[Shake-dev] ShakeMap 3.5 Bug in BA08

[Charles (Contractor) Worden]

All,

Thanks to the hard work of our colleague Inchan JEON of Korea, we have found and resolved a bug in the BA08 module in ShakeMap 3.5. This bug affects the amplitudes of small events in particular, so you may wish to review some of your smaller recent events to see the extent of the differences.

This fix is highly recommended (essentially, it’s mandatory if you are using BA08). The fixed code is version 1618 in the repository, but only requires changing one line in BA08.pm, so you may wish to make this change in your source (don’t forget to “make” afterwards to propagate the fix from the src/lib/GMPE directory to the perl/lib directory).

The change to BA08.pm is at line 654:

<          . "SUB $dsc->[c3] MUL ADD EXCH 10 ADD LOG $fb MUL SUB $fa ADD";
---
>          . "SUB $dsc->[c3] MUL ADD EXCH 10 ADD LOG10 $fb MUL $fa EXCH SUB E LOG10 DIV ADD”;

Attached is the revised file. Make sure to remove the “_fixed” when installing.

ShakeMap v4 is unaffected by this issue.

Bruce


C. Bruce Worden
Synergetics Inc. Contractor in support of USGS
Please note that my USGS email address is now:
cbworden at contractor.usgs.gov

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