pbo strainmeter products strainmeter short course earthscope meeting may 12, 2009 strainmeter short...

PBO Strainmeter

Products

PBO Strainmeter

ProductsStrainmeter Short Course

Earthscope MeetingMay 12, 2009

Strainmeter Short CourseEarthscope Meeting

May 12, 2009

PBO Web Page

http://pboweb.unavco.orghttp://pboweb.unavco.org

MAPS

PBO Network Map

Strainmeter Homepages

What is recorded at a PBO BSM site?

• Strainmeter

• Seismometer

• Barometer

• Rainfall gauge

• Temperature sensor


• Strainmeter

• Seismometer

• Barometer

• Rainfall gauge

• Temperature sensor

• Tiltmeter

• GPS

• Accelerometer

• Pore pressure sensor


Type Rate (sps) Archive Format Frequency

Strain 201

1/600

Bottle, SEEDBottle, SEEDBottle, SEED, ASCII

HourlyHourlyDaily

Environmental 1/300 Bottle, SEED, ASCII Daily

Barometer 1 SEED Streaming

Seismic 1, 100 SEED Streaming

Pore pressure 1/300 ASCII Daily

Tiltmeter 1 ASCII Daily

Strainmeter Dataflow

• SEED– The data are translated to miniSEED by PBO– Transferred to NCEDC and IRIS DMC via SEEDLink– Data downloaded from logger oh hourly basis

• ASCII– Low frequency bottle data also translated to ASCII and made available from PBO web site

Updated every hour

Updated every day

Strainmeter

Logger

UNAVCO

Convert to mSEED

Collect bottle files

UNAVCO - BSMAC

Monitor dataflow, quality

Track metadata, archiving

Process data

Updated every 2 weeks

The PBO Strainmeter Page

A master list of all PBO strainmeter data sets is displayed on the PBO strainmeter products web page .

http://pboweb.unavco.org/strain_datahttp://pboweb.unavco.org/strain_data

Raw Data: All sample rates

Archived at the DMC and the NCEDC

• SEED format

• Bottle format: 24-hour long files

Raw Data: Low Frequency

UNAVCO provides:

• Bottle format: Long-term merged data

• ASCII format: Long-term merged ASCII data

Processed Data

Processed Strainmeter data

• Gauge, areal and shear strain

• Edits

• Tidal Correction

• Barometeric Pressure Correction

• Borehole Trend Correction

Processed Data

Processing Step Method

1. Decimate, linearize Minimum phase, causal FIR filters

2. Edit & estimate offsets TSVIEW, PIASD (CLEANSTRAIN)

3. Borehole Trends Linear & exponential model

4. Tidal Model BAYTAP-G, PIASD

5. Barometric Response BAYTAP-G, PIASD

6. Areal and shear strain Generated with nominal scale factors

Processing Steps

1 sps data

Decimate,linearize

-

Edit data edits record

Remove predicted signalsRemove borehole trend, tides, barometric pressure

300sdata

Processing Steps

1 sps data

Decimate,linearize

-

Edit data edits record

Remove predicted signalsRemove borehole trend, tides, barometric pressure

300sdata

Apply edits

Generate borehole trend, tides, baro corrections

Generate areal, shear strain

Level 2 XML

300sdata

Two categories of processed data:

• 2a: Rapidly processed data setUpdated every 14 days

• 2b: Post-processed data set Trends and tides recalculated Models updated every 4 months

Processed Strainmeter Data

Step 1. Decimate , Linearize

• SEED and bottle data are in digital counts.

• The linear gauge strain, u, at time t, is calculated with respect to a fixed raw data point (do) .

dt/(1e+8)

1-(dt/1e+8)

do/(1e+8)

1-(do/1e+8)*

R

Mut =

dt raw data value at time tR instrument reference gap (0.01 or 0.02 cm)M instrument diameter (0.087 m)

Step 2. Edit

• Inspection of 100% 1-sps strain data

• Flag signals known to not be tectonic

• Use PIASD to estimate offset - moving to cleanstrain+

• Edit low frequency barometric data

Step 2. Edit

-40000

-30000

-20000

-10000

0

10000

2006/6/1 2006/7/1 2006/8/1 2006/9/1UTC

2. Editing

B007, Shores, WA

Cou

nts

CH0 CH1 CH2 CH3

Step 3. Detrend 2. Editing

Current Method• Trends are modeled by fitting a linear term

plus one to two exponentials to the data

Goals• Transparency• Repeatability

Step 3. Detrend

5

10

15

20

25

150 180 210 240 270 300 330 360 390

CH0

CH1

CH2

CH3

days since install

B087

Nov-14, 2006 July-14, 2007

B087, Ford Ranch, AnzaInstalled June 2006

5

10

15

20

25

150 180 210 240 270 300 330 360 390

CH2

model

ch2=10.758+30.294*exp(-0.00925*t)-0.043*t

Days since install

mic

rost

rain

April 4, 2007

Days since install

mic

rost

rain

Step 3. Detrend

B087, Ford Ranch, Anza

CH2ModelCH2

5

10

15

20

25

150 180 210 240 270 300 330 360 390

CH2

model July 13, 2007

ch2=10.758+30.294*exp(-0.00925*t)-0.043*t

mic

rost

rain

CH2Model

Step 3. Detrend


Days since install

5

10

15

20

25

150 180 210 240 270 300 330 360 390

CH2

model

updated model

ch2=10.758+30.294*exp(-0.00925*t)-0.043*t

ch2=12.519+36.327*exp(-0.00681*t)-0.025*t

Days since install

mic

rost

rain

CH2ModelUpdated Model July 13, 2007

mic

rost

rain

Step 3. Detrend


Days since install

Step 4. Tides

a. Input linearized edited data to BAYTAP-G

- Estimate amplitude and phase of tides

b. Compute time series correction using PIASD

- Uses output from BAYTAP-G

Edited Gauge Data

BAYTAP-G

PIASD

Correction

Step 4. Tides

-0.05

0

0.05

0.1

0.15

0.2

0.25

07-Feb-23 07-Feb-25 07-Feb-27 07-Mar-1 07-Mar-3 07-Mar-5

B081 Keene Wilde Anza-0.05

0

0.05

0.1

0.15

0.2

0.25


Tide removed

mic

rost

rain

B081 Keene Wilde Anza

Step 5. Barometric Correction

• Assume strain change linearly related to

barometric pressure change

• Estimate simultaneously with tides using

BAYTAP-G

Step 5. Barometric Correction

-0.05

0

0.05

0.1

0.15

0.2

0.25


B081 Keene Wilde Anza

Pressure removed

mic

rost

rain

Edited Gauge Data

BAYTAP-G

Response Coefficient

Step 6. Areal and shear strain

ui linearized gauge readingsgi gauge weightings ( currently 1) orientation of gauge counter-clockwise from eastC areal scale factor ( currently 1.5)D shear scale factor ( currently 3)

g0u0

g1u1

g2u2

g3u3

=1-2

1 cos20 sin20

1 cos21 sin21 1 cos22 sin22 1 cos23 sin23

C 0 00 D 00 0 D

Enn + Eee

Enn - Eee

2Een

• Processed data are stored in XML format (ASCII).

• XML files are human and machine readable.

• Allows description of the data within the file.

• Provides reproducibility of the processed data



Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

B004.2007.2008007071250B004.2008.2008020071250

B004.2008.200803671250

B004.2008.200804671250

2007 2008 2a data

2b data



B004.2007.2008007071250B004.2008.2008020071250

B004.2008.200803671250

B004.2008.200804671250

B004.2007.2008061071250

2007 2008 2a data

2b data

2b data



B004.2007.2008007071250B004.2008.2008020071250

B004.2008.200803671250

B004.2008.200804671250

B004.2007.2008061071250B004.2008.2008061071250

B004.2008.2008061241250

B004.2008.2008159121220

B004.2007.2008061151250B004.2008.2008062001250

2007 2008 2a data

2b data

2b data

2b data B004.2008.2008062131432


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>


• The most recent XML file is named BBBB.YYYY.xml.bz2 (enables download via cron)

• Flat ASCII version of most recent processed data set available from UNAVCO

pbo strainmeter products strainmeter short course earthscope meeting may 12, 2009 strainmeter short...

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