[Shake-dev] amplification on soil sites / MMI bias

[Georgia Cua]

Dear Bruce,

We are now running grind (id 313 2011-01-24).

We've rerun the makeMMItables script.

However, we still have "patchy" intensity maps that look like this. (The "patches" are less pronounced than produced in the previous version of grind, but there are still blue patches at relatively large distances from the epicenter.)

It is still probably that effect that you mentioned before on applying site amplification on intensities? 

Is this what would be expected with the most recent fix, or did you expect that the far-away blue patches would go away completely?

Just for reference, I'm also attaching the mi_regr plot. The intensity bias is -0.83. It is in the right direction now, with the recent fix. Does a bias calculation make sense when the data are essentially on a flat line? (One could still argue for no bias calculation in this case?)

Thanks, and sorry to keep bothering you with these not-felt/weak shaking events!
Georgia 



-----------------------------
Dr. Georgia Cua
Swiss Seismological Service
Institute of Geophysics
ETH Zurich, NO H61
Sonneggstr 5
CH-8092 Zurich
Switzerland

Tel:  +41-44-633-7574   
Fax: +41-44-633-1065   

georgia.cua at sed.ethz.ch
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