March 25, 2004 IRIS Seismometer Workshop1 Testing & Testing Facilities – charge to breakout group nWho/where are current testing facilities? Do we need more? nFacility design – minimum requirements nHow to test new designs (e.g. SCG, laser designs, digital seismometers, etc) nWhat is required to upgrade test facilities to support new designs? nPolicies for test facility use and data access nSupport for test facilities

March 25, 2004 IRIS Seismometer Workshop2 Current test facilities nSandia FACT site nASL - USGS nPinon Flat Observatory - UCSD nPinedale Seismic Research Facility - AFTAC nManufacturers nStations nVarious others –Black Forest Observatory in Germany –Conrad Observatorium in Austria –etc

March 25, 2004 IRIS Seismometer Workshop3 Current test facilities nDo we need more? –Group favors upgrading ASL and Pinyon Flat (PFO) facilities as needed »ASL has granite tunnels & boreholes »PFO is building new, quieter facility –Best chance of getting NSF funding for one or both of these facilities

March 25, 2004 IRIS Seismometer Workshop4 Parameters to be measured (these detemine test facility design req.) nSensitivity & transfer function nSelf noise nBandwidth nClip level nStability of sensitivity & transfer function over time, temperature nCross axis coupling nDynamic range (get from noise & clip level vs. f) nSensitivity to environmental effects –Temperature, pressure, magnetic field variation, RF. Etc nShock (shipping survival)

March 25, 2004 IRIS Seismometer Workshop5 Facility Design – Minimum Requirements nQuiet over all frequency bands of interest nLong term reference seismometers operating nShake table capability nIsolation table (stable table) nTemperature chamber? Use dry ice & John Tsitouris air circulation technique (less expensive) nAuxiliary measurements needed –Pressure, temperature, wind, magnetic, solar –Small seismic array and/or microbarographic array nHigh resolution data acquisition systems + other test equipment nAcoustic absorption on walls to reduce acoustic effects on instruments nCapability to test both vault and borehole dryland instruments (implies vaults/tunnels and boreholes)

March 25, 2004 IRIS Seismometer Workshop6 Facility Infrastructure support nExpert testing personnel nTraining of new testers and users –Education and Outreach component nTest equipment nShipping, storage nElectricity nNetwork connection nPhones nDocumentation (a set of specific tests and results documented in a standard way in a report) nEtc.

March 25, 2004 IRIS Seismometer Workshop7 How to test new designs? nDiscussion centered on what to do with “inherently digital” seismometers in which the analog signal may not be available –For proper coherence noise testing, the samples between channels need to be simultaneous (else noise testing needs to be done on isolation table) –Absolute timing of samples may be an issue –Treat seismometer as “black box” to be tested with available input (ground motion, cal input) and available output (digital or analog) nHow to test Super Conducting Gravity Meters, Laser Interferometer devices not specifically discussed. Characterize as black box (see above).

March 25, 2004 IRIS Seismometer Workshop8 What is required to upgrade existing test facilities to support new designs? nShake tables (both strong and weak motion) nStable tables nHigher resolution digitizers may be necessary if seismometer noise levels go down significantly –Lower voltage rails may also be a problem. –LSB of 24-bit digitizer with 20 V peak full scale is 2.38 microvolts –LSB of 24-bit digitizer with 5 V peak full scale is only 0.6 microvolts –25-bit resolution (or better) may be necessary

March 25, 2004 IRIS Seismometer Workshop9 Policies for test facility use and data access nAccess –Manufacturers and other users should have open access –Test facility operator may need to recover costs for lengthy tests nDevelopment testing may be proprietary, so data will be kept confidential unless permission granted by manufacturer nTest data from commercial off-the-shelf (COTS) seismometers will be made publicly available nData access: Publish on web site and/or appropriate journal (e.g. Seismological Research Letters?) nSecurity –Site security (such as ASL test facility via Kirtland AFB) may be an issue for personnel from foreign countries

March 25, 2004 IRIS Seismometer Workshop10 Support for test facilities nAgency or host organization support –USGS –UCSD nPossible outside funding sources –NSF –NIST –IRIS –AFTAC –Manufacturers? Fees for testing? Try to avoid, if possible, except for lengthy, expensive testing programs. nLong term support? Always an issue.

March 25, 2004 IRIS Seismometer Workshop11 Additional Considerations nProper installation techniques are very important, maybe at least as important as getting a replacement for the STS-1 nWorkshop (at ASL? At UCSD?) to continue Standards for Seismometer Testing (SST) document –Change from “standards” to “guidelines”, add reporting guidelines –Need list of minimum tests to perform for each level of testing (such as Development, Qualification, Acceptance, Operational, Installation) nAbsolute cal technique: Wielandt’s calibration table & software –Table can be purchased from Lennartz or can be built –Software available from Wielandt’s web site: nTests appropriate for field instruments –Temperature, moisture, physical handling, ease of installation –Field test (install in a real or simulated field experiment) nSevere environment testing – test over range specified by manufacturer or by purchaser for special purposes (e.g. Polar use) nTesting during operation –Calibration through cal coil. How often? –Comparison to reference sensor

March 25, 2004 IRIS Seismometer Workshop12 More ideas nStrong motion testing –Tilt: Will instrument continue working properly after experiencing large tilt from local event? –Reproduction of known large displacements (e.g. CalTech pushcart tests of SM velocity instrument) –Clip level –Hysteresis effects nClip level testing in general – all sensors nDifferent types of tests –Development –Design qualification –Acceptance (production units) –Operational –Installation

March 25, 2004 IRIS Seismometer Workshop13 ASL Location on Isleta Reservation

March 25, 2004 IRIS Seismometer Workshop14 ASL Seismometer Test Facilities (Boreholes)

March 25, 2004 IRIS Seismometer Workshop15 ASL Underground Seismometer Test Facility

March 25, 2004 IRIS Seismometer Workshop16 Testing STS-1 Seismometer in ASL underground vault