Dust flux, Vostok ice core

Dust flux, Vostok ice core
Two dimensional phase space reconstruction of dust flux from the Vostok core over the period 186-4 ka using the time derivative method. Dust flux on the x-axis, rate of change is on the y-axis. From Gipp (2001).

Wednesday, November 7, 2012

Melcom building collapses in Achimota (Accra)

A six-story building collapsed in Accra today. It is the first time such a thing has ever happened.

The principal tenant of the building, occupying the lower three floors, was Melcom, a department/grocery
store (think of something like Walmart).

Luckily the building collapsed before opening, otherwise there would have been hundreds of people trapped
inside. As it is, about 55 employees were inside the building when it collapsed. One report says that 48 people have been removed from the ruins, with only five deaths. Furthermore, there are still people inside calling on cellphones asking for help and water, so it seems that the number of deaths will be much smaller than first assumed.

I've been watching images of it all day on one of the local channels. The building completely pancaked except for part of the ground level (or perhaps it was the basement). The concrete slabs of all of the remaining floors have all piled on top of one another, with the external support columns failing outward. It is as bad as any collapse I have seen after an earthquake. I would put it up there with Armenia (1988). It is still too early to be sure, but I would suspect faulty building materials (also the case in the Armenian earthquake).

The building was considered to be a fine example of a high-tech building. It was built in only two months, using new (to Ghana) construction techniques, but the reporting has been unclear as to the identity of the builder.

We have built a few small buildings ourselves in the course of our project here in Ghana. In general, the quality of available concrete block is very poor, with many block-makers using inadequate amounts of cement to bind together material that includes sticks, grass, leaves, and charcoal.

Block factory production in Weija (note sticks).

Wall in Weija made with low-quality block.

During today's coverage, the reporters revealed that Accra is in an earthquake zone, and cast doubt as to whether many of the modern buildings recently constructed have been built to a standard suitable for one. Furthermore, the same company that built the collapsed building has also built buildings in downtown Accra, which is making some people nervous.

Update Nov. 8 6:40 p.m. local

They are now saying 69 people have been rescued alive from the collapsed building, along with eight deceased.

An Israeli rescue team has arrived with sniffer dogs and various listening/looking devices to look for more survivors.

The owner of the building has been asked to turn himself in (but has not taken up the offer--no surprise there).

I had avoided comments on the age of the building in the original post, as there was too much conflicting information, with some sources saying the building had been recently completed in only two months, while the tenant claimed to have rented the building for ten years. It seems that the tenant has rented the building for ten years, but recently had three floors added to it--this new construction was done in only two months.

Such a project would raise concerns in my mind. Given the nature of the ground conditions (laterite/sand)--was the original low-rise situated on a slab which was adequate for a two-story building but not a five-story one?

Update Nov. 9 evening

More struggles with power and internet. Joy News reports 75 rescued and 10 fatalities, but still numerous survivors known to be in the wreckage, some of whom have been communicating by cell phone.

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