An earthquake measuring five on the Richter Scale struck Masafi last year. Though there was no loss of life, concerns arose about whether the UAE is vulnerable to earthquakes. No study has yet proven this, but the authorities are now making every effort to ensure lives and property are secure.
Abu Dhabi, Dubai and Sharjah sit on top of a fault line, which has been mapped transecting the Western coastline of the UAE.
Major faults have since been mapped and they penetrate the tectonic plates between the Arabian Peninsula and Asia. Scientists are not sure if this fault is active or not, but point to the earthquake which hit Masafi last year with a magnitude of five on the Richter Scale. Several tremors have since been recorded near Masafi.
If the epicentre of an earthquake of a magnitude of five or more on the Richter Scale is near a major city, it could be catastrophic. There is also another fault line which cuts across Dibba.Dr Azm S. Al Homoud, professor of Civil Engineering at the American University of Sharjah, told Gulf News that priority should be given to assess this seismic hazard.
There is a need to evaluate ground accelerations and design and construct structures accordingly. Dr Al Homoud is the co-author of a research conducted in collaboration with Max Wyss, professor of Seismology at WAPMER, Geneva, Switzerland.
Dr Al Homoud said there are reasons to take the threat of earthquakes in the UAE seriously. n An authoritative group of international experts has determined that the hazard in the UAE is about the same as that in parts of California, the U.S., Turkey and Iran.
* A major fault of unknown seismic activity level runs along the west coast, right through the major cities of the emirates.
* A magnitude five earthquake occurred in Masafi area at 23 km from Fujairah on March 11, 2002. If such an earthquake were to occur at the same distance from Abu Dhabi, Dubai, Al Ain or Sharjah, it would be a disaster. There would be significant damage to buildings.
This would not have been an issue some 40 years ago as there were very few buildings and the population was small.
It is clear that with rapid urbanisation and the real possibility of earthquakes near cities, the seismic risk in the UAE is increasing rapidly, and should not be ignored, he said.
According to Dr Al Homoud, the UAE's proximity to the Zagros earthquake belt in southern Iran has made the international working group that assembled the world-map for seismic hazards (GSHAP), to expect high ground accelerations in the UAE.
Ground acceleration
The potential of strong ground accelerations is estimated to equal those in most parts of Iran (a country in which many tens of thousands of lives have been lost due to earthquakes), and in California, another place which sits on a major fault line.
He asserts if leading specialists expect high accelerations here, the UAE should have local experts who can review this opinion, understand this hazard and prepare the population for the possibility of a strong earthquake and reduce the risk to the population.
Dr Al Homoud said another fault line passes through the centre of the Arabian Peninsula, and out to sea at Dibba. There exist other faults on the Arabian shield, which are not active.Why should one suspect that the fault line can set off earthquakes in the UAE? The Masafi incident is one factor, and secondly, because it is likely that ground stress is being built up in the prong formed by the UAE territories and into the southern coast of Iran.
Dr Al Homoud said: "Although we do not know whether or not the faults are active, they must be considered prime candidates for future earthquakes."
He suggests that an earthquake-monitoring network should be put in place. In the UAE, major cities and large buildings are a relatively new development, and there are no records of the effects of earthquakes in this area.
Soil conditions
In Dubai and Sharjah ground acceleration is a bigger threat due to adverse soil conditions. The 15 to 20 metres of medium dense to dense sand, sitting on firm sandstone, may play an important role in future earthquakes in the UAE.
This is precisely the type of soil condition that can further amplify ground acceleration. The best-known example of this phenomenon is Mexico City, in which numerous buildings collapsed due to an earthquake. The epicentre of that earthquake was 300 km away.
Moreover, the 15 to 20 metres loose to medium dense sand layers in the recent land reclamation projects may experience serious strength reduction from the ground shakings during earthquakes.
In order to ensure world class scale and type of earth-fill and land reclamation, Dr Al Homoud recommends that a cost effective proposal be implemented to study the hazard, taking into account the scale and size of buildings and infrastructure development.
He also recommends that studies be done to identify weak spots, suggest remedies to strengthen groundwork, design structures to withstand accelerations.
Earthquake Observatory at the American University of Sharjah. The first network for earthquake monitoring was installed in the UAE by the American University of Sharjah (AUS).
The project is named "AUS Earthquake Observatory". Three stations, each with an accelerometer, a recorder and GPS have already been installed at the AUS School of Engineering Building, Masafi Mountain and the Fujairah Municipality Building near the Ruler's Palace.
Monitoring
The first station has been operational since winter 2001 and the second and third stations have been operational and recorded data being communicated to the AUS Observatory Data Collection System since last Autumn.
A state-of-the-art seismograph was installed at AUS School of Engineering station in the summer of 2002. The monitoring project continues to expand as two more pieces of state of the art recording equipment, a seismograph and a strong motion sensor-recording system, will be installed in the following months in Abu Dhabi and Ras Al Khaimah.
Gulf News
