Question

distinguish between echo and re vibration

Answer 1

A reverberation is perceived when the reflected sound wave reaches your ear in less than 0.1 second after the original sound wave. Since the original sound wave is still held in memory, there is no time delay between the perception of the reflected sound wave and the original sound wave. The two sound waves tend to combine as one very prolonged sound wave. If you have ever sung in the shower (and we know that you have), then you have probably experienced a reverberation. The Pavarotti-like sound which you hear is the result of the reflection of the sounds you create combining with the original sounds. Because the shower walls are typically less than 17 meters away, these reflected sound waves combine with your original sound waves to create a prolonged sound - a reverberation.

Answer 2

ECHO:-
Echo is a reflection of sound that arrives at the listener with a delay after the direct sound. The delay is proportional to the distance of the reflecting surface from the source and the listener.

RE VIBRATION:-
Re vibration is delayed application of vibration to concrete which has placed and compacted already. When first layer is vibrated and may have hardened partially and application of vibration is transmitted to the underlying layer. In some cases this is done intentionally. 
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