CyberShake Study 15.12

CyberShake Study 15.10 takes the deterministic results from CyberShake Study 15.4 and adds broadband components.

Initial tests

We performed initial tests by using the Graves code from the current version of the BBP to synthesize stochastic seismograms, along with applying site amplification from CB2014. We used the Vs30 value taken from the same velocity model as the deterministic seismograms (CVM-S 4.26). We also applied site amplification from CB2014 to the deterministic seismograms. Then the deterministic seismograms were low-pass filtered at 1.0 Hz, and the stochastic seismograms were high-pass filtered at 1.0 Hz, and the results were combined. From this broadband seismogram we calculated PSA and RotD values.

Run	10 sec SA	5 sec SA	3 sec SA	2 sec SA	1 sec SA	0.5 sec SA	0.2 sec SA	0.1 sec SA
PAS, broadband (run 4266)
PAS, broadband (run 4266, blue) vs deterministic (run 3878, black)
LADT, broadband (run 4271)
LADT, broadband (run 4271, blue) vs deterministic (run 3870, black)

Sample Seismogram

Below is a seismogram for PAS, source 273, rupture 69, rupture variation 50, comparing the 1 Hz seismogram (blue) to the 10 Hz seismogram (green). Mostly, the 10 Hz seismogram looks sharper.

Deterministic Site Amplification

We ran PAS and LADT with and without deterministic site amplification (using CB 2014, and Vs30 values from CVM-S4.26). Here are the results:

Run	10 sec SA	5 sec SA	3 sec SA	2 sec SA	1 sec SA	0.5 sec SA	0.2 sec SA	0.1 sec SA
PAS, site amplification (run 4266, blue) vs no deterministic site amplification (run 4270, black)
LADT, site amplification (run 4271, blue) vs no deterministic site amplification (run 4272, black)