Site with Default Borehole

QUAKE ADVICE_Select Strong Motion Accelerograms

Generation of Site Specific Earthquake Ground Motion

Users are required to select options of the following:

1. Bedrock motion intensity (k_pZ):

2. Site soil profiles (five choices):

To generate soil surface motions for a default soil profile: click one of the four panels below.

I. Input Parameters:

II. Output Results:

The site-specific spectra presented here are generated following the 4 Routines shown below. More details of each Routine can be found in Ref [1].

Routine 1: The conditional mean spectrum (CMS) is constructed for matching the code spectrum on rock sites at four reference periods (T*) of 0.2s, 0.5s, 1s, and 2s. For each CMS, the controlling magnitude-distance (M-R) combinations are identified first by hazard disaggregation analyses for the seismic intensity defined at the bedrock (refer to Input 1). The results of the controlling M-R combination and the rock shear wave velocity are shown in Table 1.
Routine 2: The CMS is scaled by applying ground motion prediction equations (GMPEs) so that the CMS matches the code spectrum at each of the reference periods.
Routine 3: Accelerograms representing rock outcrop motions conforming to the controlling scenario (refer to Table 1) are extracted from the PEER database. The extracted accelerograms are scaled so that their calculated response spectra match closely with the CMS in the period range of 0.2T* to 2T*. With each CMS, the "best six" accelerograms having the least sum of squares error (SSE) are selected.
Routine 4: Twenty-four accelerograms and response spectra (six from each of the four reference periods) representing motions on the soil surface are obtained by performing equivalent linear analysis of the soil column model (refer to Input 2). The 24 response spectra and accelerograms for the case of primary direction of excitation are shown in Figures 1 and 2 below.

Table 1. The range of magnitude-distance and bedrock shear wave velocity used while sourcing the strong motion database for each reference period (T*).