Proposals for Consideration by the SCIGN Coordinating Board

SCIGN Coordinating Board Annual Mtg.

by Ken Hudnut; 26 April 2004

High-rate Data (2 Hz)Gulf of California Stations

Proposals for SCIGN CB Consideration

• High-rate data (2 Hz)– Z-12’s can do 2 Hz– Z-12’s ring buffers do

not function properly– Requires technical fix– Low cost PC104

solution with many added benefits

• Memory• TCP/IP• Linux OS

• Gulf of California sites– Limits on uses of the

PBO MREFC funds to within USA mean that Mexico-PBO on hold

– SCIGN-CICESE-UNAVCO partnership at GUAX

– Caltech and Arizona projects & matching

– Enthusiasm to go ahead but need funds

High-rate Data (2 Hz)

• High-rate and Real-time are separate issues• RTK users benefit from real-time 1 Hz data, but do not

require >1 Hz data rate• Scientists would like high-rate data (latency OK); e.g., at

UNAVCO 2004 annual meeting - community said use data buffers to get maximum data rate possible with receivers and memory configuration available (this was similar to the SCIGN decision in 1996) [not real-time]

• Operational need for ‘near-real-time’ high-rate data exists for finite fault source models (e.g., ShakeMap); >1 Hz would be helpful, e.g., 2 Hz from the SCIGN Z-12’s but USGS cannot afford it (without ANSS funding) and many seismologists remain skeptical of relative value

Strong-Motion and GPS• Need a several-pronged approach

to the overall enhancement of ExNets’ GPS and strong-motion equipment to record future large earthquakes’ ground motions more completely

• PBO will not provide all needed near-field stations, nor will USArray - must find another way

• SCIGN should fund upgrades to its own equipment (e.g., high-rate buffers for the Z-12’s)– Strong-motion sensors should

be welcomed at SCIGN stations (doing this - ANSS?)

– Survey-mode GPS ought to be conducted (USGS?)

GPS2 Hz

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1-sec GPS VS. Integrated Strong Motions

Slides courtesy of Dr. Chen Ji, CaltechSSA 2004, Palm Springs

Continuous GPS

Integrated strong motion

Synthetic PGV Map (1-sec)

High-rate Upgrades

• Principles and Policies– Cost-effective and well-tested so as not to lose data

or have other negative impacts on normal operations– In accord with PBO plans for telemetry & data flow

(SCIGN should transition to & adopt their Data Plan)– Outside funds for upgrades go to the SCIGN Network

Administrator (John McRaney) and are then spent as directed by the SCIGN Coordinating Board

• Ramp-up 2-yr. approach recommended– Year 1: $85K to set-up and deploy 75 Vipers high

priority stations along San Andreas, SJF, ECSZ, etc.– Year 2: $68K for remaining 75 sites, as appropriate

Gulf of California Stations• All proposed work is collaborative with Javier Gonzalez

Garcia at CICESE and his colleagues & collaborators• Loading of the PBO region may or may not be steady in

time and space (e.g., Savage, 1971; Press and Allen, 1995; Pollitz et al., 1998); need to test this theory– GUAX established as a check; Gonzalez et al. (2003) velocity is

consistent with plate motion models; now need to maintain continuous GPS into the future to see if it remains constant velocity or not over many years

– Need to extend this across the Gulf, spanning from Baja to Sonora and crossing to check kinematics of deformation established by survey-mode GPS and recent geological studies

• Test stationarity of spatial and temporal deformation within the relatively weak ‘loading’ section of the plate boundary - a must for PBO

From Nicholson et al. 1994 Geology

~12 Ma ~5 Ma

Extension of the Pac-NAm plate boundary into the Gulf of California and the accompanying development of the S. San Andreas fault:

• significantly postdates the ~12 Ma (southward) plate boundary jump

• appears to also postdate the ~8 Ma change in direction of Pac-Nam motion

Slides courtesy of Prof. Joann Stock, CaltechSSA 2004, Palm Springs

From Oskin and Stock(GSAB, 2003)

Other Projects

• NARS-Baja broad-band seismological stations by CICESE, Caltech, and Utrecht

• CICESE joint projects– Bennett et al. NSF– GUAX collaboration

• UNAM & INEGIjoint projects

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Station Selection & Upgrades• Support monument upgrades

at stations identified by Gonzalez and Bennett– Must be built by June 2004– UNAVCO engineers to build

SCIGN SBM’s– Telemetry & receivers OK– NSF funds requested

• Select 4 NARS stations to upgrade with good monuments (SCIGN SBM) and continuous GPS in year 1 (may not be feasible to telemeter data)

• Reconnaissance of additional stations as needed to complete a braced array of 12 sites along the Gulf

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Immediate need $20K

Year 1 - need $30K

Year 2 - need $70K

Proposals for SCIGN CB Consideration

• High-rate data (2 Hz)

– Improve recording of large near-field deformation from large earthquakes

• CGPS to max. rate

• SM at GPS sites

• Static GPS at SM sites

– Support smooth PBO transition with 3G

– Total cost $153K over upcoming 2 years ($85K - yr. 1; $68K - yr. 2)

• Gulf of California sites

– Keep GUAX going– Help Gonzalez and Bennett

with short-term opportunity– Identify NARS sites for

upgrade to CGPS– Select additional sites for

completing 10-12 site array within 2-3 years from now

– Total cost $120K over upcoming 2 years ($50K - yr. 1; $70K - yr. 2)