Version-3 Seismograms

Undamped oscillations indicate that the period is 3.55 s.  SAC file.

Lift-test calibration pulse.  SAC file.

Helicorder record showing the Mw7.7 P.N.G. event of 9/9/2005.  The AmaSeis display gain is set to 20.

For comparison, an AS1 helicorder record from Sarracino Middle School in New Mexico.  The AmaSeis display gain is set to 60.

The COR broadband helicorder record for the same time interval.

Mw7.7 earthquake in the New Ireland Region of P.N.G. as recorded on the "wooden" seismometer.  A low pass filter with corner at 0.1 Hz has been applied.  SAC file.

In spite of the display gain being 3 times lower on the "wooden" system, the earthquake signal amplitude looks comparable.  The big difference is in the background noise, which is probably an order of magnitude greater on the "wooden" system as compared with the New Mexico AS1 system.  The excess noise is probably due to the poor location of the wooden system, which is on the third floor of a town house in Corvallis. 

I will be moving the system to a better location in late September, 2005, and will make another noise comparison at that time.