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Accomodating Recent Increase in Earthquakes

Accomodating Recent Increase in Earthquakes

Accomodating Recent Increase in Earthquakes

(OP)
How are you accounting for the global increase in seismic activity?

Earthquakes have increased. Has anyone modified their design procedures to account for the increased probability of seismic events?

I am being extra cautious in considering building design, and especially connections. I've been reading and improving my design process.

I've been looking at buildings that failed.

What are others doing?  

RE: Accomodating Recent Increase in Earthquakes

Constantly updating my disaster pack.

Mike McCann
MMC Engineering
Motto:  KISS
Motivation:  Don't ask

RE: Accomodating Recent Increase in Earthquakes

(OP)
Mike,

By disaster pack, do you mean copies of ATC-20 and other evaluation materials?

What is your disaster pack?  

RE: Accomodating Recent Increase in Earthquakes

I am ATC-20 trained and prepared, but, no, I mean my personal and family disaster plans and survival supplies.  

Living where I do, it's just a matter of time before we will be seeing what a lot of other locations in the world already have.   

Mike McCann
MMC Engineering
Motto:  KISS
Motivation:  Don't ask

RE: Accomodating Recent Increase in Earthquakes

In the northeast, DoT's have been requiring ince the mid-90s that we design for seismic. The NYC Building Code adopted seismic requirements around 1990.  

I don't necessarily agree with an "increased probability of seismic events"; does anyone really know why EQs happen? I'm being philosophical not technical.

RE: Accomodating Recent Increase in Earthquakes

Please provide your source of information on the "global increase in seismic activity"?
 

RE: Accomodating Recent Increase in Earthquakes

(OP)
Well, here is an article from USGS saying there is NO increase:

http://www.washingtonpost.com/wp-dyn/content/discussion/2010/03/08/DI2010030802570.html

The measuring of earthquakes has changed. Prior to the 70's, the Richter scale was used. Today, the "moment magnitude" scale is used. (Excuse the wikipedia link... its a good summary)

http://en.wikipedia.org/wiki/Moment_magnitude_scale

Here is Time's list of the top 10 quakes of all times. Printed in 2010, it omits the Honshu quake. Add that in, and 4 of the top 10 are in the last decade:
http://www.time.com/time/specials/packages/completelist/0,29569,1953425,00.html

Ah. Here is the winner: USGS compiled quake totals worldwide. The increase is obvious:

http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php

The table at the above link is best. All the measurements are on the same Mw scale.  

RE: Accomodating Recent Increase in Earthquakes

there is no significant increase in earthquakes (only in deaths) shown in the USGS table. In fact according to this table, it appears there may be a worldwide decreasing trend. 2010 appears to be a bad year for the US, however it appears that 2011 is on track to be at or below average. I am not convinced that 10 years of data is sufficient for valid statistical analysis regardless of what Time Magazine says.


 

RE: Accomodating Recent Increase in Earthquakes

Somehow, with all the recent activity on the Pacific rim of fire, I highly doubt that there is has not been an increase.  I have never seen such activity, particularly with the larger quakes.

Just don't buy the no increase scenario...

Mike McCann
MMC Engineering
Motto:  KISS
Motivation:  Don't ask

RE: Accomodating Recent Increase in Earthquakes

I am not a conspiracy theorist, but I do keep my eyes open.  

My guts, and I do trust them, tell me the number and magnitudes are increasing, and I'll just leave it at that.

Mike McCann
MMC Engineering
Motto:  KISS
Motivation:  Don't ask

RE: Accomodating Recent Increase in Earthquakes

As well as having the ability to detect more earthquakes, we receive much more information about them from the media.  I put it in the same category as climate change...runs in cycles.

RE: Accomodating Recent Increase in Earthquakes

I guess it won't be long before it will be claimed that Man is somehow causing said increase, if there is one, and that with adequate/necessary funding (of course ultimately with increased rates, taxes, fees, or regulations yaddah yaddah yaddah) some study or theoretical mitigations/remediations to react to all this can be done by our omniscient powers-at-be.

A read and look at the pictures etc. in the thread http://cr4.globalspec.com/blogentry/16290/Japan-Earthquake-Engineering-and-the-Illusion-of-Total-Safety may however be worthwhile(if you have not seen). While it is true of course that smart and persuasive Engineers and politicians are capable of great things, I fear sometimes however that we may sometimes overestimate our own knowledge, capabilities/Power and influence.  I particularly like the quote of xanasax in this referenced thread,

"If man made it, then God can tear it down"  

[Everyone have a good weekend, and msquared48, you may want to pack a slide rule like I have in my little disaster kit, as you may find they run a little better than electronic calculators and computers when there is no power!]
 

RE: Accomodating Recent Increase in Earthquakes

I agree with Hokie66, this is a natural phenonmenom that will run in cycles.   

Regards,
Qshake
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Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
 

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