GEOLOGY

Detailed explanation-1: -Creepmeters. A creepmeter measures fault slip by recording the displacement between 2 piers or monuments located on opposite sides of the fault, spaced 30 meters apart. Typically, an invar wire (or a graphic rod) is anchored to one pier and is stretched across the fault.

Detailed explanation-2: -A creep meter uses a wire stretched across a fault to measure horizontal movement of the ground. A laser-ranging device uses a laser beam to detect horizontal fault movements. A network of Earth-orbiting satellites called GPS helps scientists monitor changes in elevation as well as horizontal movement along faults.

Detailed explanation-3: -Geologists use seismographs to record the surface and body waves. Inside a seismograph designed to measure horizontal motion, a weight is freely suspended.

Detailed explanation-4: -What four instruments are used to monitor faults? Tiltmeters, creep meters, laser-ranging device, and GPS satellite.

Detailed explanation-5: -The correct answer is (a). seismograph. This is the advanced instrument used to perceive and measure seismic waves.