SCEC Award Number 13070 View PDF
Proposal Category Individual Proposal (Data Gathering and Products)
Proposal Title SCEC FlexiRAMP
Name Organization
Paul Davis University of California, Los Angeles
Other Participants
SCEC Priorities 2d, 4a, 5a SCEC Groups Seismology, FARM, SDOT
Report Due Date 03/15/2014 Date Report Submitted N/A
Project Abstract
FlexiRAMP uses seismic stations in flexible array mode between earthquakes in geophysically key areas that in the event of a major earthquake can be moved in a RAMP (Rapid Array Mobilization Procedure) to the aftershock zone. To initiate a SCEC FlexiRAMP in the summer of 2012 we began installation of a line of seismic stations across the southern San Andreas Fault augmenting the TremorScope network that is being installed by UC Berkeley centered on Cholame (Fig. 1)
Even though Parkfield was listed in the SCEC IV proposal as a SFSA (Location A in the proposal map 3.12) and the PI installed equipment there, it has been dropped in the revised plan. So we have responded to our last year’s review by the SCEC panel that “The Planning Committee noted that Parkfield is not a SFSA and is too distant from the PIs to be an attractive area to deploy instruments that would be rapidly available for aftershock studies in southern CA. Deployment of the instruments closer to the PIs in order to facilitate rapid deployment following a large earthquake is strongly encouraged. The committee would prefer the science goals associated with the temporary instruments to be better aligned with SCEC goals.”
We have now returned the instruments to UCLA after recording in the Great Valley near Parkfield June 2012 to December 2013 (Figure 1).

In addition, in June 2013 our 50-station broadband seismic array was returned from Peru. Paul Cox and Igor Stubailo have set up an equipment lab to house and test the array. All 50 Quanterra’s and 40 of the 50 Guralp 3T seismometers have been found to be in working order. The remaining 10 3Ts need significant repairs. However 40 instruments are presently available for SCEC FlexiRamp.

We have a SCEC proposal, under consideration, to install these above the Ventura anticline as the flexible array part of SCEC FlexiRAMP. In that the distance is just a few hours from UCLA, and the region is a SCEC SFSA, we have proposed the deployment is in accord with the Panel’s recommendation.

The great Valley experiment has led to a draft publication to be submitted to BSSA that will be submitted shortly. The highlights are included below.
Intellectual Merit One of the more active non-volcanic tremor (NVT) sites in California is at Parkfield where NVT is found beneath the seismogenic zone and the Moho. Important to understanding NVT is what lies beneath the Moho. There is controversy as to whether it is Fallon oceanic crust or mantle lithosphere. We installed seismic stations in its vicinity where UC Berkeley has installed TremorScope. We used receiver functions to show that the Moho lies above mantle lithosphere and that any remnant of the Farallon plate lies deeper.
Broader Impacts The work formed the basis for a MS thesis by Paul Cox, UCLA. Several graduate students participated in the installation and servicing of the stations (Igor Stubailo, Zagid Abatchev, Paul Cox, Jospeh Ramsay). This knowledge is important if the stations are to be used in a RAMP deployment. Understanding NVT is apart of a larger program to understand the nature of faulting and to improve earthquake forecasting.
Exemplary Figure Figure11: Cross section showing the summary of the interpretation. The red bold line is the Oceanic crust of the Monterey micro-plate interpreted from the receiver functions. The blue dotted line is the rectangular box model from the tomography inversion of the Isabella anomaly. Crustal structure is shown in figure 4.1, mantle material is shown in light pink and the 100 km thick blue slab is the interpretation of the Monterey fossil slab.