October 6, 1997; Costa Mesa
Slide 1:
- Crustal Deformation (Group E)
- Ken Hudnut, USGS - chair
- Duncan Agnew, UCSD (SIO-IGPP)
- Andrea Donnellan, JPL
- Yehuda Bock, UCSD (SIO-IGPP)
- Brad Hager, MIT
- Dave Jackson, UCLA
- Ross Stein, USGS
- Bob King, MIT
- Tom Herring, MIT
- Steve Ward, UCSC
- Zheng-kang Shen, UCLA
Slide 2:
- Landers post-seismic
- near field, short time-constant
- Shen et al., Wyatt et al., Wdowinski et al., Massonnet & Thatcher, Peltzer et al., Savage & Svarc
- far field, long time-constant
- Bock et al. (sparse network of continuous GPS stations)
- Need to confirm signal reported by Bock et al.
- Need to obtain denser spatial information
- Need to work up all SCEC campaign data carefully as a continuing collaborative Velocity Map effort
-
NOTE: These next 2 slides were used to illustrate the long wavelength and
long time-constant post-seismic signals reported for both the Landers and
Northridge earthquakes:
Slide 3:
Figure 8 of Bock et al., 1997 (Aug. JGR)
Slide 4:
Figure 3 of Savage et al., pre-print (submitted to GRL)
Slide 5:
- Velocity map project
- Campaign data sets, many SCEC-funded
- Participants in processing & analysis
- Zheng-kang Shen, Li-yu Sung, Dave Jackson; UCLA
- Simon Mclusky, Bob King, Tom Herring; MIT
- Danan Dong, JPL
- Release 1.0 completed one year ago
- 287 station vectors; EDM & GPS; uniform velocity
- Web page release; EOS article (Shen et al.); Science article (Jackson et al.); other papers in progress by various authors
- Release 2.0 in progress
- 361 station vectors; pre- and post-Landers (non-uniform); several large campaigns & continuous mode GPS data added to the solution
-
NOTE: These next slides are from the latest UCLA solution -
postscript files are available on their ftp site
in /pub/zshen/velmap.
Slide 6:
GPS & EDM combination (361 vectors)
Slide 7:
Comparison of Pre- and Post-Landers vectors
Slide 8:
- With SCIGN, why continue with the Velocity Map project?
- Transient signals associated with the Landers and Northridge events have been observed that may provide new insight into temporal variations in strain and stress, possibly related to the modulation of earthquake recurrence
- Improving the velocity map now will only improve input to seismic hazard maps (sooner rather than later)
- Campaign data provide better regional coverage than SCIGN
- Provide an extremely good combined geodetic solution that can be merged with SCIGN results as they mature (SCIGN will build upon an already remarkably precise geodetic data set)
- Future SCEC-funded campaign surveys can add spatial detail (e.g., coseismic & post-seismic deformation outside the densest part of the SCIGN array), can support investigation of specific studies, and would even provide an
independent check on SCIGN results
Slide 9:
- Next phase
- complete Release 2.0
- evaluate details of status and work plan at tonights group meeting
- finish campaign processing, etc.
- complete Release 3.0 by next years annual meeting
- evaluate level of effort for continuation of the velocity map project, surveys, etc.
