Ground Motion Prediction Equations for the Central and Eastern United States Using an Integrated Database

Date: 4/25/2019

Time: 06:00 PM

Room: Grand Ballroom

In this study we use an integrated database of recorded events and simulated ground motion to develop a new suite of ground motion prediction equations (GMPEs) for the central and eastern United States (CEUS). For the simulated part of the integrated database, we use an improved two-stage SSGFM. An improved two-stage stochastic summation of Green’s functions method (SSGFM) is a convenient and fast technique to simulate strong ground motion time histories in regions such as the CEUS where detailed information about the faults such as the slip distribution, the geometry of the fault, and the asperity location not known. This procedure stochastically captures the effect of rupture propagation for large earthquakes and the effect of propagation path on seismic waves coming from different parts of the fault. We employ synthetic weak ground motions as input motions into SSGFM because the resulting strong ground motion time histories are region-specific and are constructed based on the seismological characteristics of the CEUS. Thus, they can be used in development of ground motion models for the study region. We simulated weak motions using SMSIM for small earthquakes with M3.5, M4.0, and M4.5. Then, the improved two-stage SSGFM is implemented to simulate synthetic time histories for moment magnitudes of M5.0 to M8.0 in 0.5 increments using the generated weak motions at the JB distance range of 1 to 1000 km. A subset of NGA-East database is then combined with this synthetic database to produce an integrated database for the ground motion model development.

The coefficients of the proposed functional form are determined using a mixed effect regression. We also derive between-event, site-to-site, and event-site corrected aleatory variabilities as well as the total standard deviation. The proposed ground motion model for the CEUS is applicable for magnitudes ranging from 3.5 to 8.0 and JB distances up to 1000 km. The applicable V_S30 for other spectral periods is in the range of 160 to 3000 m/sec.

Presenting Author: Farhad Sedaghati

Authors