The EarthScope USArray Transportable Array: Results from Large-scale Network Operations

Bob Woodward, Bob Busby, Katrin Hafner, and David SimpsonIncorporated Research Institutions for Seismology(IRIS)

CTBT S&T 2011 ConferenceJune 8-10, 2011Vienna, 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

Red = current array location

Grey = stations already removed

2011 - 2013

• 400 broadband seismic stations• ~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

Array & Station Design

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

535A Dale TX

A typical operating TA Station

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

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• 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

State-of-Health Review

PDF noise analysis by station-channel

Temperature and voltage - life of station

Mass position - life of station

From ANF station status web pages

From DMC QUACK tool

Web-based Monitoring

• 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

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• 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%

Orientation

TA station orientation, relative to north, from empirical analysisResults from Ekström and Busby, SRL, 2008

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• 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

Calibration

Station Evolution

• Adding pressure transducers to create a 400 station atmospheric acoustic (infrasound) network

• Span frequency band from DC to 20 Hz

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TA Station 345A, MS

• 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

Summary

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.

Info on the Web• EarthScope

www.earthscope.org• USArray

www.usarray.org• National Science Foundation

www.nsf.gov