It is quite a bit more than half in Canada. A lot of others in ME and NH most all under 3. Only one over 3 since 2007 that I saw in southern NE was 420km E of Boston. The last one over 4.0 I could find was 1951 in RI. Being that this is mid-plate, they are more difficult to predict where. They can happen, but rarely (2011 in VA, 1884 in NYC, 1886 Charleston, etc.) Do you brace everything that resides on top of a tectonic plate? This is a game of probability, to a certain extent.
Todd G Williams, PE Fire Protection Design/Consulting Stonington, CT www.fpdc.com 860-535-2080 (ofc) > On Feb 21, 2014, at 5:15 PM, "Steve Leyton" <[email protected]> > wrote: > > Let's say half of them. And let's say that at least two were over 4.0 > magnitude. Where there's a 4.0 there's a 5 lurking and a 5.3 waiting to > shock the living daylights out of everyone. Seattle is definitely more > subject to seismic activity because it sits on the ring of fire, but > they hadn't had a bad quake in forever and the oldest inner-city > infrastructure was mostly un-reinforced. In 2001 they had a 6.1 that > lasted for something like 45-50 seconds and the damage was profound. > My point is that you're gonna have one here and there and all it takes > is a 3.5 in an old unreinforced building to blow everything up. I'm not > advocating we brace everything everywhere or retrofit where it hasn't > been mandated already, I'm just saying that generalizing isn't an > accurate MO. > > But here's an idea for those allergic to bracing: if you're in one of > these areas that's active, but where magnitudes are generally sub-3.0, > why not observe flexibility and restrain the branches? > > SML > > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of > Todd - Work > Sent: Friday, February 21, 2014 2:05 PM > To: [email protected] > Subject: Re: seismic bracing calcs > > Steve, > > I have seen that list. If you look closely, most of those readings are > from the eastern provinces of Canada. There are some in CT, but most are > in the 1.0 to 2.0 range (see Moodus Noises). There have been some dish > rattlers in the past, but not too many. The 1755 quake was estimated to > be in the 6.0 range. The majority of the more significant ones have been > centered in NH. > > FYI, one of the quakes noted on 11/29/13 was located within 1000 ft of a > church I did several years back. No damage. > > As far as the last paragraph, I will leave that alone. As a Pats fan > (and also have done a fair amount of work for Bob Kraft's companies), I > hope they have learned to get a good receiver and finally boost the > defense. > > Todd G Williams, PE > Fire Protection Design/Consulting > Stonington, CT > www.fpdc.com > 860-535-2080 (ofc) > >>> On Feb 21, 2014, at 4:33 PM, "Steve Leyton" >> <[email protected]> wrote: >> >> That's what you think. Go here: >> http://aki.bc.edu/cgi-bin/NESN/recent_events.pl >> >> Most recent temblors in New England were last week. Not big ones, but >> you have them all the time. This feeds into what I said about > changing >> times: those maps in the annexes of older NFPA 13 editions are > obsolete. >> Throw them away. >> >> There was also a pretty severe jolt on Jan 18 that was thought to be a > >> seismic event but turned out to be about 1.3 million people all >> sitting down at the same time when the clock ran out on the Pats in >> the AFC Championship game. >> >> Steve >> >> >> >> >> -----Original Message----- >> From: [email protected] >> [mailto:[email protected]] On Behalf Of >> Todd - Work >> Sent: Friday, February 21, 2014 1:21 PM >> To: [email protected] >> Subject: Re: seismic bracing calcs >> >> I think you also need to take into account regional differences. Some >> areas, like Leytonland, have a lot of earthquakes and potential for >> serious ones in the future. They need to be on top of that. The last >> major earthquake in New England was in 1755 off the coast of MA. >> Earthquake potential is not taken as seriously out here. You go to >> places like TX and it is virtually non-existant. There isn't the >> consistent demand on a national level. >> >> The only time in the last 10 years I have had a direct involvement >> with a structural engineer in when one guy used all his mechanical >> dead loads to support the solar panels and forgot about the 3 - 8" >> mains directly underneath going to the ESFR systems (which somehow was > >> my fault). The mechanical engineer looks to see if we meet their spec, > >> the architect wants to make sure it looks pretty, the insurance >> company reviews it for > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler > .org > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
