Presentation on theme: "Monitoring Earthquakes Chapter 2, Section 3. Did you Know? The problem of predicting Earthquakes is one of the many scientific questions that remains."— Presentation transcript:
Did you Know? The problem of predicting Earthquakes is one of the many scientific questions that remains unsolved!
It is important for scientists to develop ways to predict earthquakes because: A warning allows people who live in the area to protect themselves by: – Reinforcing buildings and other structures – Getting emergency supplies – Evacuating
Earthquakes are dangerous, so scientists are trying to monitor them (monitor =watch closely) What do scientists use to monitor and measure Earthquakes now?
SeismoGRAPH The machine that measures earthquake seismic waves
Geologists hypothesize that along a fault, they can monitor the stress buildup in the crust to predict when an earthquake might occur
Geologists measure the STRESS in the Earth’s crust on either side of faults, looking for: a slight rise or fall in the elevation (height) of the crust the tilt of the crust and the distance of horizontal ground movement
Tiltmeters Measures the “tilting” or lift of the crust on either side of the fault Consist of two contraptions that are filled with liquid and connected by a hollow stem If the land rises or falls slightly, the liquid will flow from one contraption to the other
Creep Meter Uses a wire stretched across a fault to measure horizontal movement of the ground One side of the fault, the wire is anchored to a post On the other side, the wire is attached to a weight that can slide if the fault moves
Used on Strike-Slip faults Uses a laser beam to detect horizontal fault movements The device times a laser beam as it travels to a reflector and back The device can detect any change in distance to the reflector
GPS (Global Positioning System) Scientists can monitor changes in elevation AND horizontal movement along faults Scientists can see changes in elevation and horizontal movement Used for Normal, Reverse, and Strike-Slip Faults
The movement along faults depends on how much friction there is between the sides of the fault Friction: the force that opposes the motion of one surface as it moves across another Low Friction = no Earthquake Moderate Friction = small Earthquake High Friction = big Earthquake
Did You Know? Even with data from many sources, geologists cannot predict when and where an Earthquake will strike Reasons: – Sometimes stress builds up along a fault, but an Earthquake does NOT occur – Sometimes an earthquake relieves stress in an unexpected part of a fault
The problem of predicting Earthquakes is one of many scientific questions that remains unsolved!