Vibratory probe is also called as terra probe, which consists of a vibrodriver coupled to an open-ended steel tubular probe of 760mm diameter and 15mm length. The vibrodriver activises the probe to vibrate in the vertical direction and imparts impulse normally at 15 Hz with 10 to 25 mm amplitude. This vibration enables the vertical pipe to penetrate the loose material. The probe is sunk to the desired depth and held for 30 to 60 seconds before extraction. A spacing of 1 to 3m is generally adopted. The square pattern is followed with a fifth probe at the center of each square to achieve an increase of densification, instead of adopting a reduced spacing. Sometimes a water jet may be used to help easy penetration of the probe for sites where the water table is deep but the operation of jet has to be stopped during withdrawl. This technique is considerably faster than the vibroflotation procedure.