This document discusses seismograms and the different types of seismic waves that are recorded, including P waves, S waves, and surface waves. It explains that seismograms amplify and electronically record ground motion from earthquakes, allowing scientists to determine the epicenter location using travel time graphs from multiple seismographs. The document also covers historical intensity and magnitude scales used to describe earthquake size and introduces moment magnitude as the most widely used scale today because it estimates the energy released.

2.  Instrument
that records
earthquake waves.

3.  Modern seismograms amplify and
electronically record ground
motion, producing a trace.

4.  Also
called L waves, are seismic
waves that travel along Earth’s outer
layer.

5.  Push pull waves. Compress and expand
rocks in the direction the wave travels.

6.  Shake particles at right angles to their
direction of travel.

7.  Derived from the amount of
displacement that occurs along the
fault.

8.  A seismogram shows all three types of
seismic waves- surface waves, P
waves, and S waves

9. Travel- time graphs from three or more
seismographs can be used to find exact
location of an earthquake epicenter.

10.  Historically, scientists have used two
different types of measurements to
describe the size of an earthquake-
intensity and magnitude

11.  Moment magnitude is the most widely
used measurement for earthquakes
because it is the only magnitude scale
that estimates the energy released by
earthquakes.