

Space

Aluminum 5 × 5 × 0.15 cm

Iron nail 3 × 0.3 cm

20 cm

10 cm

1 kHz

20 cm

10 cm

[89] [90]