Based on the water tube tiltmeter observatory data, the author analyses the ground tilt tide, finds that the abnormal changeofamplitude factors of EW and NS componts is corresponding to earthquakes.
The greater the amplitudechangeof head wave of transverse velocity is, the severer the damage is, the later the arriving time of the first wave hollow and the longer the damaged element will be.
Gain Change: Adjust the amplitudeof some portion of a sample Normalize: Set the amplitude of the loudest portion to 100% and scale the rest accordingly.