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PBO Level 2 Data. August 2010 UNAVCO, Boulder. Earthscope Data Levels. Level 0 = Digital Counts Level 1 = Geophysical units (linear strain) Level 2 = Processed data. Level 2 Data. Borehole Strainmeter Analysis Center, Socorro, NM Laser Strainmeter Analysis Center Scripps, UCSD.
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PBO Level 2 Data August 2010 UNAVCO, Boulder
Earthscope Data Levels Level 0 = Digital Counts Level 1 = Geophysical units (linear strain) Level 2 = Processed data
Level 2 Data Borehole Strainmeter Analysis Center, Socorro, NM Laser Strainmeter Analysis Center Scripps, UCSD
Level 2 Data Processed BSM data includes: • Gauge, areal and shear strain • Edits • Tidal Correction • Barometric Pressure Correction • Borehole Trend Correction
Processing Steps 1 sps data Decimate, linearize 300s data Remove predicted signals Remove borehole trend, tides, barometric pressure - edits record Edit data
Processing Steps 1 sps data 300s data Decimate, linearize Apply edits 300s data Generate borehole trend, tides, baro corrections Remove predicted signals Remove borehole trend, tides, barometric pressure - Generate areal, shear strain edits record Edit data Level 2 XML
Processing Steps 1 sps data 300s data Decimate, linearize Apply edits 300s data Generate borehole trend, tides, baro corrections Remove predicted signals Remove borehole trend, tides, barometric pressure - Generate areal, shear strain edits record Edit data Level 2 XML
Processed Data Two stages of processing • Routine, weekly processing • Flagging bad data, estimating offset • Updated every 14 days • Three-month processing • Trends and tides recalculated
ut = * R M dt/(1e+8) 1-(dt/1e+8) do/(1e+8) 1-(do/1e+8) dt raw data value at time t R instrument reference gap (0.01 or 0.02 cm) M instrument diameter (0.087 m) Step 1. Convert digital counts to linear strain The linear gauge strain, u, at time t, is calculated with respect to a fixed raw data point (do) .
Step 2. Edit Time Series • Inspect 1-sps strain data • Flag offsets and non-tectonic signals • No data deleted • Use CleanStrain+ to estimate offsets • Edit low frequency barometric data
Step 3. Remove Borehole Trends • Current method • Modeled by fitting a line plus up to two exponentials to gauge data • Recommend • Highpass filter at 90 days • Goals • Transparency and reproducibility
Step 4. Tidal and Barometric Correction • Input linearized edited data to BAYTAP-G • Estimate amplitude and phase of tides • Assume strain change linearly related to barometric pressure change 2. Compute time series correction using SPOTL • Uses output from BAYTAP-G
1 cos20 sin20 1 cos21 sin21 1 cos22 sin22 1 cos23 sin23 g0u0 g1u1 g2u2 g3u3 1-2 C 0 0 0 D 0 0 0 D Enn + Eee Eee - Enn 2Ene = Step 5. Areal and Shear Strain ui linearized gauge readings gi gauge weightings ( currently 1) orientation of gauge counter-clockwise from east C areal scale factor ( currently 1.5) D shear scale factor ( currently 3)
1 cos20 sin20 1 cos21 sin21 1 cos22 sin22 1 cos23 sin23 g0u0 g1u1 g2u2 g3u3 1-2 C 0 0 0 D 0 0 0 D Enn + Eee Eee - Enn 2Ene = Step 5. Areal and Shear Strain ui linearized gauge readings gi gauge weightings ( currently 1) orientation of gauge counter-clockwise from east C areal scale factor ( currently 1.5) D shear scale factor ( currently 3) • Plan to expand to include calibration matrices of Roeloffs, 2010, and Langbein, 201?
Processed Strainmeter Data Processed data are stored in XML format. • XML files are human and machine readable. • Allows description of the data within the file. • Provides reproducibility.
Processed Strainmeter Data PBO strain XML files contain, • General strainmeter information • Sensor information • Processing information • Processed data
Processed Strainmeter Data <bsm_processing> <timeseries_start_date>2005-10-04T00:00:00</timeseries_start_date> <timeseries_end_date>2006-02-09T23:55:00</timeseries_end_date> <linearization> <gage_weightings> <orientation_matrix> <areal_and_shear_factors> <topography> <atm_pressure unit="microstrain_per_millibar"> <tidal_parameters> <detrend_g0 > <detrend_g1 > <detrend_g2 > <detrend_g3 > <decimate_by_two_filter> <decimate_by_three_filter> <decimate_by_five_filter> </bsm_processing>
Level 2 Data • Full XML files archived at NCEDC and the DMC • Flat ASCII version of most recent processed data set available from UNAVCO
Level 2 Data Files named B018.YYYY.bsm.level2.tar (enables download via cron)
Level 2 ASCII Data OR, use FTP ftp ftp://bsm.unavco.org/pub/bsm/level2/delphi018bor2006/ B018.2010.bsm.level2.tar .
Level 2 ASCII Data To untar the file tar -xf B018.2010.bsm.level2.tar ls B018.2010.bsm.level2 B018.2010.xml.gauge0 B018.2010.xml.gauge1 B018.2010.xml.gauge2 B018.2010.xml.gauge3 B018.2010.xml.2Ene B018.2010.xml.Eee-Enn B018.2010.xml.Eee+Enn
Level 2 XML Data • Example of FTP XML download ftp ftp://www.ncedc.org/pub/pbo/strain/processed/bsm/ delphi018bor2006/2010/B018.2010.xml.bz2
Level 2 XML Data • The program rdstrain.pl will convert the XML file to flat ASCII • Available from the PBO BSM Documentation Page
Level 2 XML Data rdstrain.pl -f B018.2010.xml -o a -s 20100801000000 -e 20100803000000 • B018.2010.xml.gauge0 • B018.2010.xml.gauge1 • B018.2010.xml.gauge2 • B018.2010.xml.gauge3 • B018.2010.xml.2Ene • B018.2010.xml.Eee-Enn • B018.2010.xml.Eee+Enn
Level 2 XML Data • If you just want the processing information use script read_xml.csh • read_xml.csh B018.2010.xml • produces B018.2010.xml.process.txt
Level 2 XML Data cat B018.2010.xml.process.txt B018.2010.xml Wed Aug 25 22:16:44 MDT 2010 delphi018bwa2006 Latitude 46.9795 Longitude -123.0203 Elevation 10.0 m Manufacturer Scalefactor, 0.1 nanostrain per ditigal count CH0 Orientation recorded in field, degrees East of North 267.0 Areal Scale Factor 1.5 Shear Scale Factor 3.0 Detrend Parameters CH0 -13.5 +18.181 -0.0054 -0.0063 0.0 0.0 CH1 -7.83 +8.227 -0.005 +0.0004 0.0 0.0 CH2 7.18 -9.186 -0.0021 +0.008 0.0 0.0 CH3 -23.64 +28.083 -0.003 -0.022 0.0 0.0 Gauge Barometric_Response(ns/millibar) CH0 -3.6 CH1 -5.1
Suggestions • State data windows used to estimate tides • State date at which curing signal is finished • Provide calibration options e.g., • isotropic, Roloeffs 2010