# Presentation: 460018

## SCEC - EarthScope (PBO)a confluence of interests

- Ken Hudnut
- U. S. Geological Survey, Pasadena

**Notes:**
Thank you for having me here today.  
 tell you about efforts to monitor earthquakes 
Both for Research and to improve our ability to respond

## How can EarthScope (& ANSS) help to further SCEC science goals?

-  Review what we have (SCEC CMM3 & SCIGN)
-  Examine the EarthScope & SCEC proposals
-  PBO 2 workshop mini-proposal process defined configuration - backbone & clusters
-  PBO committees to select sites - to go from general to specific & meet science goals
-  What if something else would be ‘better’?
-  Any suggested changes should go to PBO SC
-  Identify opportunities for synergy
-  Missions & funding levels of agencies and NGO’s
-  Joint development of data products

## SCIGN Data Products*

- 1st Year
-  Combined time
- 	series (1996-2002)
- 3rd Year
-  Real-time earth-
- quake response
- 5th Year
-  Resolve rates on
- 	primary LA basin
- 	faults (and others)

***SCIGN Data Products****

- *NASA grant - Webb, PI

## SCEC Tectonic Geodesy

-  Complete and
- distribute CMM3
- 3rd Year
-  Integrate InSAR
- 	with GPS for
- 	vertical defor-
- 	mation rates
- 5th Year
-  Resolve rate dis-
- crepancies
- between geology
- and geodesy

## Understanding transient deformation

- Temporal & spatial variations do occur:
- Clustering (e.g., Basin & Range, ECSZ, Asia)
- Discrepant geological and geodetic rates
- Sequences involving fault interaction (e.g., Joshua Tree - Landers - Big Bear - Hector Mine; Anatolian system, etc.)
- PBO and SCEC have nearly identical stated scientific goals on this range of related topics

- Courtesy Anke Friedrich

## Understanding fault interaction

- Emerging view of large events as a composite of sub-events or asperities
- Dynamic triggering
- Static triggering
- Important to study analogous events
- Cascading rupture - is there order in the chaos?
- San Andreas fault - continental transform with excellent on-land exposure of ‘creeping to locked’ transition zones, long simple sections, and ample fault zone complexity

- Bayarsayhan et al., 1996
- Kurushin et al., 1998

- 1857 San Andreas

- 1957 Gobi-Altay

## San Andreas fault

- 35 mm/yr slip rate;
- >70% of plate motion
- 1685, 1812, 1857 eq’s
- Big Bend compression
- 1971 Sylmar (M 6.7)
- 1994 Northridge (M 6.7)
- SoCal is now heavily ‘wired’ - need more?
- 150+ BB CISN stations
- 250+ SCIGN stations
- Catalog; SCEC CMM3
- ‘Natural laboratory’
- Likely source of most future ‘Big Ones’

## What is EarthScope?

- Fully open data policy

## What is PBO?

-  Five year build out phase
-  Five year O&M phase
-  Total 10-year operational commitment
-  Six regional offices in Alaska, Pacific NW, Basin & Range, Rocky Mtns, Southern and Northern California
-  Each region has dedicated resources for recon, permitting, installation, maintenance, and data
-  Nominal data set – 30 sec data file downloaded daily
-  Potential data sets
-  1 sec real time
-  5 Hz on-demand
-  Two precise processing centers
-  Two archive/distribution centers

## PBO and SCIGN

-  125 SCIGN stations proposed for support under NSF existing networks proposal (PBO relies on continued existence of SCIGN & diverse matching funds)
-   NSF funded ‘existing arrays’ proposal fully for next 1.5 years - plan & carry out a transition to PBO operations and maintenance by the end of 5 yrs.
-  ~170 new continuous GPS stations; SAF, ECSZ, transition zones (along-strike and with depth)
-  ~64 borehole strainmeters (yellow); 5 long-base laser strainmeters (Salton Trough ECSZ & PKF vicinities)

## For discussion

-  CISN, ANSS, EarthScope, and PBO do not optimally address questions in earthquake source physics (e.g., SCEC FARM workshop topic on co-seismic phenomena); how can plans be modified to help rectify this? Are we too late?
-  How can we measure Dc? Stress heterogeneity?
-  Heaton slip pulses? Need 3D particle motions close to fault (e.g., the San Andreas fault in the Carrizo Plain and Coachella Valley in SoCal - large events ~likely)
-  Need high resolution deformation field for co-seismics to map slip distributions - without InSAR EarthScope is deficient; what else can be done? (Geo-EarthScope to provide high-res imagery)
-  Fall AGU 2003 & SSA 2004 (Palm Springs)