Seismology: the study of earthquakes and seismic waves
Target 9- I can describe a seismograph Seismograph: an instrument that records vibrations in the ground –Measures vertical and horizontal motion of the ground –Records motion on paper and electronically
Seismogram: a tracing of earthquake motion that is recorded by a seismograph –P waves are recorded first –S waves are recorded second
Target 11- I can identify the location of P waves, S waves, and Surface waves on a seismogram
Target 12- I can determine the S-P Interval of a seismogram and use that to calculate the distance to the epicenter To determine the distance to an epicenter, scientists analyze the arrival times of the P waves and the S waves –The more space between the P waves and the S waves, the farther away the earthquake occurred
Magnitude: a measure of the strength of an earthquake –Moment Magnitude Scale: measures an earthquake’s strength based on the size of the area, the amount of movement, and the rigidity, of the fault that moves
Target #14- I can find the amplitude of an earthquake on a seismogram To determine magnitude of an earthquake you must find the amplitude of the S- wave –Amplitude is determined by measuring how high above the center line the tallest S wave is on a seismogram
Target #15- I can use the distance and amplitude found using a seismogram to determine an earthquake’s magnitude What would be the magnitude of an earthquake 100 km away that produced 100 mm of amplitude? What would be the magnitude of an earthquake 60 km away that produced 2 mm of amplitude? What would be the magnitude of an earthquake 200 km away that produced 100 mm of amplitude? What would be the magnitude of an earthquake 500 km away that produced 2 mm of amplitude?