An electrostatic servo silicon accelerometer with mG resolution for measurment of the seismic movement was developed. The sensor is composed of a glass-silicon-glass structure by using bulk silicon micromaching techniques. It has a mass and four suspending beams. The working range of the sensor is ±1G and operating frequency bandwidth is 1kHz. The resolution is 1.6mG. To achieve high sensitivity thin beams are required for springs and shield electrodes are formed on the glass to prevent an electrostatic bonding of the beam to the glass.