Slide 10
Typical
results from the magnetometer, as shown here as a composite of the 'before'
and 'after' spectrum. In
this instance, the spectrum analyzer was set for 0 to 30 Hz.
The region from about 2 to 5 Hz is seen to be elevated by as much as a 7 dB over the quiet levels of April 10th. The elevated signal region was also observed to be "fluctuating rapidly".
The region from about 2 to 5 Hz is seen to be elevated by as much as a 7 dB over the quiet levels of April 10th. The elevated signal region was also observed to be "fluctuating rapidly".
The signal diminished after about 90 minutes, and was essentially gone after about one day.
Sensor
was located at the La Posta station, East of San Diego, and about 200 miles from the Upland epicenter.
The vertically-oriented search coil was found to be the more sensitive to the geophysical signals, whereas the North-South oriented coil was more sensitive to the Schumann modes.