Why is this circuit not working?
Your LDR when exposed to light changes its resistance which in combination with the potentiometer make a voltage-divider. This changes the voltage on the TR (trigger) pin of the NE555 and causes it to change its output.

The vibration sensor does not work this way, In your schematic you have shorted the output of the sensor to 12V line on BAT1. In your circuit remove the connection of RV1 to 12V and instead connect it to the output of the sensor.