Bulletin of the Seismological Society of America; February 2006; v. 96; no. 1;
p. 237-257; DOI: 10.1785/0120050052
© Seismological Society of America
Click on image to view larger version.
Figure 6. Spectrogram of natural frequencies as observed at MIK, May 2001
through November 2003. Spectrogram composed of 1-hr time windows, each scaled so
maximum is 1 and plotted with linear color bar. Weather data are from JPL
weather station (
= 8.5 km). Vertical breaks in data are due to
days with data glitches or no recorded data. Tick marks on x axis
correspond to first of the month labeled underneath. The peaks in natural
frequencies are observed to wander over the course of the 2.5 years. No
long-term correlation with temperature is observed, though rain causes temporary
lengthening of natural frequency.
