Appendix_1_PQLX-OF10-1292_1.pdf

PQLX: A Seismic Data Quality Control System Description, Applications, and Users Manual

By Daniel E. McNamara and Richard I. Boaz

Open-File Report 2010–1292

U.S. Department of the Interior U.S. Geological Survey ii

U.S. Department of the Interior KEN SALAZAR, Secretary

U.S. Geological Survey Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2011

For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1-

888-ASK-USGS

For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod

To order this and other USGS information products, visit http://store.usgs.gov

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S.

Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report.

Suggested citation:

McNamara, D.E., and Boaz, R.I., 2011, PQLX: A seismic data quality control system description, applications, and users manual: U.S. Geological Survey Open-File Report 2010–1292, 41 p.

iii

Contents Introduction

Server-Side Analysis

Client GUI Application—PQLX

Trace Viewer

PDF Viewer

STN Viewer

Quality Control Applications

Application at the USGS NEIC

Steps Toward Automation

Future Development

Where To Get It

System Requirements

Development Philosophy, History, and Acknowledgments

References Cited

Appendix

Figures

1. A sample Trace Viewer Split Screen Tab

2. The nine-panel PDF Viewer Main Tab

3. The PDF Detail Tab

4. The Main Tab of the STN Viewer, metadata information, quality control information, and

PSD PDF of the data

5. PDF examples using the Advanced National Seismic System (ANSS) backbone station US.

ERPA–BHZ in Erie, Pennsylvania

6. An example of a common excursion from the station baseline due to the re-centering of the

Streckeisen STS2 seismometer at the ANSS backbone station US.LRAL iv

Conversion Factors Inch/Pound to SI

Multiply By To obtain

Length inch (in.) 2.54 centimeter (cm) inch (in.) 25.4 millimeter (mm) foot (ft) 0.3048 meter (m) mile (mi) 1.609 kilometer (km) mile, nautical (nmi) 1.852 kilometer (km) yard (yd) 0.9144 meter (m)

Area acre 4,047 square meter (m2) acre 0.4047 hectare (ha) acre 0.4047 square hectometer (hm2) acre 0.004047 square kilometer (km2) square foot (ft2) 929.0 square centimeter (cm2) square foot (ft2) 0.09290 square meter (m2) square inch (in2) 6.452 square centimeter (cm2) section (640 acres or 1 square mile)

259.0 square hectometer (hm2) square mile (mi2) 259.0 hectare (ha) square mile (mi2) 2.590 square kilometer (km2)

Volume barrel (bbl), (petroleum, 1 barrel=42 gal)

0.1590 cubic meter (m3) ounce, fluid (fl. oz) 0.02957 liter (L) pint (pt) 0.4732 liter (L) quart (qt) 0.9464 liter (L) gallon (gal) 3.785 liter (L) gallon (gal) 0.003785 cubic meter (m3) gallon (gal) 3.785 cubic decimeter (dm3) million gallons (Mgal) 3,785 cubic meter (m3) cubic inch (in3) 16.39 cubic centimeter (cm3) cubic inch (in3) 0.01639 cubic decimeter (dm3) cubic inch (in3) 0.01639 liter (L) v cubic foot (ft3) 28.32 cubic decimeter (dm3) cubic foot (ft3) 0.02832 cubic meter (m3) cubic yard (yd3) 0.7646 cubic meter (m3) cubic mile (mi3) 4.168 cubic kilometer (km3) acre-foot (acre-ft) 1,233 cubic meter (m3) acre-foot (acre-ft) 0.001233 cubic hectometer (hm3)

Flow rate acre-foot per day (acre-ft/d) 0.01427 cubic meter per second (m3/s) acre-foot per year (acre-ft/yr) 1,233 cubic meter per year (m3/yr) acre-foot per year (acre-ft/yr) 0.001233 cubic hectometer per year (hm3/yr) foot per second (ft/s) 0.3048 meter per second (m/s) foot per minute (ft/min) 0.3048 meter per minute (m/min) foot per hour (ft/hr) 0.3048 meter per hour (m/hr) foot per day (ft/d) 0.3048 meter per day (m/d) foot per year (ft/yr) 0.3048 meter per year (m/yr) cubic foot per second (ft3/s) 0.02832 cubic meter per second

(m3/s) cubic foot per second per square mile [(ft3/s)/mi2]

0.01093 cubic meter per second per square kilometer [(m3/s)/km2] cubic foot per day (ft3/d) 0.02832 cubic meter per day (m3/d) gallon per minute (gal/min) 0.06309 liter per second (L/s) gallon per day (gal/d) 0.003785 cubic meter per day (m3/d) gallon per day per square mile [(gal/d)/mi2]

0.001461 cubic meter per day per square kilometer [(m3/d)/km2] million gallons per day (Mgal/d)

0.04381 cubic meter per second (m3/s) million gallons per day per square mile [(Mgal/d)/mi2]

1,461 cubic meter per day per square kilometer [(m3/d)/km2] inch per hour (in/h) 0 .0254 meter per hour (m/h) inch per year (in/yr) 25.4 millimeter per year

(mm/yr) mile per hour (mi/h) 1.609 kilometer per hour (km/h) vi

Mass ounce, avoirdupois (oz) 28.35 gram (g) pound, avoirdupois (lb) 0.4536 kilogram (kg) ton, short (2,000 lb) 0.9072 megagram (Mg) ton, long (2,240 lb) 1.016 megagram (Mg) ton per day (ton/d) 0.9072 metric ton per day ton per day (ton/d) 0.9072 megagram per day (Mg/d) ton per day per square mile [(ton/d)/mi2]

0.3503 megagram per day per square kilometer [(Mg/d)/km2] ton per year (ton/yr) 0.9072 megagram per year (Mg/yr) ton per year (ton/yr) 0.9072 metric ton per year Pressure atmosphere, standard (atm) 101.3 kilopascal (kPa) bar 100 kilopascal (kPa) inch of mercury at 60ºF (in Hg) 3.377 kilopascal (kPa) pound-force per square inch (lbf/in2)

6.895 kilopascal (kPa) pound per square foot (lb/ft2) 0.04788 kilopascal (kPa) pound per square inch (lb/in2) 6.895 kilopascal (kPa)

Density pound per cubic foot (lb/ft3) 16.02 kilogram per cubic meter (kg/m3) pound per cubic foot (lb/ft3) 0.01602 gram per cubic centimeter (g/cm3)

Energy kilowatthour (kWh) 3,600,000 joule (J) Radioactivity picocurie per liter (pCi/L) 0.037 becquerel per liter (Bq/L) Specific capacity gallon per minute per foot [(gal/min)/ft)]

0.2070 liter per second per meter [(L/s)/m]

Hydraulic conductivity foot per day (ft/d) 0.3048 meter per day (m/d) Hydraulic gradient foot per mile (ft/mi) 0.1894 meter per kilometer vii

(m/km) Transmissivity* foot squared per day (ft2/d) 0.09290 meter squared per day (m2/d)

Application rate pounds per acre per year [(lb/acre)/yr]

1.121 kilograms per hectare per year [(kg/ha)/yr]

Leakance foot per day per foot [(ft/d)/ft] 1 meter per day per meter inch per year per foot [(in/yr)/ft] 83.33 millimeter per year per meter [(mm/yr)/m]

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:

°C=(°F-32)/1.8

Vertical coordinate information is referenced to the insert datum name (and abbreviation) here for instance, “North

American Vertical Datum of 1988 (NAVD 88).”

Horizontal coordinate information is referenced to the insert datum name (and abbreviation) here for instance, “North American Datum of 1983 (NAD 83).”

Altitude, as used in this report, refers to distance above the vertical datum.

*Transmissivity: The standard unit for transmissivity is cubic foot per day per square foot times foot of aquifer thickness [(ft3/d)/ft2]ft. In this report, the mathematically reduced form, foot squared per day (ft2/d), is used for convenience.

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (µS/cm at 25 °C).

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) or micrograms per liter (µg/L).

NOTE TO USGS USERS: Use of hectare (ha) as an alternative name for square hectometer (hm2) is restricted to the measurement of small land or water areas. Use of liter (L) as a special name for cubic decimeter (dm3) is restricted to the measurement of liquids and gases. No prefix other than milli should be used with liter. Metric ton (t) as a name for megagram (Mg) should be restricted to commercial usage, and no prefixes should be used with it.

viii

SI to Inch/Pound Multiply By To obtain

Length centimeter (cm) 0.3937 inch (in.)

millimeter (mm) 0.03937 inch (in.)

meter (m) 3.281 foot (ft) kilometer (km) 0.6214 mile (mi) kilometer (km) 0.5400 mile, nautical (nmi) meter (m) 1.094 yard (yd)

Area square meter (m2) 0.0002471 acre hectare (ha) 2.471 acre square hectometer (hm2) 2.471 acre square kilometer (km2) 247.1 acre square centimeter (cm2) 0.001076 square foot (ft2) square meter (m2) 10.76 square foot (ft2) square centimeter (cm2) 0.1550 square inch (ft2) square hectometer (hm2) 0.003861 section (640 acres or 1 square mile) hectare (ha) 0.003861 square mile (mi2) square kilometer (km2) 0.3861 square mile (mi2)

Volume cubic meter (m3) 6.290 barrel (petroleum, 1 barrel = 42 gal) liter (L) 33.82 ounce, fluid (fl. oz) liter (L) 2.113 pint (pt) liter (L) 1.057 quart (qt) liter (L) 0.2642 gallon (gal) cubic meter (m3) 264.2 gallon (gal) cubic decimeter (dm3) 0.2642 gallon (gal) cubic meter (m3) 0.0002642 million gallons (Mgal) cubic centimeter (cm3) 0.06102 cubic inch (in3) cubic decimeter (dm3) 61.02 cubic inch (in3) liter (L) 61.02 cubic inch (in3) cubic decimeter (dm3) 0.03531 cubic foot (ft3) cubic meter (m3) 35.31 cubic foot (ft3) cubic meter (m3) 1.308 cubic yard (yd3) ix cubic kilometer (km3) 0.2399 cubic mile (mi3) cubic meter (m3) 0.0008107 acre-foot (acre-ft) cubic hectometer (hm3) 810.7 acre-foot (acre-ft)

Flow rate cubic meter per second (m3/s) 70.07 acre-foot per day (acre-ft/d) cubic meter per year (m3/yr) 0.000811 acre-foot per year (acre-ft/yr) cubic hectometer per year (hm3/yr)

811.03 acre-foot per year (acre-ft/yr) meter per second (m/s) 3.281 foot per second (ft/s) meter per minute (m/min) 3.281 foot per minute (ft/min) meter per hour (m/hr) 3.281 foot per hour (ft/hr) meter per day (m/d) 3.281 foot per day (ft/d) meter per year (m/yr) 3.281 foot per year ft/yr) cubic meter per second (m3/s) 35.31 cubic foot per second (ft3/s) cubic meter per second per square kilometer [(m3/s)/km2]

91.49 cubic foot per second per square mile [(ft3/s)/mi2] cubic meter per day (m3/d) 35.31 cubic foot per day (ft3/d) liter per second (L/s) 15.85 gallon per minute (gal/min) cubic meter per day (m3/d) 264.2 gallon per day (gal/d) cubic meter per day per square kilometer [(m3/d)/km2]

684.28 gallon per day per square mile [(gal/d)/mi2] cubic meter per second (m3/s) 22.83 million gallons per day (Mgal/d) cubic meter per day per square kilometer [(m3/d)/km2]

0.0006844 million gallons per day per square mile [(Mgal/d)/mi2] cubic meter per hour (m3/h) 39.37 inch per hour (in/h) millimeter per year (mm/yr) 0.03937 inch per year (in/yr) kilometer per hour (km/h) 0.6214 mile per hour (mi/h)

Mass gram (g) 0.03527 ounce, avoirdupois (oz) kilogram (kg) 2.205 pound avoirdupois (lb) megagram (Mg) 1.102 ton, short (2,000 lb) megagram (Mg) 0.9842 ton, long (2,240 lb) metric ton per day 1.102 ton per day (ton/d) megagram per day (Mg/d) 1.102 ton per day (ton/d) megagram per day per square kilometer [(Mg/d)/km2]

2.8547 ton per day per square mile [(ton/d)/mi2] x megagram per year (Mg/yr) 1.102 ton per year (ton/yr) metric ton per year 1.102 ton per year (ton/yr)

Pressure kilopascal (kPa) 0.009869 atmosphere, standard (atm) kilopascal (kPa) 0.01 bar kilopascal (kPa) 0.2961 inch of mercury at 60°F (in Hg) kilopascal (kPa) 0.1450 pound-force per inch (lbf/in) kilopascal (kPa) 20.88 pound per square foot (lb/ft2) kilopascal (kPa) 0.1450 pound per square inch (lb/ft2)

Density kilogram per cubic meter (kg/m3)

0.06242 pound per cubic foot (lb/ft3) gram per cubic centimeter (g/cm3)

62.4220 pound per cubic foot (lb/ft3)

Energy joule (J) 0.0000002 kilowatthour (kWh) Radioactivity becquerel per liter (Bq/L) 27.027 picocurie per liter (pCi/L) Specific capacity liter per second per meter [(L/s)/m]

4.831 gallon per minute per foot [(gal/min)/ft]

Hydraulic conductivity meter per day (m/d) 3.281 foot per day (ft/d) Hydraulic gradient meter per kilometer (m/km) 5.27983 foot per mile (ft/mi) Transmissivity* meter squared per day (m2/d) 10.76 foot squared per day (ft2/d) Application rate kilograms per hectare per year [(kg/ha)/yr]

0.8921 pounds per acre per year [(lb/acre)/yr]

Leakance meter per day per meter [(m/d)/m]

1 foot per day per foot [(ft/d)/ft] millimeter per year per meter [(mm/yr)/m]

0.012 inch per year per foot [(in/yr)/ft] xi

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:

°C=(°F-32)/1.8

Vertical coordinate information is referenced to the insert datum name (and abbreviation) here, for instance, “North

American Vertical Datum of 1988 (NAVD 88)”

Horizontal coordinate information is referenced to the insert datum name (and abbreviation) here, for instance, “North American Datum of 1983 (NAD 83)”

Altitude, as used in this report, refers to distance above the vertical datum.

*Transmissivity: The standard unit for transmissivity is cubic foot per day per square foot times foot of aquifer thickness [(ft3/d)/ft2]ft. In this report, the mathematically reduced form, foot squared per day (ft2/d), is used for convenience.

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (µS/cm at 25°C).

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) or micrograms per liter (µg/L).

NOTE TO USGS USERS: Use of hectare (ha) as an alternative name for square hectometer (hm2) is restricted to the measurement of small land or water areas. Use of liter (L) as a special name for cubic decimeter (dm3) is restricted to the measurement of liquids and gases. No prefix other than milli should be used with liter. Metric ton (t) as a name for megagram (Mg) should be restricted to commercial usage, and no prefixes should be used with it.

PQLX: A Seismic Data Quality Control System Description, Applications, and Users Manual

By Daniel E. McNamara and Richard I. Boaz

Introduction We present a detailed description and users manual for a new tool to evaluate seismic station performance and characteristics by providing quick and easy transitions between visualizations of the frequency and time domains. The software is based on the probability density functions (PDF) of power spectral densities

(PSD) (McNamara and Buland, 2004) and builds on the original development of the PDF stand-alone software system (McNamara and Boaz, 2005) and the seismological data viewer application PQL (IRIS-PASSCAL Quick

Look) and PQLII (available through the IRIS PASSCAL program: http://www.passcal.nmt.edu/content/pql-ii-program-viewing-data). With PQLX (PQL eXtended), computed PSDs are stored in a MySQL database, allowing a user to access specific time periods of PSDs (PDF subsets) and time series segments through a GUI-driven interface. The power of the method and software lies in the fact that there is no need to screen the data for system transients, earthquakes, or general data artifacts, because they map into a background probability level. In fact, examination of artifacts related to station operation and episodic cultural noise allow us to estimate both the overall station quality and a baseline level of Earth noise at each site. The output of this analysis tool is useful for both operational and scientific applications. Operationally, it is useful for characterizing the current and past performance of existing broadband stations, for conducting tests on potential new seismic station locations, for evaluating station baseline noise levels (McNamara and others, 2009), for detecting problems with the recording system or sensors, and for evaluating the overall quality of data and metadata. Scientifically, the tool allows for mining of PSDs for investigations on the evolution of seismic noise (for example, Aster and others, 2008; and

Aster and others, 2010) and other phenomena. Currently, PQLX is operational at several organizations including the USGS National Earthquake Information Center (NEIC), the USGS Albuquerque Seismological Laboratory

(ASL), and the Incorporated Research Institutions in Seismology (IRIS) Data Management Center (DMC) for http://www.passcal.nmt.edu/content/pql-ii-program-viewing-data� http://www.passcal.nmt.edu/content/pql-ii-program-viewing-data� station monitoring and instrument response quality control. The PQLX system is available to the community at large through the U.S. Geological Survey (USGS) (http://ehpm-earthquake.wr.usgs.gov/research/software/pqlx.php) and IRIS (http://www.iris.edu/software/pqlx). Also provided is a fully searchable website for bug reporting and enhancement requests (http://wush.net/bugzilla/PQLX).

The first part of this document aims to describe and illustrate some of the features and capabilities of the software. The second part of this document is a detailed users manual that covers installation procedures, system requirements, operations, bug reporting, and software components (Appendix).

Server-Side Analysis The PQLX server-analysis program processes data files and stores these results in a user-specified database. The server can be executed either directly from a command line or automated via cron. The system auto-detects and handles the following seismic data formats: Raw Reftek (RT100), mini-SEED, AH, SEGY, SAC, DR100, and NANO. The system is scalable from individual small installations (such as a temporary array) to very large and permanent datasets (multiple networks containing > 8,000 real-time channels).

All data channels “discovered” by the server process are processed with all header information (start time, length, sample rate, and so forth), and location of gaps and overlaps (mini-SEED format only) stored in the database. In addition, channels may be configured for PSD analysis using the method of McNamara and Buland

(2004)

Deconvolution of the trace data for PSD analysis is computed using the RESP file output from the SEED format processing program rdseed (available from the IRIS DMC:

http://www.iris.edu/software/downloads/rdseed_request.htm), used as input to evalresp()

(http://www.iris.edu/manuals/evalresp.htm); deconvolution also includes any digital filters. Various PSD parameters are configurable by the user including window length, maximum period bound, and minimum and maximum power bounds. By a simple addition to a database table, the user has the ability to define, in generic terms, which channels (following a specific naming convention, for example, BH*) should be analyzed using a specific configuration. For example, a single database may define two different PSD configurations for BH http://ehpm-earthquake.wr.usgs.gov/research/software/pqlx.php� http://ehpm-earthquake.wr.usgs.gov/research/software/pqlx.php� http://www.iris.edu/software/pqlx� http://wush.net/bugzilla/PQLX� channels and LH channels. The system is configured to analyze the following channel groups: LH, BH, BL, HG, HN, HL, BH, BN, HH, SH, EH, and EP.

The server also allows the user to import (via XML) other types of data for use by the client GUI. This includes seismic event information (such as an event catalog), as well as metadata information for each channel

(such as name, location, latitude, longitude, instrument type, and sensitivity).

The client GUI program, pqlx, provides a tool to view the processed data. It can connect to the database for visualization and client query of the analysis results. It is within the GUI application that most uses and features of the PQLX system are found.

Client GUI Application—PQLX Building upon the framework of PQL and PQL II, the client-side GUI can connect to either a local database (located on the same machine) or a remote server, either LAN-based or WAN-based (including Internet-wide). This data visualization application is responsible for displaying all graphics of the PQLX system, and is separated into three tools: the Trace Viewer (the original PQL), the PDF Viewer, and the STN (station) Viewer.

Each provides for different viewing capabilities of seismological data and contributes individually and collectively to the task of data quality control.

Trace Viewer The Trace Viewer allows for display of waveform data read in by physical file. It provides for the magnification of traces, including multiple zooming options, spectral analysis of selected data, viewing of each of these data views in split screen mode simultaneously, as well as display of all header values (fig. 1). (Use of the

Trace Viewer does not require a connection to a PQLX database. Indeed, a stand-alone version of PQL is delivered with the PQLX system.) Since all viewers are contained in the same application, pqlx, the Trace Viewer can be invoked from both PDF and STN viewers.

Figure 1. A sample Trace Viewer Split Screen Tab displaying three complete traces, a magnified portion, and the spectral transformation of this magnified portion.

PDF Viewer After connecting to a database, the PDF Viewer allows for display of various types of PDFs based on the previously computed PSD data. Either System PDFs held on the database, or PDF's based on user-provided date and time parameters (a PDF of all PSDs for the month of June over all years of data held) can be requested for display. The main display tab has nine panels and renders System PDFs in various combinations: by station (three different PDFs for a chosen channel group of a single station), by PDF (three different stations for a chosen channel group of a chosen PDF), by both (three different PDFs for three different channels), or as a list (a list of chosen channels of a chosen PDF) (fig. 2).

Figure 2. The nine-panel PDF Viewer Main Tab with the following selections defined by the sidebar controls: all

PSDs held on the database (System PDF All) channels BHZ and LHZ for all stations in the database.

Clicking on any PDF on display in the Main Tab will take the PDF to the Detail Tab of the PDF Viewer for further analysis. This data view allows a user to select a specified portion of the PDF; this “sub-select” is defined as either a single point or bounding box. Once specified, three additional views are displayed: a PDF of all PSDs intersecting through the point or bounding box, a histogram displaying start and stop times of all PSDs

(X-axis = day of year, Y-axis = hour of day), and a view of the first 15 PSD source traces (fig. 3). In addition, mouse-clicking on the lower left panel PDF makes this the new main Detail PDF for further sub-selection in the frequency domain. Mouse-clicking on the trace panel takes the user to the trace viewer for in-depth inspection of the PSD source traces in the time domain. The traces are retrieved from the disk location where data files have been saved, or if the files are not available on the local machine disk then they can be retrieved from a CWB server where they have been stored, if the corresponding IP address and port have been provided and put in the

“Detail” section of the “Controls” panel.

Figure 3. The PDF Detail Tab. The upper left panel displays System PDF All with a sub-select bounding box.

The lower left panel displays the resultant PDF of PSDs intersecting the bounding box defined between periods of 9.3 to 25.8 seconds, and -85 to -103 dB (large earthquakes). The lower right panel is a histogram displaying the start times of the intersecting PSDs. The upper right panel displays the source traces for the intersecting PSDs, here containing the large earthquakes.

STN Viewer The third display is the STN Viewer, organizing the display of trace data by station and channel. Fully configurable, it allows the user to specify which stations and channels should be viewed (traversed as a list), how many days of data should be rendered (between 1 and 60), how many lines to display per page, as well as whether the data should be drawn as actual data, or simply rendered as a horizontal line indicating that data exists. This last option allows the user to check for the existence of data (as well as gaps and overlaps) via a connection to a database while not having access to the waveforms themselves (Fig. 4).

Figure 4A. The Main Tab of the STN Viewer displaying two stations of data, displayed channels filtered using

"[BL]H*" (that is, all BH and LH channels), for one week.

Hovering over the channel label displays a pop-up providing channel metadata information previously imported by the server (fig. 4b).

Figure 4B. Metadata information.

Hovering over the 'Stats' text for each channel displays a pop-up providing statistical quality control (QC) information such as start and end dates, total number of traces, total gaps and overlaps, and maximum and minimum values (fig. 4c).

Figure 4C. Quality control information.

Hovering over the 'PDF' text displays a pop-up displaying the PDF of the data on display and with an additional click takes the user to the PDF Viewer Detail Tab for investigation (fig. 4d).

Figure 4D. PSD PDF of the data.

Quality Control Applications PQLX can be used to explore problems with seismological data, including data gaps and overlaps, instrument-based anomalies, metadata quality, and local noise sources. Historical datasets can be assessed for overall quality, thus increasing the confidence of scientific results. Operators of real-time seismic networks can also benefit from the PQLX system as it allows near real-time analysis and response to data and telemetry problems.

Application at the USGS NEIC The USGS NEIC receives over 4,500 channels of seismic data from over 500 global seismic stations in real time. For many contributed stations, calibration information is not well known. In addition, instrumentation upgrades or changes occur, making it difficult to maintain accurate and timely metadata. The use of real-time seismic data requires automated QC tools to ensure the accuracy of NEIC real-time earthquake products.

Currently, the NEIC computes PSDs for all incoming channels using the PQLX software system on a daily basis.

In order to identify out-of-nominal noise conditions, such as instrument response changes or systems transients, we visually compare the short-term PDFs against the long-term station noise baselines. This method is very sensitive to instrument response inaccuracies (fig. 5).

Figure 5. PDF examples using the Advanced National Seismic System (ANSS) backbone station US.ERPA.--

.BHZ in Erie, Pennsylvania. (a) An incorrect instrument response has been applied to 213 hours of data, during

2008:101 to 2008:106, in order to demonstrate the sensitivity of this method to a possible error in instrument response units. In this example, units of acceleration instead of velocity, expressed as an extra zero in the response file, results in counter-clockwise rotation of the PDF. This is clearly observed as low power at short-periods and high power at long-periods, relative to the long-term station baseline model. In contrast, when a zero is added to the instrument response it results in a counter-clockwise rotation of the PSDs. (b) When an incorrect sensitivity of several orders of magnitude too large is applied to US.ERPA.--.BHZ it results in an over-correction of the data and PSDs are well below the station baseline and NLNM.

Steps Toward Automation In a system under development at the NEIC, hourly PSDs are compared to the long-term station baselines

(McNamara and others, 2009). If the hourly PSD does not fall within the bounds of the station baseline, it is flagged as "out of nominal" and then compared to a set of station-specific noise source models. An effort has begun to characterize station-specific noise source models in an attempt to more precisely monitor a station's state of health. "Out of nominal" noise conditions currently monitored include (1) calibration pulses, (2) missing data,

(3) spikes, and (4) mass re-centers. Once these noise models are defined, the server will be able to compare analysis results as they are created with the noise models and, if within (or without) the noise model bounds, will flag this portion of the trace as having breached the noise model in question. A message screen within the GUI will alert the user to the existence of this breach/flag (fig. 6).

Figure 6. An example of a common excursion from the station baseline due to the re-centering of the Streckeisen

STS2 seismometer at the ANSS backbone station US.LRAL. Using the PQLX software, an analyst can select groups of similar PSDs (fig. 6a), define a noise-source model by storing the characteristic maximum and minimum (fig. 6b), and also view the time series segments through the client interface in order to determine the source and characteristics of the noise excursion (fig. 6c). These steps allow the user to visually define the spectral characteristics of known system transients for comparison against the long-term station baselines. In the prototype-automated system, when an hourly PSD falls outside of the long-term station baseline, it is then compared to the set of known noise-source models for that channel. If a match of at least 75% occurs, a noise-source detection is declared, stored, and ultimately compiled in a report for further investigation by the analyst, system developers, and operations managers.

Future Development PQLX continues to be a work in progress. Additional forthcoming development includes:

• Control of server execution, database and general system administration via the GUI client, pqlx

• Analysis of strong motion data

• Ability to make movies from a series of PDFs over time

• Automated report generation and notification based on user defined QC parameters

• Overlay additional statistics on PDF, for example 90th and 10th percentiles, median, mode, and so forth.

• User defined PSD processing parameters (window length, overlap).

Where To Get It PQLX has been designed to be easily implemented. Fully open-source, easy to compile and implement, and self-configuring based on the existence of data, it allows the network operator and seismologist to concentrate their time and energies on what is important (what the data are trying to tell them).

Source code for PQLX is freely available for download via WWW from:

Download From: http://wush.net/svn/PQLX/tars

Login Username: PQLXtars http://wush.net/svn/PQLX/tars�

Login Password: getPQLX

This site can be accessed both through the USGS:

http://ehpm-earthquake.wr.usgs.gov/research/software/pqlx.php and IRIS:

http://www.iris.edu/software/pqlx .

Also provided is a fully searchable website for bug reporting and enhancement requests; this can be found at http://wush.net/bugzilla/PQLX. For additional information including the PQLX installation and operations manual and PDF interpretation and method details see http://geohazards.cr.usgs.gov/staffweb/mcnamara/Software/PQLX.html.

If you would like to be added to the PQLX mailing list, and be automatically informed of availability of future updates, please email Richard Boaz at ivor.boaz@gmail.com.

System Requirements

Compilation and installation of the entire system happens with a single command and has been demonstrated to work under the following operating systems: LINUX (multiple flavors, including 64-bit architecture), MAC OS X, and Solaris. Portability has been a primary concern, as such, porting to additional systems is likely possible with little effort.

Development Philosophy, History, and Acknowledgments The PQLX software system has been (and continues to be) developed based on open-source software and is itself open-source (licensed under the GNU GPL, version 2). The overall design provides an architectural framework that is intended to be expandable in the future for inclusion of additional functionality as needed, for ease of use (both for end-user and technical maintainer), and for ease of software maintenance. The system comprises both contributed software and original development.

New development in the current release includes database design, server-side analysis program, client-side user interface, PDF image rendering program (to .png format), and data extraction API shell scripts, among others. All original development is provided by Richard Boaz with additional software contributions provided by:

• MySQL - the server-side database holding all analysis results

• GTK+ - the graphical user interface library used to render the client-side GUI, named pqlx.

http://ehpm-earthquake.wr.usgs.gov/research/software/pqlx.php� http://www.iris.edu/software/pqlx� http://wush.net/bugzilla/PQLX� http://wush.net/bugzilla/PQLX� http://wush.net/bugzilla/PQLX� http://geohazards.cr.usgs.gov/staffweb/mcnamara/Software/PQLX.html� mailto:ivor.boaz@gmail.com�

• FFTW3 - the Fourier Transform library, provided by MIT (incorporated by Pete Lombard of the Berkely

Seismological Laboratory)

• gdbm - the GNU database interface holding all client-side user information

• libmseed - a mini-SEED data format file reader library, provided by IRIS DMS

• evalresp - a SEED Response File reader, provided by ISTI

• vfbb - a DR100 data format file reader library, provided by the USGS

• Michael Aramini - High Resolution Bi-Cubic Spline Interpolator, used to render PDF images real-time

PQLX has been developed with major support and funding from the United States Geological Survey, IRIS, and the National Science Foundation. Finally, the authors would like to thank A. Ringler, S. Rastin and L.

Gee for thoughtful comments that improved the presentation of this material.

References Cited

Aster, R., McNamara, D., Bromirski, P., 2008, Multi-decadal climate-induced oceanic microseism variability:

Seismo. Res. Lett., 79, 2.

Aster, R.C., McNamara, D.E. and Bromirski, P., 2010, Global trends in extremal microseism intensity: Geophys.

Res. Lett., 37, L14303, doi:10.1029/2010GL043472.

McNamara, D.E., Hutt, C.R., Gee, L.S., Benz, H.M., and Buland, R.P., 2009, A method to establish seismic noise baselines for automated station assessment: Seismo. Res. Lett., 80, 628-637.

McNamara, D. E., Boaz, R.I., 2005, Seismic noise analysis system, power spectral density probability density function: standalone softare package: United States Geological Survey Open File Report, 2005-1438, 30p.

McNamara, D.E., and Buland, R.P., 2004, Ambient noise levels in the continental United States: Bull. Seism.

Soc. Am., 94, 4, 1517-1527.

http://pubs.usgs.gov/of/2005/1438/� http://pubs.usgs.gov/of/2005/1438/�

Appendix PQLX System Installation and Configuration

Introduction

This document describes all setup dependencies, requirements, and actions necessary to create a PQLX server instance, database(s), and the client-side GUI programs. Please read the entire document before proceeding with the installation as this will provide all the background necessary to get a system up and running in a successful manner.

The PQLX system will compile and execute on any of the following three platforms:

LINUX

Mac OS Solaris

Setup of the PQLX server and system is generally defined to comprise the following actions:

• Server-side technical environment setup, performed once per server machine instance;

• PQLX software compilation and installation, executed once per platform the PQLX server and client will run on, for both server- and client-side programs; and

• PQLX database definition and creation, executed once for each database required.

Server-Side Technical Setup

Server-side technical environment setup comprises the following individual steps:

• Installation of MySQL database server

The database employed to support the PDF database is MySQL (at http://www.mysql.org); it is open-source and fully supported. Download the latest version of the MySQL Community Edition (being certain to download the version necessary for development) and install to the machine designated to be the PDF-PQLX server (typically downloadable from http://www.mysql.org/downloads/, minimum version = 5.0.18).

This may be installed on either a true server machine (on a network with clients connecting from other machines), a stand-alone installation (server and client to reside on the same machine), or both. From a technical standpoint as regards the MySQL database installation, there are no differences between these possible configurations.

Once the database has been installed, start the server (as per platform-specific instructions, using the mysqld_safe script form) and confirm success through execution of the mysql client access program. See installation and startup notes of MySQL for details. As well, consider automating the MySQL server execution on system startup (see platform-specific instructions with the MySQL documentation set), otherwise, the MySQL server will be required to be manually started each time the server machine is booted.

One common problem with the MySQL installation is that the default destination directory for MySQL databases may not be large enough. For reasonably large datasets, the required amount of disk space will also be correspondingly large. Be certain to confirm at time of installation that the directory MySQL will use for its databases is located on a file mount that is ultimately large enough for PQLX usage.

PQLX Software Installation, Compilation, and Production Setup

Installation and configuration of the PQLX system is composed of the following steps:

http://www.mysql.com/� http://www.mysql.org/downloads/�

Satisfy all prerequisites Compile the system Install all executables to production directories Initialize the server database for PQLX usage

Download the latest version of the available source code tar-ball. Decompress and de-tar to the destination directory of choice.

Compilation Pre-Requisites

MySQL

Once the installation of the MySQL server has completed, two environment variables must be set up prior to system compilation. The two entries contained in the file $PQLX/env/mysql.vars define the following MySQL-specifc environment variables:

MYSQLBIN - should be set to the bin directory of the MySQL installation; subsequently used during system execution.

(This will be the directory containing the MYSQL server named mysqld_safe.)

MYSQLINC - should be set to the include directory for MySQL; subsequently used only for system compilation.

(This will be the directory containing the MYSQL file named mysql.h.)

For Solaris implementations, the LD_RUN_PATH variable (set at beginning of env/makeVars file) must include both the PQL GTK+ libraries directory (defaults to PASSCAL installation, change if this path is not valid), and the directory containing the MySQL libraries, please modify accordingly.

It is intended that the modifications made to the file env/mysql.vars be saved in a separate location by the compiling user for subsequent use in future complications of the system. This way, when a new release of the PQLX software is made available, this file can be copied into the PQLX/env directory immediately prior to compilation, alleviating the need to make these modifications by hand each time.

GTK+

A local GTK+ installation must exist on the compiling machine; this can be achieved in one of two ways. It is possible that the minimum version of GTK+ is already installed on the machine. To check if this is the case, execute the following command:

sh> pkg-config --modversion gtk+-2.0

If this returns a version greater than or equal to 2.6.7, then the GTK+ requirement is already satisfied for this machine; you may skip to the next section Compilation.

If there is no version of GTK+ installed or the version installed does not satisfy the minimum requirement, a development version of GTK+ can be installed by downloading and installing the latest version of PQL II as this download also provides for a complete installation of GTK+. The download of PQL II is available from the PQL II Download Page.

Once GTK+ has been installed, verify that the program pkg-config exists in the $PATH environment variable of the compiling user.

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Compilation

Compilation is carried out through the following steps:

Define the installation directory where the PQLX system will be held on disk.

Add the following two lines to the login .rc script (for example, ~/.bashrc) for the executing user of the compilation:

export PQLX=PQLX-install-directory-fullpath source ${PQLX}/env/makeVars

Confirm the directories have been properly defined for the MySQL installation in the file $PQLX/env/mysql.vars detailed above.

Source the .rc file modified in step 2, or open a new window.

In the uppermost PQLX installation directory, compile all source code:

sh> cd $PQLX sh> env/makeALL

The compilation and installation will verify success. If not, a message will indicate which programs are missing (failed) and the name of the log file containing the compilation output to be consulted for investigation.

If the verification fails, the named logfile contains all compiler and linker output messages. As the PQLX system comprises many diverse components, the relevant error message(s) will be located in the logfile in the specific section of each component. The verification message, when indicating failure, will indicate which specific components (libraries and/or executables) are missing. Use this message to position yourself correctly in the ouput logfile to determine the nature of the failure.

Sever-Only Compilation

In the case where it is not desired to compile the client GUI programs on the server (if, for example, the GTK+ libraries are not easily provided for the server platform and/or the client is simply not necessary to be compiled for the server platform), it is also possible to compile only server-side programs.

In this case, follow all procedures as laid out in the section Compilation, including an additional compilation argument to env/makeAll:

sh> env/makeALL srvr

Executed in this manner, no client GUI programs will be compiled, thus requiring no GTK+ graphics files (includes and libraries) be resident on the target server machine.

Installation

Upon successful compilation, the $PQLXPROD sub-directories will contain all files required for PDF server and PQLX system execution. Once compilation is complete, the $PQLXPROD directory may be copied to another directory designated for production execution purposes.

All users who wish to execute any portion of PQLX, either server- or client-side, will require their .bashrc file to source the file PQLXprodVars thus:

export PQLX=PQLX-production-directory-fullpath source ${PQLX}/PQLXprodVars

The file PQLXprodVars defines the following environment variables, each required for execution of PQLX and its various components in a production environment:

export PQLXPROD=${PQLX} export PQLXLOG=${PQLXPROD}/log export PQLXBIN=${PQLXPROD}/bin/${PQLXARCH} export PQLXDBDEF=${PQLXPROD}/dbdef

Once compilation and installation has been completed successfully, the MySQL database is ready for PQLX initialization and usage. Please see document PQLX-DB-Setup.pdf for details.

Subsequent updates/upgrades to the system can be made by compiling the release in question, followed by copying the PROD directory and subdirectories to the local production directory system. It is important that this be a copy operation since there are files generated and installed once the PQLXsystem is initialized with initPQLXdb.sh.

If ever the $PQLXPROD directory structure is overwritten, one file must be regenerated in order for the system to be able to do its work:

$PQLXBIN/mysqlRoot.pw – this file should contain the root password for the MYSQL installation supporting PQLX. If the database initialization specified a PQLX-only install, then the password is PqLXRooT (case sensitive!). Otherwise, this password is defined locally and must be provided to this file.

For example, to recreate using the PQLX-defined root password:

sh> echo 'PqLXRooT' >$PQLXBIN/mysqlRoot.pw

Client/GUI Installation

As for the server, once compilation succeeds, the $PQLXBIN directory will contain all executables to execute the PQLX client GUI programs. To install this on a client machine, the following steps must be carried out for each machine (instructions for each are detailed above):

Verify if GTK+ is already installed and is minimum version required (2.6.7).

If not, install PQL from the PASSCAL download web page.

Install client programs pqlx, pql, and pqlxPNG to directory of choice, making certain this directory is included in the user's PATH environment variable.

PQLX System Files

The following tables detail the binary and script executables, as well as support files currently making up the PQLX system:

Server-Specific Files Description

$(PQLXBIN)/initPQLXdb.sh bash shell script - initializes MySQL for PQLX usage, executed once per MySQL server instance.

$(PQLXBIN)/re-initPQLXdb.sh bash shell script - re-initializes MySQL for PQLX usage, executed only when wanting to delete ALL currently defined databases. Use this command with extreme caution, ALL PDF/PQLX databases are deleted by this command!

$(PQLXBIN)/makePQLXdb.sh bash shell script - creates a PQLX database instance, executed once per PQLX database instance.

$(PQLXBIN)/delPQLXdb.sh bash shell script - deletes a PQLX database instance, executing user must provide PDF database password provided in PQLX database definition File.

$(PQLXBIN)/pqlxSrvr binary executable - PDF-PQLX server program

$(PQLXBIN)/pqlxSrvr_safe bash shell script - executes pqlxSrvr, guarantees pqlxSrvr will complete all tasks in the event queue, that is, pqlxSrvr will restart if it crashes

$(PQLXBIN)/pqlxSrvr_quit bash shell script - shuts down the pqlxSrvr process, both the executable and script

$(PQLXBIN)/importPDFdata binary executable – imports PSDs computed as part of the the PDF Stand-Alone system, version 1.

$(PQLXBIN)/pqlxDBMaint binary executable – perform database maintenance on a PQLX database.

$(PQLXBIN)/rePSD bash shell script – re-execute PSD analyses for a given channel and time range.

$(PQLXBIN)/updatePQLXdb.sh Re-read contents of $PQLXDBDEF (PQLX database definition) file and update to the PQLX database.

$(PQLXBIN)/addDataDirectory.sh Add a data directory to be scanned to a PQLX database.

$(PQLXBIN)/delChannel.sh Remove a specified channel completely from a PQLX database.

Client-Specific Files Description

$(PQLXBIN)/pql binary executable - PQL II

$(PQLXBIN)/pqlx binary executable - PQL-eXtended - PQL II - Waveform Viewer PDF Viewer/Analyzer STN (station) Viewer/Analyzer

$(PQLXBIN)/pqlxPNG binary executable – produce PNG versions of PDF plots

$(PQLXBIN)/exFREQS bash shell executable – return list of PSD frequencies for a given channel

$(PQLXBIN)/exPDFfreq bash shell executable – return a PDF for a given date range and frequency range

$(PQLXBIN)/exPDFhour bash shell executable – return a PDF for a given channel and time and month range

$(PQLXBIN)/exPSDhour bash shell executable – return PSDs for a given channel and date and time range

Support Files Description

$(PQLXPROD)/dbdef/PQLXdb.template.pqlx text file - template file used for defining a PQLX database

$(PQLXPROD)/dbdef/sql/initPQLXdb.sql SQL referenced by initPQLXdb.sh script.

Responsible for setting the PQLX database users in MySQL.

$(PQLXPROD)/dbdef/sql/makePQLXMETAd b.sql

SQL referenced by initPQLXdb.sh script.

Responsible for creating the PQLXMETA database.

$(PQLXPROD)/dbdef/sql/makePQLXdb.sql SQL referenced by makePQLXdb.sh.

Responsible for creating a PQLX database instance.

PDF/PQLX Server Database Setup

Introduction

Before creating a new PQLX Server Database, some preparatory actions must be carried out:

Define which channels will be contained in a single PQLX Server Database Define the location of all PQLX Server-related data Define which channels, if any, should be imported from a previously executed PDF standalone system Define the PQLX Server Definition File

Data Preparation

The PQLX system is driven off the existence of data. For each PQLX database instance, one or more directories are required to be set up containing a mix of either trace files or response files for the channels whose analysis is to be held by the database.

Decide for each PQLX database which channels (or stations) data should be grouped together in a single database. Subsquent client-side queries will be limited to comparisons of data contained within this single database during any given client connection with the server.

There are no requirements as to filenames or directory structures, configuration is left entirely up to the system administrator. All trace and response files may be located under a single directory structure or may be segregated between numerous directories; how this is managed is completely left to the implementor.

Waveform Data File Formats

The following list defines the seismological file formats supported and auto-detected by PQLX. Any PQLX data directory for any given data directory may contain any combination of the following seismological trace formats:

• mini-SEED

• SAC

• SEGY

• AH

• DR100

• NANO

Response File Format

Response files must be provided in a single format, namely, the format produced by the program rdseed, (also available via direct download from the IRIS website). (This format is used for all trace file formats, not just mini- SEED. For non-mini-SEED trace file formats, modify a mini-SEED response file, providing the appropriate values for the channel in question.)

Reponse file requirements are:

• Each response file must contain information for only a single channel.

• Each response file must contain response information for a single channel over all time. That is, a single channel may not use multiple response file instances to represent responses for different time periods.

If after executing the server, no PSD data is generated, the response file is the most likely culprit. Confirm that the response file adheres to the format described here and start again.

Data Set Preparation

Before creating and initializing a PQLX database, the following decisions must be made:

Decide how proposed channels should be segregated by database, that is, decide which channels should be contained within the same database instance.

For each PQLX database, set up one or more directories containing all PQLX-related files per database, trace files, and response files.