[CEUS-earthquake-hazards] Article on Central U.S. Earthquake hazard by expert panel

[Susan Hough]

I read and reread the ScienceNOW article looking for the word
"prediction," having seen Rus' comment before I read the article.  Seems
to me clear that Seth was commenting on the reliance on observed
seismicity alone to constrain hazard maps. I'm sure he talked to Kerr at
some length -- as always only a sound-bite makes it into a short article.
Rus' point is well taken: no one earthquake is a "failure" of a hazard
map, unless maybe the earthquake exceeds an Mmax value that was assumed in
generating the map.  More generally, though, I think the main point Seth
was making has been underscored by the quakes he mentioned.  I've made
this exact same argument in my own talks (most recently this evening),
usually by way of making the point that the short historical record can
lull people into a false sense of security.  But clearly it can go the
other way sometimes.  I.e., just thinking conceptually, there must be
areas that have been more active in the historic (or known prehistoric)
record than the average long-term rates.

Sue Hough



> The probabilistic methods that the USGS and other organizations use to
> estimate hazard are not predictions. Instead, the methods give estimates
> of the strength of shaking that we'd expect (at specified odds) to be
> exceeded in the next 50  years at some particular place. The specified
> odds are usually about one in ten or one in fifty. If a particular place
> is shaken at or above the estimated level, the cause could be either a big
> earthquake far away, or a smaller one nearby. Also, the expected shaking
> could occur at any time from tomorrow to 50 years from now...or not at
> all, if it beats the odds. Nothing in a probabilistic hazard estimate
> specifies the size, time, and location of the next big earthquake.
>
> Making a prediction and estimating the hazard are fundamentally different
> in purposes, assumptions, calculations, results, and uses. A failure to
> get either of them right has no bearing on the validity of the other one.
> -----------------------------------------
> Rus Wheeler
> research geologist
> phone: (303) 273-8589
> fax: (303) 273-8600
> email: wheeler at usgs.gov
>
> paper mail:
> Russell L. Wheeler
> U.S. Geological Survey
> P.O. Box 25046, M.S. 966
> Lakewood, CO 80225
>
> physical address, FedEx, UPS:
> 1711 Illinois St., rm. 442
> Golden, CO 80401
>
>
>
> From:
> Oliver Boyd <olboyd at usgs.gov>
> To:
> "ceus-earthquake-hazards at geohazards.usgs.gov"
> <ceus-earthquake-hazards at geohazards.usgs.gov>
> Date:
> 04/27/2011 10:09 AM
> Subject:
> [CEUS-earthquake-hazards] Article on Central U.S. Earthquake hazard     by
> expert panel
> Sent by:
> ceus-earthquake-hazards-bounces at geohazards.usgs.gov
>
>
>
> Dear CEUS earthquake hazards email list subscribers,
> Below is a link to a short article about the findings of a National
> Earthquake Prediction Evaluation Council expert panel regarding central
> United States earthquake hazard.
>
> http://news.sciencemag.org/sciencenow/2011/04/expert-panel-central-us-faces.html
>
>
> Regards,
> Oliver
>
> --
>
> Oliver Boyd, Ph.D.
> Research Geophysicist
> U.S. Geological Survey
> 3876 Central Ave
> Memphis, TN
> Phone: (901) 678-3463
> FAX: (901) 678-4897_______________________________________________
> CEUS-Earthquake-Hazards mailing list
> CEUS-Earthquake-Hazards at geohazards.usgs.gov
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