7.0 hits Haiti? 2

[msquared48]

What's goin' on?

Somehow, I never thought of this region as prone to earthquakes of this magnitude. Very strange to me.

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

 

[dgillette]

The island of Hispaniola (Haiti and Dominican Republic) is actually very active, being located at a plate boundary. They get a really big one once or twice a century, the last one having hit the DR in the 1940s.

See Table 3 on page 341 of:

http://www.jstor.org/stable/4312732?seq=2

and

http://books.google.com/books?hl=en...epage&q=seismicity dominican republic&f=false

While in the DR for a seismic conference some years ago, the organizers drove us out to see one of the major faults, which had caused 100+ feet of displacement of a creek bank over some relatively short period, creating a big "Z." Truly eye-opening. Then, they showed us what I think they said was the remains of the first church built in the New World, which was destroyed by an earthquake within a few years. (My Spanish is not great, so I won't swear that's what I was told.)

 

[jt12]

The 1997 UBC had some seismic risk factors for various non-U.S. regions. I don't have one in front of me to check on haiti. Parts of Venezuela were risk category 4, but it seemed like it reduced as you went into the carribean.

 

[Qshake]

The location of a small yet apparently unsettled Carribean plate. And where there are plate boundaries....

Will be a terrible outcome. Lot of the local housing is nothing but concrete with little reinforcing and i'm certain that what is in place is very likely not placed properly. Moreover, the heavy roofs will play havoc with the thin brittle walls in the out-of-plane direction.

Unreinforced masonry/concrete is very popular in these sorts of places similar as it is in Mexico outlying the main city. Or even in South America. No steel or good solid wood construction.

Regards,
Qshake

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

 

[msquared48]

From the latest article:

Dale Grant, a U.S. Geological Survey geophysicist in Golden, Colorado, told Reuters there had been no quakes this large in Haiti for more than 200 years.

"There were two major quakes there in 1751 and 1770 but, since then, there has not been a quake of this magnitude," Grant said.


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

 

[hokie66]

According to this, there was an 8.0 near there in 1946, and a dozen major earthquakes in the region in the last 500 years.

http://www.cnn.com/2010/TECH/science/01/12/caribbean.earthquakes/index.html

 

[concretemasonry]

It would be interesting to look at the damage to the hospital, since hospitals are usually considered critical and designed to a higher standard than normal.

The dome of the government center is on the ground, so apparently, the shake was not is the codes or the standards used.

Dick

 

[ishvaaag]

In my view some of the earthquakes we are seeing these days are adaptation to the loading by ice and snow in the northern continents. These float on the mantle.

 

[JLNJ]

7.0 located just 10 miles deep and something like 10 miles from Port Au Prince.

If you go to the USGS website you can click on the seismic hazard for the area of this quake and see that it is in a low to moderate zone. Supposedly, the seismicity jumps up as you go east from there but whoever published that seismic hazard map may be re-thinking that area. Such is the danger of using recorded history to guess at millions of years of geology.

 

[paddingtongreen]

I heard that the hospital collapsed, many cries for help.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[msucog]

i've been following world seismicity for several years now and it certainly seems as if "something" has been building over the past year or so and especially in the past say 3 to 4 months (purely observations on my part...nothing statistical). the only place that hasn't seen a substantial earthquake lately seems to be the ceus which sort of concerns me. the activity almost seems to be cascading outward from the sumatra area north and east across the pacific toward the ceus (again, purely my unscientific observations). the world almost seems to be busting at the seems when you look at the past several months of earthquakes. throw in recent volcanic activity and it makes for interesting scenarios of "what ifs".

Ryan Coggins, P.E., S.I.

http://www.linkedin.com/in/ryancoggins

 

[dgillette]

Depends on how you define "near." The 1946 EQ was nearer Santiago, DR, maybe 150 miles northeast of this one.

 

[msquared48]

So far, in the pictures I've seen, the only rebar in the masonry I noticed amounted to no more than K-web or, MAYBE, #3 bars. A pittance any way you look at it.

To be quite frank, I noticed the same construction in the Cascun area of Mexico 15 years ago. Seemed to be the norm for small masonry buildings of 3 to 4 stories.

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

 

[msucog]

Yes it appeared to be lacking a bit of reinforcement. The news was reporting earlier that Haiti has more stringent guidelines related to the building code.

I just saw a report that they are putting the death toll in at least the 1000's and possibly 100k.

Ryan Coggins, P.E., S.I.

http://www.linkedin.com/in/ryancoggins

 

[concretemasonry]

Construction and design (if it exists)in Haiti is 10 levels lower than China, which everyone ridicules for cheap tools made for U.S. importers. The Chinese buy more Buicks than the U.S., but Buicks are #3 on the import list.

It is just depending on the market requirements and politics.

Real codes and enforcement in Haiti is non-existant. Other islands do have much higher requirements and standards, but good masonry construction is the norm.

I look forward to getting there to look at the failures and causes.

Dick

 

[msquared48]

What gets me, is that with the economic depravity of the Hatian economy, how the H are they going to rebuild?

Moreover, now that the "big one" has technically occurred for them, will this be enough of a political impetus to change the codes and adhere to them? Somehow, with the embedded political corruption there, I don't think so...

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

 

[Qshake]

No, I don't think things will change for them in terms of code and certainly not in practice.

What I forgot to note in my earlier post is that they don't build with wood and steel or even rebar as it is hard to get and therefore expensive. Hence in most of the Central and South American areas as well as Carribean the material of choice is masonry or adobe.

Regards,
Qshake

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

 

[msquared48]

OMG... I actually saw three #5 bars!

Problem is, whether it was a beam or column, there was absolutely no shear or confinement steel. None whatsoever.

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

 

[msquared48]

I also saw a lot of CIP concrete beams and column "skeletons" with masonry infill that had obviously failed. No tie from the beams or columns to the masonry "shear walls", and I say shear walls with tongue in cheek.

It is absolutely ludicrous and criminal to me that the hospitals, presidential palace and communication facilities have collapsed.

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

 

[unclesyd]

Does anyone know how many degreed engineers of the mechanical bent are in Haiti?
I heard a number (21) some time ago that seems awful low.