Monitoring Earthquakes Chapter 6 Section 3
Seismograph • An instrument that measures the vibrations from an earthquake • A seismogram is the recording of the vibrations
Instruments that monitor faults Tiltmeter – two bulbs that are filled with a liquid and are connected by a hollow stem
Instruments that monitor faults Creep Meter – A wire stretched across a fault and attached to a post on one side and a weight and pulley on the other.
Instruments that monitor faults Laser Ranging Device – times how long a laser beam travels to and back from a reflector. A change in time indicates a change in distance.
Instruments that monitor faults GPS Satellites – satellites are used to measure the movements of markers on opposite sides of a fault
Predicting Earthquakes • When friction between the opposite sides of a fault is high, the fault locks and stress builds up until an earthquake occurs • Geologists know that wherever plate movement stores energy in the rock along faults, earthquakes are likely.
Predicting Earthquakes • We cannot yet predict earthquakes because we can’t be sure when and where stress will be released along a fault Video