GRF STATION INSTRUMENTATION
STATION INSTRUMENTATION
DATES OF OPERATION: Start of operation see table above. All stations
operate until present.
SEISMOMETER TYPE:
Streckeisen Model STS-1/VBB. 3-component and 1-component systems
(see list above)
DIGITAL FORMAT
16 bit gain-ranged data words with 11-bit mantissa and 12 gain factors
(132 db dynamic range).
EVENT DETECTOR ALGORITHIM: Multichannel array beam detector
Channel Data: All channels are continuously recorded at 20 Hz sampling rate
Sensitivities
GRA1- BHZ 8.25 e8 Counts/(m/s) @ 1 Hz
GRA1- BHN 8.15 e8 Counts/(m/s) @ 1 Hz
GRA1- BHE 8.03 e8 Counts/(m/s) @ 1 Hz
GRA2- BHZ 8.52 e8 Counts/(m/s) @ 1 Hz
GRA3- BHZ 8.62 e8 Counts/(m/s) @ 1 Hz
GRA4- BHZ 8.83 e8 Counts/(m/s) @ 1 Hz
GRB1- BHZ 8.67 e8 Counts/(m/s) @ 1 Hz
GRB1- BHN 7.77 e8 Counts/(m/s) @ 1 Hz
GRB1- BHE 7.47 e8 Counts/(m/s) @ 1 Hz
GRB2- BHZ 7.85 e8 Counts/(m/s) @ 1 Hz
GRB3- BHZ 9.01 e8 Counts/(m/s) @ 1 Hz
GRB4- BHZ 8.53 e8 Counts/(m/s) @ 1 Hz
GRB5- BHZ 8.29 e8 Counts/(m/s) @ 1 Hz
GRC1- BHZ 8.62 e8 Counts/(m/s) @ 1 Hz
GRC1- BHN 8.48 e8 Counts/(m/s) @ 1 Hz
GRC1- BHE 7.66 e8 Counts/(m/s) @ 1 Hz
GRC2- BHZ 7.86 e8 Counts/(m/s) @ 1 Hz
GRC3- BHZ 7.54 e8 Counts/(m/s) @ 1 Hz
GRC4- BHZ 8.58 e8 Counts/(m/s) @ 1 Hz
Amplitude Response to Ground Velocity:
All stations of the GRF-Array use Streckeisen STS-1 instruments withoutput proportional to ground velocity within a frequency band of approximately 5 Hz to 20 s.
The GRF transfer function T(s) (Laplace transform) is
T(s) = V * N * P(s)
where
(s-z0) * (s-z1) * ... * (s-zN)
P(s) = ------------------------------ (unnormalized poles and
(s-p0) * (s-p1) * ... * (s-pM) zeroes polynomial)
N = 3.0203e10 (normalization of P(s) to 1 at reference frequency 1/(2*pi) Hz)
V = 0.84 Counts/(nm/s) (Sensitivity to ground velocity. This value is a little bit different for each channel at GRF.
The complex poles and zeros are
zeros: (0.0,0.0)
(0.0,0.0)
poles: (-0.2221,0.2221)
(-0.2221,-0.2221)
(-31.4159,0.)
(-7.0058,30.6248)
(-7.0058,-30.6248)
(-19.5721,24.5742)
(-19.5721,-24.5742)
(-28.3058,13.6288)
(-28.3058,-13.6288)
The input to the seismometer is ground velocity. The transfer function for
ground displacement has an additional zero at (0.0,0.0).
Amplitude - Frequency Table of STS-1 (velocity input)
Frequency (Hz) Amplitude (relative) Phase (deg)
1.000000e-02 3.996771e-02 2.846125e+00
1.100000e-02 4.834315e-02 2.815755e+00
1.210000e-02 5.846369e-02 2.782089e+00
1.331000e-02 7.068527e-02 2.744722e+00
1.464100e-02 8.543061e-02 2.703188e+00
1.610510e-02 1.031969e-01 2.656951e+00
1.771561e-02 1.245617e-01 2.605400e+00
1.948717e-02 1.501810e-01 2.547842e+00
2.143589e-02 1.807770e-01 2.483502e+00
2.357948e-02 2.171024e-01 2.411543e+00
2.593743e-02 2.598703e-01 2.331099e+00
2.853117e-02 3.096329e-01 2.241355e+00
3.138429e-02 3.665954e-01 2.141671e+00
3.452272e-02 4.303705e-01 2.031778e+00
3.797499e-02 4.997239e-01 1.912012e+00
4.177249e-02 5.724180e-01 1.783554e+00
4.594974e-02 6.453117e-01 1.648556e+00
5.054472e-02 7.148201e-01 1.510041e+00
5.559919e-02 7.776465e-01 1.371525e+00
6.115911e-02 8.314952e-01 1.236452e+00
6.727502e-02 8.754320e-01 1.107660e+00
7.400253e-02 9.097793e-01 9.870574e-01
8.140278e-02 9.357017e-01 8.755902e-01
8.954306e-02 9.547333e-01 7.733993e-01
9.849737e-02 9.684176e-01 6.800670e-01
1.083471e-01 9.781078e-01 5.948473e-01
1.191818e-01 9.848939e-01 5.168419e-01
1.311000e-01 9.896095e-01 4.451153e-01
1.442100e-01 9.928683e-01 3.787597e-01
1.586310e-01 9.951114e-01 3.169256e-01
1.744941e-01 9.966518e-01 2.588331e-01
1.919436e-01 9.977075e-01 2.037701e-01
2.111379e-01 9.984298e-01 1.510857e-01
2.322517e-01 9.989234e-01 1.001803e-01
2.554769e-01 9.992605e-01 5.049530e-02
2.810246e-01 9.994909e-01 1.503936e-03
3.091270e-01 9.996486e-01 -4.729789e-02
3.400397e-01 9.997560e-01 -9.640011e-02
3.740437e-01 9.998298e-01 -1.462857e-01
4.114481e-01 9.998801e-01 -1.974382e-01
Frequency (Hz) Amplitude (relative) Phase (deg)
4.525929e-01 9.999151e-01 -2.503471e-01
4.978522e-01 9.999391e-01 -3.055159e-01
5.476375e-01 9.999562e-01 -3.634672e-01
6.024012e-01 9.999685e-01 -4.247488e-01
6.626413e-01 9.999773e-01 -4.899425e-01
7.289055e-01 9.999847e-01 -5.596688e-01
8.017961e-01 9.999911e-01 -6.345968e-01
8.819757e-01 9.999970e-01 -7.154530e-01
9.701733e-01 1.000003e+00 -8.030313e-01
1.067191e+00 1.000009e+00 -8.982060e-01
1.173910e+00 1.000016e+00 -1.001948e+00
1.291301e+00 1.000024e+00 -1.115341e+00
1.420431e+00 1.000033e+00 -1.239611e+00
1.562474e+00 1.000043e+00 -1.376151e+00
1.718722e+00 1.000055e+00 -1.526568e+00
1.890594e+00 1.000067e+00 -1.692739e+00
2.079653e+00 1.000080e+00 -1.876895e+00
2.287618e+00 1.000086e+00 -2.081747e+00
2.516380e+00 1.000070e+00 -2.310680e+00
2.768018e+00 9.999750e-01 -2.568093e+00
3.044820e+00 9.995939e-01 -2.859998e+00
3.349303e+00 9.981751e-01 3.088006e+00
3.684233e+00 9.929509e-01 2.695797e+00
4.052656e+00 9.741070e-01 2.224447e+00
4.457922e+00 9.117244e-01 1.644178e+00
4.903714e+00 7.523459e-01 9.493325e-01
5.394086e+00 5.062439e-01 2.270577e-01
5.933495e+00 2.886738e-01 -4.028899e-01
6.526844e+00 1.529730e-01 -9.145214e-01
7.179529e+00 7.920286e-02 -1.334915e+00
7.897482e+00 4.074203e-02 -1.690182e+00
8.687230e+00 2.092073e-02 -1.997050e+00
9.555953e+00 1.073746e-02 -2.265972e+00
Amplitude - Frequency Table of STS-1 (displacement input)
Frequency (Hz) Amplitude (relative) Phase (deg)
1.000000e-02 2.511295e-03 -1.857276e+00
1.100000e-02 3.341305e-03 -1.886748e+00
1.210000e-02 4.444881e-03 -1.919424e+00
1.331000e-02 5.911471e-03 -1.955704e+00
1.464100e-02 7.859100e-03 -1.996042e+00
1.610510e-02 1.044284e-02 -2.040963e+00
1.771561e-02 1.386529e-02 -2.091066e+00
1.948717e-02 1.838876e-02 -2.147032e+00
2.143589e-02 2.434856e-02 -2.209620e+00
2.357948e-02 3.216528e-02 -2.279653e+00
2.593743e-02 4.235181e-02 -2.357977e+00
2.853117e-02 5.550797e-02 -2.445390e+00
3.138429e-02 7.229158e-02 -2.542509e+00
3.452272e-02 9.335465e-02 -2.649582e+00
3.797499e-02 1.192384e-01 -2.766245e+00
4.177249e-02 1.502423e-01 -2.891289e+00
4.594974e-02 1.863121e-01 -3.022533e+00
5.054472e-02 2.270184e-01 3.126268e+00
Frequency (Hz) Amplitude (relative) Phase (deg)
5.559919e-02 2.716684e-01 2.992295e+00
6.115911e-02 3.195283e-01 2.862219e+00
6.727502e-02 3.700536e-01 2.738924e+00
7.400253e-02 4.230298e-01 2.624369e+00
8.140278e-02 4.785916e-01 2.519554e+00
8.954306e-02 5.371584e-01 2.424680e+00
9.849737e-02 5.993433e-01 2.339397e+00
1.083471e-01 6.658744e-01 2.263031e+00
1.191818e-01 7.375438e-01 2.194766e+00
1.311000e-01 8.151826e-01 2.133754e+00
1.442100e-01 8.996536e-01 2.079185e+00
1.586310e-01 9.918548e-01 2.030317e+00
1.744941e-01 1.092729e+00 1.986488e+00
1.919436e-01 1.203274e+00 1.947116e+00
2.111379e-01 1.324560e+00 1.911693e+00
2.322517e-01 1.457736e+00 1.879778e+00
2.554769e-01 1.604051e+00 1.850986e+00
2.810246e-01 1.764862e+00 1.824980e+00
3.091270e-01 1.941653e+00 1.801469e+00
3.400397e-01 2.136047e+00 1.780193e+00
3.740437e-01 2.349823e+00 1.760926e+00
4.114481e-01 2.584934e+00 1.743467e+00
4.525929e-01 2.843524e+00 1.727638e+00
4.978522e-01 3.127947e+00 1.713281e+00
5.476375e-01 3.440797e+00 1.700253e+00
6.024012e-01 3.784916e+00 1.688429e+00
6.626413e-01 4.163437e+00 1.677692e+00
7.289055e-01 4.579803e+00 1.667943e+00
8.017961e-01 5.037800e+00 1.659087e+00
8.819757e-01 5.541594e+00 1.651043e+00
9.701733e-01 6.095762e+00 1.643734e+00
1.067191e+00 6.705345e+00 1.637093e+00
1.173910e+00 7.375884e+00 1.631059e+00
1.291301e+00 8.113477e+00 1.625575e+00
1.420431e+00 8.924828e+00 1.620591e+00
1.562474e+00 9.817313e+00 1.616060e+00
1.718722e+00 1.079904e+01 1.611943e+00
1.890594e+00 1.187895e+01 1.608201e+00
2.079653e+00 1.306685e+01 1.604799e+00
2.287618e+00 1.437353e+01 1.601707e+00
2.516380e+00 1.581088e+01 1.598896e+00
2.768018e+00 1.739197e+01 1.596341e+00
3.044820e+00 1.913117e+01 1.594018e+00
3.349303e+00 2.104429e+01 1.591907e+00
3.684233e+00 2.314872e+01 1.589987e+00
4.052656e+00 2.546360e+01 1.588243e+00
4.457922e+00 2.800995e+01 1.586656e+00
4.903714e+00 3.081095e+01 1.585214e+00
5.394086e+00 3.389204e+01 1.583904e+00
5.933495e+00 3.728125e+01 1.582712e+00
6.526844e+00 4.100937e+01 1.581629e+00
7.179529e+00 4.511031e+01 1.580644e+00
7.897482e+00 4.962134e+01 1.579749e+00
8.687230e+00 5.458348e+01 1.578935e+00
9.555953e+00 6.004182e+01 1.578195e+00