SCEC Award Number 14022 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Evaluation of Attenuation Models (Q-Vs Relationships) used in Physics-Based Ground-Motion Earthquake Simulation through Validation with Data and Comparisons with NGA
Name Organization
Ricardo Taborda University of Memphis
Other Participants 1 Graduate Student
SCEC Priorities 6e, 6a, 6c SCEC Groups CME, GMSV, GMP
Report Due Date 03/15/2015 Date Report Submitted N/A
Project Abstract
Durign the course of this project we performed a series of deterministic earthquake ground-motion simulations to assess the influence that different attenuation models have on the quality of the synthetics when these are compared with recorded data. The main objective of the project was to characterize the level of sensitivity of the ground motion to the attenuation relationships. Here, by attenuation relationships we refer to the relationships used to define the quality factor \qs{} as a function of the shear wave velocity \vs{}. To accomplish this we proposed a new and simple \qs{}-\vs{} relationship that is defined in terms of only 3 parameters. This new \qs{}-\vs{} function is sufficiently flexible to allow one to duplicate almost all other relationships used in previous simulations and thus allowed us to conduct a systematic study on the influence of its parameters on the simulation validation results. Our initial results for the case of simulations up to 1 Hz for the 2008 Chino Hills earthquake indicate that it is possible to significantly improve validation goodness-of-fit results with a more appropriate selection of the \qs{}-\vs{} relationship. Further analysis of our results will allow us to propose adequate parameter for other simulations.
Intellectual Merit Initial results from this project provide valuable insight about the choice of appropriate attenuation models for low-frequency simulations. This will help better constrain simulation parameters for simulation efforts at large, but more important, it will help build a more robust set of parameters for SCEC projects such as CyberShkae and High-F. While we are well-aware that material quality factors are frequency and depth dependent, we believe that the results obtained thus far within this project help define a baseline or reference framework that will facilitate further improvements in modeling intrinsic attenuation in anelastic wave propagation simulations. This, in turn, will help advance the use of simulations in engineering applications.
Broader Impacts This project provided direct funds and research opportunities two Ph.D. students at the University of Memphis: Naeem Khoshnevis (Geophysics) and Shima Azizzadeh-Roodpish (Civil Engineering). Both these students are affiliated with the Center for Earthquake Research and Information and work under the supervision of the PI. Initial results obtained for the specific purpose of the project will be presented this year at the 2015 SSA Annual Meeting. Details of the presentation are given in the next section. In addition, training of Khoshnevis toward the execution of the project research resulted in a spin-off research topic on the influence of signal processing (filtering) on the validation of ground motion simulations. Additional presentations on this topic are also listed below.
Exemplary Figure Figure 4