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Real-time GPS in Cascadia and its application to hazards reduction. Tim Melbourne Marcelo Santillan Craig Scrivner Walter Szeliga CS481 Team Risc (GPS Cockpit) Frank Webb (JPL) . Pacific Northwest Geodetic Array Dept. of Geological Sciences Central Washington University
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Real-time GPS in Cascadia and its application to hazards reduction • Tim Melbourne • Marcelo Santillan • Craig Scrivner • Walter Szeliga • CS481 Team Risc (GPS Cockpit) • Frank Webb (JPL) Pacific Northwest Geodetic Array Dept. of Geological Sciences Central Washington University www.panga.org Support:NASA ROSES NNH07ZDA001N and USGS NEHRP
Overview 1. (L1) Cascadia real-time GPS Station Network (PANGA + PBO) 2. (L2) GPS processing (phase+psuedorange data -> position estimates) • (L3) EEW products derived from rtGPS position streams • Example earthquakes as examples – 2010 Sierra El Mayor, 2010 Maule, 2011 Tohoku-Oki • GPS Cockpit Project: Managing rtGPS time series and derived products
Seattle M6-7 crustal faults not well known, <1m EEW M8-9: megathrust, <5m EEW
Latency: most data arrives in less than 1 secondPANGA telemetered to CWUPBO telemetered to UNAVCO, then to CWU Arrival at CWU Arrival at Boulder
(L2) Real-time processing strategies Relative Positioning Absolute (Point) Positioning Lower absolute precision (improving) Single station-capable Linear wrt station # Requires rt orbit + clock corrections Requires extensive data editing Higher relative precision Requires stable reference station Requires dense network Primarily commercial RTK
2. PANGA/CWU real-time processing • (1) Relative positioning: Trimble commercial product (joint w/ WSRN and OGRN RTK processing) • (2) Real-time GIPSY Point positioning: • (3) Developing standard GIPSY (not RTG) processing with clock and orbit correction streams from DLR (German Aerospace Center, Munich, Hauschild)
Method 3: CWU short-arc real-time processing with GIPSY Requires clock corrections streamed over Ntrip (DLR, IGS
Method 3: CWU real-time processing with GIPSY -Requires extensive phase-level data QC -Less than 5s latency
~10cm deviations are common in all methods BREW CNCR CHZZ CABL TRND
4. Example Earthquakes 2010 Maule Chile M8.8 Mike Bevis, UNAVCO
2010 Maule: Absolute point positioning of CONZ 2010 Chile M8.8 north 3m east
Absolute vs. relative positioning PBO, relative p., 24+24 hr http://supersites.earthobservations.org/baja.php CWU, pp., 5 minutes http://www.panga.cwu.edu/events/baja/
pgDisplacement- 2010 Sierra El Mayor GPS PGD Seismic PGA
2011 Tohoku-Oki Earthquake GEONET GPS ARRAY
+15s: Seismic Detection JMA: M6.8 NEIC W phase: M9.0 ~20 minutes
GPS Moment Estimate +60s: Mw 8.47
GPS Moment Estimate +90s: Mw 8.80
GPS Moment Estimate +120s: Mw 9.04
GPS Moment Estimate +180s: Mw 9.05
JMA: M6.8 +15s: Seismic Detection NEIC W phase: M9.0 ~20 minutes 60s:M8.5 90s:M8.8 120s:M9.04
-Time Series viewer (interactive): negation of false positives -Data Aggregator (Perl, modular, talk to Craig Scrivner) -Many new derived products: -DefMaps -Inversions -GPS ShakeCast -Assimilation into seismic EEW not obvious 5. GPS Cockpit
GPS Cockpit Slip DefMap
GPS Cockpit GPS Cockpit
GPS Cockpit GPS Cockpit
Conclusions 1. Cascadia has mature real-time GPS networks (PANGA + PBO) • Data analysis is evolving rapidly • EEW products based on rtGPS position streams are also improving • Recent earthquakes show the importance of rtGPS in hazards monitoring • GPS Cockpit: First release on March 15