SeisMac

SeisMac is a Mac OS X application that turns your MacBook or MacBook Pro into a seismograph. It accesses your laptop's Sudden Motion Sensor in order to display real-time, three-axis acceleration graphs. Version 3.0 lets you select and export your collected seismic data. The resizable, real-time scrolling display shows an enormous amount of acceleration information. Place your laptop on a table and see the seismic waves from tapping your toe on the floor. Lay your laptop on your chest and see your heartbeat. And of course, if there is a real earthquake, SeisMac will be displaying full seismic information while you drop, cover and hold-on. When running on the MacBook or MacBook Pro, SeisMac has a range of plus or minus two gravities of acceleration, displaying 256 values per gravity, sampled up to five hundred times per second for each axis. SeisMac is also compatible with older Sudden Motion Sensor-equipped iBooks and PowerBooks.


Keypoints:

  • A Mac OS X application that accesses your MacBook or MacBook Pro's Sudden Motion Sensor in order to display real-time, three-axis acceleration graphs.
  • Great for helping students kinesthetically understand seismic data.
  • Data can be exported for later analysis. 

 


Level: Novice

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Related Animations

Animation of the principles of a drum-style horizontal seismograph station that records back- and-forth (N-S, E-W) movement.

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Animation of the principles of a drum-style vertical seismograph station that records up-and-down movement.

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A cow and a tree in this narrated cartoon for fun and to emphasize that seismic waves traveling away from an earthquake occur everywhere, not just at seismic stations A, B, C, and D. A person would feel a large earthquake only at station A near the epicenter. Stations B, C, D, and the cow are too far from the earthquake to feel the seismic waves though sensitive equipment records their arrival.

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This companion to the animation "Four-Station Seismograph network"  shows the arrival of seismic waves through select wave paths through the Earth (P and S waves) and over the surface of the Earth. The movement at distant stations occurs at a microscopic scale. While that doesn't result in noticeable movements of the buildings, the arrivals are recorded on sensitive seismometers.

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A gridded sphere is used to showt: 1) the seismic stations don't need to be lined up longitudinally to create travel-time curves, as they appear in the first animation, and 2) a single station records widely separated earthquakes that plot on the travel-time curves.

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Animation of the principles of a drum-style vertical seismograph station that records up-and-down movement.

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Related Fact-Sheets

Many people associate earthquakes with destruction caused by falling buildings or by the creation of a tsunami. While earthquakes may be associated with destruction in the time frame of human activity, in the evolution of the Earth they signal the geological forces that build our mountains and create our oceans. This fact sheet provides an introduction to the causes of earthquakes.

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Knowing precisely where an earthquake occurred is an important piece of scientific information. It can help seismologists identify and map seismic hazards. It is also a fundamental piece of information necessary for facilitating studies of Earth's internal structures. This fact sheet provides an overview of the S-P process to locate an earthquake.

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A seismograph is a device for measuring the movement of the earth, and consists of a ground-motion detection sensor, called a seismometer, coupled with a recording system. This fact sheet provides an overview of the basic components of a seismometer and physical science principles behind its operation.

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