seismic hazard probability to Richter scale

[cmrdata]

When we design/evaluate a building structure to resist specific seismic hazards, we have been using the concept of "probability of exceedance" and "mean return period". For example, when design to BSE-1E and BSE-2E per ASCE 41-17, we are talking about a 20%/50 year (225 year return period) and a 5%/50 year (975 year return period) event, respectively.
Very often Building Owner would ask us to put it in laymen's terms, such as Richter Magnitude, so they can understand the hazard levels we are referring to.
I understand this might involve the distance between the potential fault nearby to the building site, historic seismic occurrence data base, geologic/geotectonic/geomorphic data base, etc., and a direct correlation might be more complicated than I assume there. However, is there resources I can go to to get some quick preliminary information to "convert" hazard probabilities to Richter Magnitude at specific building site?
Thanks,

 

[JAE]

There's several threads here that have talked about this. Do a search for "Richter".
Here's a few:
thread487-371415
thread487-146590
thread176-299303
thread507-28430
thread507-269906
thread507-430032


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[IRstuff]

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[TLHS]

This is a hard question, even if you explain the correlation of PGA and other measures. We aren't designing for seismic forces the same way we're designing for other forces. We are designing to prevent loss of life and catastrophic collapse under a design level event. Depending on the type of structure, you could get serviceability level damage starting at widely varying values and still be a compliant structure. Hell, you could have a building that has large amounts of ductility and is more effective from a life safety standpoint that tears out all it's water and electrical service connections at a way lower level than a brittle structure that has a much lower collapse ground acceleration.

You're designing buildings to, on a balance of probabilities, not kill someone at the design level event. With probabilistic scatter on materials and variance in events, it's completely possible to have properly designed buildings collapse in design level events if there's low redundancy.

If you tell someone that you're designing for a fifty year return period snow event and that this is 3 feet of snow, they're going to understand that everything will be fine up until that point and there's some play after that. This isn't how earthquake design works.

Any discussion with a layman about earthquake design goals needs to start with this.

 

[cmrdata]

Thank you JAE, for the helpful links you provided.