Yehuda Bock and Brendan CrowellCecil H. and Ida M. Green Institute of Geophysics and

Planetary PhysicsScripps Institution of Oceanography

La Jolla, California

GPS Early Warning System for S. California

2008 HPWREN Users MeetingPala Native American Reservation

November 19, 2008

California Real Time Network (CRTN)

(http://sopac.ucsd.edu/projects/realtime/)

• Stations span major faults of southern San Andreas fault system

•Raw GPS data streamed over dedicated radio links (including HPWREN) with a latency of a fraction of a second

• Total displacement waveforms are generated independently every second by instantaneous positioning

• 10-20 Hz data rates have been demonstrated

Real Time (Active)

CGPS.

Test Bed for Early Warning Systems

Earthquake Geodesy (coseismic motions)GPS Seismology (dynamic motions)Volcano monitoringStructural monitoringLandslide monitoringTsunami warningFlood Control

2004 Stromboli eruption LA freeway after 1994

Northridge earthquake

Displacement waveforms, 2004 Parkfield event

RTD Server,SOPAC Database,

Web Services, GPS Explorer

SOPAC Utilities

Data

Communications

Data

Network

• SECTOR CGPS Coordinates

• HTDP Crustal Motion Model

• NGS Geoid Model

• Ionosphere Model

• IGS Precise Orbits

• NOAA Troposphere Model

• SOPAC Archive/Metadata

ServerModels

Single-Base RTK User Positioning

Service

Raw DataUser

raw data streams

RTCM (CSRS)

CSRC

GPS Station

CRTN Components

Displacement Waveforms

Troposphere Delays

Imperial Valley Survey – October ‘08

• Three autonomous teams surveyed about 20 geodetic monuments each in 2-3 days

• Two 15-minute occupations of each monument

• Used CRTN Positioning Service to compute ITRF2005 coordinates

• Positions available at the end of each occupation

• Ideal for post-earthquake surveys

http://sopac.ucsd.edu/projects/caltrans_iv2008.html

RTD Server,SOPAC Database,

Web Services, GPS Explorer

SOPAC Utilities

Data

Communications

Data

Network

• SECTOR CGPS Coordinates

• HTDP Crustal Motion Model

• NGS Geoid Model

• Ionosphere Model

• IGS Precise Orbits

• NOAA Troposphere Model

• SOPAC Archive/Metadata

ServerModels

Single-Base RTK User Positioning

Service User

Raw DataUser

raw data streams

NMEA (CSRS)

RTCM (CSRS)

RTCM

GPS Station

CRTN Components

Displacement Waveforms

Troposphere Delays

EWS

Japan’s Geophysical Survey Institute (GSI) operates nationwide 1200-station continuous GPS network (GEONET), with ~ 20 km spacing. Of these, 1156 stations are streaming @ 1 Hz to a central facility in Tsukuba City.

2003 Mw 8.3 Tokachi –Oki earthquake

Triangulation Scheme

• Create a Delaunay triangulation of the network every second

• Compute relative positions of each triangle

• Convert to principal components of strain (2D)

• Establish detection criteria to isolate an event

• Determine an anchor point for computing absolute positions

2003 Mw 8.0 Tokachi –Oki earthquake

Demo

ShakeOut

Total Displacement Waveforms

240˚ 241˚ 242˚ 243˚ 244˚ 245˚ 246˚

31˚

32˚

33˚

34˚

35˚

36˚

37˚240˚ 241˚ 242˚ 243˚ 244˚ 245˚ 246˚

31˚

32˚

33˚

34˚

35˚

36˚

37˚

AZRY

AZU1

BILL

BLSA

CAT2

CCCS

CIT1

CNPPCOTD

CRRS

CSDH

CVHS

DESC

DHLG

DSME

DVLEDVLSDVLWDVNEDVNWDVSEDVSW

DYHS

ESE2ESRW

EWPP

FVPK

GLRS

GMPK

GNPS

HBCOHNPS

HW62IMPS

KYVWLASC

LORS

MAT2MJPK

MLFP

MONP

MVFD

NSSS

OEOC

P066

P472

P473

P474P478

P480

P482

P483

P486

P494P497

P499

P500

P506

P509

P510

P566

P623

PIN1PIN2

PMOB

POTR

PPBF PSAP

RAAP

SACY

SBCC

SCIPSIO5

SKYB

SLMS

TABLTOST

TRAK

UCLP

UCSB

USGC

VDCY

VTIS WHYT

WIDC

1 m

100

100100

100

100

100

100

200

200

200

500

500500

1000

1000

Coseismic Displacement Model

California Spatial Reference Center (CSRC) Proposal for a Statewide California Real Time Network

Multipurpose:• Positioning Service• EWS Test Bed• GPS Meteorology

http://csrc.ucsd.edu/input/csrc/proposals/CRTNProposal_version5.0.pdf