Three Earthquake Tracker sites (ULF monitoring stations), are showing lots of activity near the Bay area. The stations are at Black Point, Crystal Springs, and San Jose. The stations appear to be operating properly, as the 3.5 VRMS calibration spikes look good at all three locations.

For those new to this board, "Earthquake Tracker" is a series of Ultra Low Frequency monitors that were installed at various locations along faults in California. The monitors were installed because Stanford engineers found ULF anomalies prior to the Loma Prieta quake in 1989.

All the best, Billion

• Earthquake Tracker