Earthquakes Modified

Transcription

1 Plate Tectonics Earthquakes Modified Recall that the earth s crust is broken into large pieces called. These slowly moving plates each other, each other, or from each other. This causes much on the rocks. Plate Boundaries The is an area bordering the Ocean where many earthquakes and volcanoes occur. and result in movement along fault lines causing earthquakes and volcanic eruptions Stress on Rocks rocks move together rocks move away from each other rocks slide past each other Faults A or zone of fractures between two blocks of rock. These blocks relative to each other. A quick movement along fault lines results in an. There are main types of faults.

2 Normal Fault Earthquakes Modified -rocks move away from each other Hanging wall moves relative to the foot wall. Reverse Fault rocks move toward each other The hanging wall relative to the footwall. Strike-Slip Fault shearing rocks slide past each other Rocks are displaced mainly in a, parallel to the fault line. Example: San Andreas Fault in California Earthquakes Occurs when the built up along a fault line becomes so great that the rocks on either side of the fault suddenly. This pent-up pressure is released as. Energy radiates out in the form of waves. Earthquakes (cont.) This energy results in, which sometimes causes great destruction. Small earthquakes happen frequently, but large ones are more and difficult to. Smaller occur after the main event.

3 Layers of the Earth Review Crust outer layer Mantle plastic-like Outer Core - Inner Core - Seismograph An that measures and records details of earthquakes. Determines the and the of an earthquake the record produced by the seismograph a scientist who studies earthquakes. Seismic Waves P Waves ( ) waves to arrive at the seismic station (fastest) Can move through the and layers of the earth Considered a wave Shakes the ground back and forth ( ) Seismic Waves S Waves ( ) than P Wave Can move through the layers (crust and mantle) of the earth also considered a wave Moves rock particles or

4 P Wave/S Wave Graph A graph is sometimes used to determine either the or of seismic waves. These type of graphs help scientists determine where earthquakes. Seismic Waves Surface Waves Travel only through the Arrive P and S Waves Almost entirely responsible for the and of an earthquake. types of Surface Waves (see diagram) Focus and Epicenter the point within the earth where the earthquake originates the point on the earth s surface directly above the focus. Determining the Epicenter Scientists use a method called. It takes seismographs to locate the. You must determine the each station is from the earthquake and draw a around each using the distance as the. Where the circles intersect, is the.

5 Measuring Earthquakes measures the strength or magnitude of an earthquake. Numbered from Each increase in magnitude is actually times greater in - than the previous magnitude Measuring Earthquakes Mercalli Scale measures the or severity of an earthquake. Numbered from Describes what you might during an earthquake in addition to the type of destruction. Tsunami A powerful series of generated by an earthquake or landslide. Huge amounts of seawater are. Can travel at an average of in open ocean Can be very destructive to Japan 2011 More than killed Earthquake triggered a giant tsunami were overwhelmed, creating new problems for people in the middle of destruction

6 Earthquake Prediction Currently there is no way to an earthquake. Scientists can identify most likely to experience earthquakes (close to ). seems to have a sixth sense in predicting earthquakes, but that hasn t been scientifically proven. Earthquake Preparedness Emergency Kit Determine a way of with family members Attach to walls and put stuff on bottoms Shelves Get doorways or outside away from buildings are the killers.