The EarthScope USArray Transportable Array: Results from Large-scale Network Operations Bob Woodward, Bob Busby, Katrin Hafner, and David Simpson Incorporated Research Institutions for Seismology (IRIS) CTBT S&T 2011 Conference June 8-10, 2011 Vienna, Austria

Outline Describe the Transportable Array (TA) Performance of the Transportable Array Operational Strategies

The Transportable Array Large scale - 450 broadband stations Transient stations – network configuration changes daily Large investment – high expectations 1,680 sites 19 sta / month 4.5 Gb / day $10M / year 2011 - 2013 Red = current array location Grey = stations already removed

Array & Station Design 400 broadband seismic stations Goals ~70 km spacing ~2000 x 1000 km “footprint” ~2 year deployments at each site 10 years and 1623 sites to roll across the country Goals High-quality broadband data Maximize data return (>85%) Data in near real time 40 and 1 sps continuous

TA Performance Network availability typically exceeds 98% Station noise highly uniform and quite low for temporary installations

Uniformity of Stations Standard vault design Modular communications Vault interface enclosure Encloses everything but the DAS and seismometer Low-power autonomous operation A typical operating TA Station 535A Dale TX Station deployment treated as a high-precision manufacturing operation

Multipart Approach to QC Array Network Facility (network hub) Builds tools and automated processes to gather status, inventory, and operational diagnostics for real-time monitoring Performs picking and associations that occasionally detect waveform issues Data Management Center (archive and distribution) Analysts review all long-period data and catalog subtle changes in character Run automated tools to parameterize certain data qualities All reports go to TA management for integration and action

State-of-Health Review Real-time monitoring of SoH Detect problems Initiate corrective actions Station QC & SoH on the web SoH channel displays Both near-real-time and summary Metrics for arbitrary time intervals Mass position - life of station PDF noise analysis by station-channel Temperature and voltage - life of station From ANF station status web pages From DMC QUACK tool

Web-based Monitoring http://anf.ucsd.edu/tools/webdlmon Identify changes and how they accumulate over time E.g., - in last 24 hours: number of reboots, number of IP changes, number of link cycles E-mail Alerts: Some status changes result in an email alert to distribute more information immediately about the change: Pump active signal, Q330 reboot http://anf.ucsd.edu/tools/webdlmon Monitoring system renders data into actionable format Information then feeds weekly management prioritization for all service activities

Orientation Direct measurement of orientation of all stations Using fiber-optic gyroscope Measures orientation to < 0.2o When station is installed When station is removed Direct measurements validate empirical estimates Empirical orientation estimates from surface and mantle wave polarization techniques As of 2011 - 95.6% of the TA stations have polarization anomalies within +-3 degrees In 2008, this number was 79.9% TA station orientation, relative to north, from empirical analysis Results from Ekström and Busby, SRL, 2008

Calibration Automated process for command, capture, and analysis of cal signals Analysis of calibration signals to verify amplitude and phase response Applied to all TA stations at beginning and end of deployment System wide calibration in 2009

Station Evolution Adding pressure transducers to create a 400 station atmospheric acoustic (infrasound) network Span frequency band from DC to 20 Hz TA Station 345A, MS

EarthScope is funded by the National Science Foundation. Summary 400 station network operating at >98% availability Uniform, autonomous, low-power stations Multipart approach to QC Real time SoH channels Interactive reviews Automatic reviews, short-term and long-term behavior QC feeds actionable information to TA Management Attention to calibration, orientation, and trends in data Careful evolution of stations Info on the Web EarthScope www.earthscope.org USArray www.usarray.org National Science Foundation www.nsf.gov EarthScope is funded by the National Science Foundation. EarthScope is being constructed, operated, and maintained as a collaborative effort with UNAVCO, and IRIS, with contributions from the US Geological Survey, NASA and several other national and international organizations.