Wells_NV.mov

http://www.iris.edu/hq/waves As seismic waves radiate out from the epicenter of an earthquake and encounter Earth's surface, they cause the ground to move. Unless the earthquake is nearby, the scale of these motions are generally too small, perhaps only .001mm (a fraction of the diameter of a human hair), and occurs over a time scale, 100s of seconds, that is too long for humans to feel or detect. However, sensitive instruments such as seismographs are able to discern such changes and record them as seismograms. In the video nearly 400 seismic stations are represented by a circle on the map. The color of the station indicates the ground displacement at that individual station e.g. red is negative displacement while blue is positive. Viewed together their recordings illustrate the classic Earth science instructional analogy; "Seismic waves radiate outward from an earthquake's epicenter like ripples on water".

Category:

Science & Technology

Tags:

• seismology
• seismic waves
• earthquake