[CEUS-earthquake-hazards] reply to Joe Tomasello; buildings codes and earthquake hazard

[Wang, Zhenming]

Art,

I think the bulletin board serves the purposes well. I learn a lots from the discussions.

First of all, all I have discussed through the listserver are not personal, but the Kentucky Geological Survey (KGS)'s positions and understandings on the USGS national seismic hazard maps. These positions and understandings have been discussed with you and your colleagues in the past several years through professional meetings and publications, workshops, private meetings, and official letters. As discussed, making a seismic hazard mitigation policy is a complicated process, but seismic hazard assessment is the basis.  KGS is focusing on the basic earthquake science and seismic hazard assessment.

What we found through the long and difficult discussions are "that the national seismic hazard maps are not consistent with modern earthquake science, particularly their methodology (probabilistic seismic hazard analysis - PSHA)."  These are the reasons why the maps are so difficult to understand and use. The mitigation policies based on the national seismic hazard maps may not be scientifically sound.

As discussed, earthquake science is complex, particularly in the New Madrid seismic zone. However, scientists (seismologists and geologists) should communicate the earthquake science in a simple and understandable way. Often times, the earthquake science is presented too complicated to be understood.

Thanks.

Zhenming



________________________________
From: Arthur D Frankel [mailto:afrankel at usgs.gov]
Sent: Friday, February 15, 2008 11:19 AM
To: Wang, Zhenming
Cc: ceus-earthquake-hazards at geohazards.usgs.gov; James Cobb; Keifer, John D
Subject: RE: [CEUS-earthquake-hazards] reply to Joe Tomasello; buildings codes and earthquake hazard


Zhenming,

  I am sure many people on the bulletin board are getting tired of these exchanges.

 I presented similar comparisons at the Applied Technology Council workshop in Memphis in March 2005.  As I recall, you and Joe Tomasello were in attendance.   So I think you have seen these comparisons.

Of course, I don't see any contradiction in what I've said.   I think it is reasonable to compare code values with the expected ground motions from the next 1811-12 type earthquake and with ground motions estimated for the 1811-12 earthquakes using intensity observations.

  I think further discussion between us on these issues should be made off of the bulletin board.

-Art


Art Frankel
U.S. Geological Survey
MS 966, Box 25046
DFC
Denver, CO 80225
phone: 303-273-8556
fax: 303-273-8600
email: afrankel at usgs.gov

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