1. Seismic Instrumentation
Albuquerque Seismological Laboratory Seismometer and Accelerometer Testing Bob Hutt, Adam Ringler, John Evans
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

2. ASL Location on Isleta Reservation near Kirtland AFB
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

3. Seismic Instrumentation
Albuquerque Seismological Laboratory: Originally a Seismometer Test Facility
Seismometer Test Facility
Needed to support the World Wide Standardized Seismograph Network (WWSSN)
Quiet site sought: Low noise at 1 Hz
Nationwide noise survey conducted in 1959
Jim Devine and Joji Tomei
Baby Benioff and photographic drum recorder
Quietest site found was near Grants, NM
Isleta site noise nearly same as Grants site
Isleta site chosen due to proximity of ABQ airport and to minimize dealing with military bureaucracy
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

4. Seismometer and Data Acquisition System Evaluation
Seismometer Evaluation
Dynamic range
Noise (side-by-side comparison in quiet vault or borehole)
Linearity
Clip level
Accurate transfer function determination
Determination of sensitive axis (accurate orientation), cross-axis coupling
Other tests: Described in Hutt, C. R., Evans, J. R., Followill, F., Nigbor, R.L., and Wielandt, E.: Guidelines for Standardized Testing of Broadband Seismometers and Accelerometers, USGS Open File Report
Data Acquisition System Evaluation
Dynamic range, clip level, linearity, sensitivity, crosstalk, common mode rejection, etc.
Cooperation with Sandia National Laboratory
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

5. BB Seismometer noise test
Three BB seismometers on slab with reference instruments
Sleeman 3-sensor (or Holcomb 2-sensor) coherence analysis used to determine instrument noise that is below ambient background noise
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

6. Seismic Instrumentation
Examples of noise of three sensors determined with Sleeman multi-channel coherence analysis
Higher noise example. Higher apparent noise in microseism band caused by imperfect axis alignment between sensors.
Low noise example
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

7. Comparison of Holcomb (2-sensor) to Sleeman (multi-sensor) noise levels
9/23/2018

8. VBB seismometer noise as judged by ability to observe signals
Here, both instruments resolve modes well.
In this case, one instrument (blue) has higher noise than the other in the mode band.
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

9. Noise correlated with atmospheric pressure changes
Top trace is air pressure
Bottom four traces are horizontal long period data from two VBB instruments under test. High correlation with top trace is due to baseplate warping in response to air pressure changes.
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

10. Example of direct noise determination for strong motion accelerometers
Instrument noise of most strong motion sensors is above background noise, so may be observed directly. (Coherence analysis is not required.)
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

11. Example of higher than normal noise from a strong motion instrument
Z component has step offsets
NS component normal
EW component has excessive noise level
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

12. Seismic Instrumentation
Frequency response of VBB instrument by driving calibration coil with random signal
Example of a bad STS-1 response (probably caused by high humidity inside sensor)
Example of a good amplitude & phase response of STS-1
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

13. Mid-band sensitivity verified by comparing response-corrected PSDs
PSD of instrument under test (green) matches reference instruments (blue and red) in 6-second microseism band
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

14. Borehole test facilities: Depths range from 3m to 200m
PVC-cased shallow holes, 3m to 10m, in soil. IRIs-funded, used mainly for testing posthole installation techniques for TA. Two deeper (30m and 60m) steel cased holes in background (in granite).
Allan Sauter working in instrumentation pit near shallow holes.
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

15. Shake tables and step calibration table
Left: Erhard Wielandt checking cross-axis coupling with horizontal shake table.
Below: Erhard using step calibration table (table is his design).
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

16. DC sensitivity of accelerometers determined by box flip test
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

17. Example of results of box flip tests for some MEMS accelerometers
Results are sensitivity, polarity, offset, and orientation of each axis
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

18. Seismic Instrumentation
ASL Test Facilities
Please see Adam Ringler’s poster for more details
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

19. Seismic Instrumentation
Come see us!
ASL’s 50th Anniversary, June 2011
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

20. Seismic Instrumentation
References & Publications See also
Ringler, A. T. and C. R. Hutt (2012). Examples of Guidelines for Seismometer Testing: Weak motion broadband, in prep. Ringler, A. T., C. R. Hutt, and K. Persefield (2012). Seismic station installation orientation errors at ANSS and IRIS/USGS stations, Seis. Res. Lett., in prep. Ringler, A. T., L. S. Gee, B. Marshall, C. R. Hutt, and T. Storm (2012). Data quality of seismic records from the Tohoku, Japan, earthquake as recorded across the Albuquerque Seismological Laboratory networks, Seis. Res. Lett., 83 (3), Ringler, A. T., J. D. Edwards, C. R. Hutt, and F. Shelly (2012). Relative azimuth inversion by way of damped maximum correlation estimates, Comp. and Geosci.,43, 1-6. Ringler, A. T., C. R. Hutt, R. Aster, H. Bolton, L. S. Gee, and T. Strom (2012). Estimating pole-zero errors in GSN-IRIS/USGS network calibration metadata, Bull. Seis. Soc. Amer., 102 (2), Hutt, C. R., J. Peterson, L. Gee, J. Derr, A. Ringler, and D. Wilson (2011). Albuquerque Seismological Laboratory--50 years of global seismology. U.S. Geological Survey Fact Sheet, , 4 p. Ringler, A. T., C. R. Hutt, J. R. Evans, and L. D. Sandoval (2011). A Comparison of seismic instrument self-noise analysis techniques, Bull. Seis. Soc. Amer., 101 (2),
June 10-11, 2013
Seismic Instrumentation
Technology Symposium

21. References & Publications (cont.)
Hutt, C. R. and A. T. Ringler (2011). Some possible causes of and corrections for STS-1 response changes in the Global Seismographic Network, Seis. Res. Lett., 82 (4), Ringler, A. T. and C. R. Hutt (2011). Self-noise models of seismic instruments, Seis. Res. Lett., 81 (6), McNamara, D. E., A. T. Ringler, C. R. Hutt, and L. S. Gee (2011), Seismically observed seiching in the Panama Canal, J. Geophys. Res., 116, B04312, doi: /2010JB Ringler, A. T., L. S. Gee, C. R. Hutt, and D. E. McNamara (2010). Temporal variations in global seismic station ambient noise power levels, Seis. Res. Lett., 81 (4), Evans, J. R., F. Followill, C. R. Hutt, R. P. Kromer, R. L. Nigbor, A. T. Ringler, J. M. Steim, and E. Wielandt (2010). Method for calculating self-noise spectra and operating ranges for seismographic inertial sensors and recorders, Seis. Res. Lett., 81 (4), Hutt, C. R. and A. T. Ringler (2009). Causes and corrections for STS-1 gain changes in the Global Seismographic Network, Eos. Trans. AGU, 90 (52), Fall Meet. Suppl., Abstract S23A Ringler, A. T. and C. R. Hutt (2009). Self-noise models of seismic instruments, Eos. Trans. AGU, 90 (52), Fall Meet. Suppl., Abstract S23A-1736.
June 10-11, 2013
Seismic Instrumentation
Technology Symposium