Real Time Data from US East Coast
Nelson-Nordgren, Astatic Spring, Broadband Force Balance, Vertical (FBV) Seismometers

Yuma High Gain Output, Filtered for Distant Events

WinSDR updated every 5 minutes. YDivisor = 1, Filtered 0.002 Hz - 0.07 Hz, 100 samples/sec, Scale = 394 nm/s/line, Ag(hi+) = 28,300 V/m/s, Clip Level = 353 nm/s

Yuma Low Gain Output, filtered for Local Events (high gain/50)

Clip Level = 1.8 cm/s

Period Extended High Gain Output

Yuma period extension to 120 seconds, gain divisor set to 1

The spring constant (N/m) has been measured over a summer to winter temperature cycle to be -245.4 (uN/m)/(N/m)/C, (-245.4 ppm/C). The output velocity error with temperature, with Ri at 15K Ohms, is calculated to be (42.3 um/s)/C/hr. Integrater voltage vs. temperature over the summer to winter time period is 309 mV/C with a total temperature range of 4.7C/year. Daily temperature variations are typically 0.5C or less.