Seek information on land suitablity before.....(pg32)

The Head of the Seismic Monitoring Unit of the Geological Survey Department, Mr Sylvanus Ahulu, has advised estate developers and prospective home owners to seek information on the suitability and safety of plots of lands in the event of earthquakes before developing them.
He told the Daily Graphic that “identifying the geological formation under the ground will help architects and structural engineers to design and build earthquake-resistant structures”.
“Tracking earthquake active zones or fault zones will also facilitate siting important lifeline structures, such as hospitals, schools, communication gadgets and major security installations, away from zones of high seismic risk,” Mr Ahulu said.
Last Sunday night’s earthquake scare and the recent earthquake in Haiti which resulted in a mass collapse of buildings and the death of thousands of people have raised concerns over Ghana’s ability to mitigate the consequences of a possible earthquake.
Citing the Cedi House in Accra as an example, he explained that when work started, the contractors contacted the GSD to conduct a ‘foundation investigation’ at the site and they found that the present car park on which the building should have been constructed posed an earth threat so the design and the site had to be shifted a bit.
He indicated that the National Theatre, which was built without any such information or contribution from the GSD, developed some cracks when the March 6, 1997 earth tremor which measured 4.5 on the ritcher scale hit the country.
Presently, no law exists in Ghana that makes it obligatory to seek geological survey information before putting up structures, making the housing sector vulnerable should an earthquake of high magnitude strike the country.
Ghana's experience with earthquakes started in 1615. Another earthquake which occurred in East Nzema in 1636 caused a lot of devastation, with Axim being the worst victim. Several buildings were knocked down, while a gold mine at north east Axim was reported to have collapsed, taking with it many miners.
Subsequent ones were in 1862 and 1906, with the earthquake of 1939 being the worst in recent history, measuring 6.5 on the ritcher scale. It killed 17 people, injured 133 others and had the roof of the seat of government, the Christianborg Castle, ripped off.
The identification of earthquake-prone areas carried out in Ghana after the 1939 earthquake and other studies showed that the southern part of the country remained vulnerable to major earthquake threats in the very near future.
Historical records and repeated tremors experienced in Accra and its environs heightened the fear of occurrence of a damaging earthquake in the country, with Weija, Nyanyanu, McCathy Hill, Ho and Akosombo declared Ghana’s earthquake epicentres.
Mr Ahulu said in spite of the declaration, new and magnificent buildings continued to spring up in those areas, with no recourse to the dangers such structures posed to their inhabitants, especially when the developers did not conduct geological studies on “how secure such places could be”.
He said earthquake-prone areas in the “northern part of the country have not been identified yet” because of logistical constraints hampering the work of the GSD.
He said even though earth movements occurred randomly in the country, they were only instrumentally felt or measured, adding that “it is through this that we are able to develop Seismic Hazard maps for the country which give a fair idea of areas that can experience earthquakes or tremors”.
He said a networked Ghana monitored by a seismograph, the device used to measure and record earth tremors, would ensure that the GSD detected all active zones and ultimately developed a seismic hazard map for the country.
Meanwhile, the country’s only seismograph has broken down, making the detection of active earthquake zones a difficult task.
The equipment, which was acquired in 1974 and retooled in 1992, ceased working two years ago, making the country dependent on other countries to report earth movements in Ghana


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