SeisMac turns your Sudden Motion Sensor-equipped laptop into a seismograph - Mac Freeware. SeisMac turns your Sudden Motion Sensor-equipped laptop into a three-axis seismograph. It shows a scrolling chart of the three axes of acceleration, reading two hundred samples per second. 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. Version 2.0 has a number of major improvements that make it into an even more valuable tool for classroom demonstrations of seismic concepts and techniques. 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. SeisMac is also compatible with older Sudden Motion Sensor-equipped iBooks and PowerBooks. SeisMac is free for Mac OS X 10.4 or later. It is compatible with MacBooks and MacBook Pros, as well as Sudden Motion Sensor-equipped PowerBooks and iBooks.