The images shown here are from continuous recording of a dense network deployed in Sante Fe Springs, CA. The owner of the data is BreitBurn Energy who have provided the data to Caltech. The survey was executed by LA Seismic using the Fairfield Node system. We thanks Henry Biggart of Geokinetics for providing the vibrator source for the survey. The survey was conducted Sept 4 - Sept 29, 2012.
|The red dots are the SFS stations with the main cluster containing approximately 2500 stations. Surrounding the main cluster are 12 outrider stations. The green dots are permanent stations of the SCSN.|
|A movie of the time history of the deployment is available here - Deployment-Movie . In this movie gray dots show undeployed stations, green dots indicate a full hour of data is recovered from the stations, and red dots indicate a partial hour hour of data recovery. The red dots that occur while the survey is in progress generally show the nodes being swapped.|
|Blow up of the stations in the map above. The outrider stations are numbered as the digits on a clock face. Click on a number below to see the results of a virtual source at that position. It takes approximately 4 sec for the surface waves to arrive on the grid.|
Virtual Source Movies With Reciprocity
Each of the outrider sensors are used as a virtual source. Each movie
begins with a travel time plot. Note there was insufficient data for
sensor 2. The red circles on the plots are at 2 km intervals from
the virtual source. Reciprocity is invoked by averaging the positive
and negative side of the correlations.
Virtual Source Movies Without Reciprocity
The same as above, except that the reciprocity averaging is not
done. Note the difference between 3 and 9.
Time-distance plot of correlations for each virtual source
The vertical axis is time, but the horiztonal axis is sensor number,
sorted by distance.
|0.2s   5.0 Hz||0.3s   3.3 Hz||0.4s   2.5 Hz|
|0.5s   2.0 Hz||0.6s   1.7 Hz||0.7s   1.4 Hz|
|0.8s   1.3 Hz||0.9s   1.1 Hz|| |
During the deployment of the Santa Fe Springs array, there were very few earthquake in the vicinity of the network. There was however, a Ml=3.4 earthquake in Berverly Hills (blue star on top map) 35 km from the center of the network on 2012/09/07. This occured during the initial deployment of the sensors so only 60% recorded the event. To see the movie, click here.
Acknowledgements We thank BreitBurn Energy for permission to use the data in this research and to Eric Campbell of LA Seismic for supplying it to us.