Facts About the 1999, Turkish Earthquake in Izmit
The earths crust is made up of rocky plates some 36 miles thick. These massive plates are known as 'tectonic' plates or shelves. The earth's continents slide around on these plates as course, but every now and again two of these plates meet and one will push against the other, causing massive drag of one against the other.
Scientists believe there are two reasons for this; one is heat or convection in the mantle layer just below the earths crust, or a gravitational pull squeezing plates together.
This particular earthquake was easy to define; it was caused by a strike-slip movement along a region known as the Anatolian Fault. This fault in the earths crust stretches from the centre of Iran and into the north west of Turkey. This fault line meets up with two others along the way, the Eurasian strike slip, and the Arabian plate.
This particular quake affected an area of over 250 kilometers. It was the eleventh such quake along this fault line since 1939. The first ever recorded in the area was in 1754 with the loss of 2000 lives.
The quake struck at two minutes past three on the morning of 17th of August 1999.The quake measured 7.4 on the Richter scale, and had a duration of 45 seconds. The movement that this produced was of a magnitude of 40% acceleration from the gravity at its epicenter. This movement caused the ground above it to shift 10 feet from its normal lateral position. The cataclysmic energy that this movement caused had the effect of a hundred mega-tons of T.N.T.
As a result of this damage, 17,000 people died, 23,000 were injured and 1.5 million were made homeless.
23,000 buildings were destroyed and 120,000 left needing structural repair.
Building loss amounted to over 6 billion dollars and restructure of the area was put at over 20 billion dollars.
Location of Izmit in northern Turkey
The outside limit of survival for someone trapped in a collapsed building is a week. That is to say someone fortunate enough not to have suffered injury. The younger the victim the better the rate of survival. Although babies and small children suffer the affects of dehydration much sooner than an adult, they tend not to suffer the logical senses of fear, anxiety and panic that adults do. Reports of babies being pulled from the rubble of buildings as much as ten days later, is not unusual. Most adults begin to succumb from the affects of dehydration, fear and organ degeneration from as early as 72 hours.
The reason so many perished in this quake were twofold. First was its ungainly timing, coming at a time when most inhabitants were asleep in their beds.
The second was man made. The high rise apartments that housed the residents of the largest industrial city in Turkey were built in the most appalling manner.
Izmit is home to Turkey's vast petrochemical, automotive and construction industries, but it would seem that their employees were forced to live in the most sub-standard of dwellings.
Findings from the subsequent inquiry into the quake found that contractors had built these apartment blocks using a more ' sand to cement ' ratio in the concrete mix and low grade re-enforcement girders. There is no code of practice in Turkey for building standards.
The type of damage a building sustains from an earthquake depends on three things.
1) How well the building was constructed.
2) What type of land the building was constructed on.
3) Duration and velocity of ground movement.
In areas where earthquakes are a problem, builders have strict guidelines on construction to ensure minimal casualties to occupants. We have already ascertained that these guidelines do not exist in Turkey as do guidelines for general building works. Thus, a building can be constructed any where regardless of any dangers from resultant underlying ground problems.
As teams of consultant research analysts toured the area days after the quake, they were amazed to witness every type of building with every defect known to the industry. This was ascertained by checking the type of damage the buildings had sustained.
Pancake layering which causes a building's stories to lie pancaked on top of one another, signifying that the building had been constructed of too soft concrete mix; too much sand not enough cement. This is done as a cost cutting exercise for the builder.
Total subsidence, where a building collapses in its entirety, this happens due to there being no roof infill and ground floor sections being left as open areas for the use of shops and / or offices at ground level. Again this is done as a cost cutting exercise as great savings are made to the developer if costly materials for these areas can be ignored.
Sunken buildings are where the first two or three stories have completely disappeared below ground. This is due to underlying soil failure owing to the fact that buildings were constructed on water saturated ground or landfills. Again another money saving venture by developers as this type of sub standard land is obviously cheaper to buy than its more stable counterpart.
Sea water inundation brought on by buildings being situated too near to the sea front or in high tidal areas. Again these areas are a cheap option for any builder or developer owing to the danger it presents to water damaging foundations.
Earthquake damage, notice how the two buildings are holding each other up next to a building that has completely sunk into the ground.
The 1.5 million people displaced by the quake were put up in 'tent cities' erected in local parks around the town by the emergency services. The tent cities were paid for by oversees volunteer groups, who also ran and maintained them.
Teams of doctors, nurses, psychologists and translators were drafted into the area from all over the world to help the stricken survivors.
Teams of firefighters, dog handlers, trauma specialists, civil engineers, and esoteric specialists, were assigned to help the trapped victims and bury the dead.
Along with these specialist groups from all over the world, came their specialist equipment in the form of cutting gear, fibre optic cameras, listening devices and heat seeking imagery.
This building has suffered from total subsidence, what you can see are the top two stories of a much taller building.
The main problem of immediate concern from any disaster is the prevention of air and water borne diseases.
Rotting corpse, ruptured water and sewerage pipes, lack of washing and toilet facilities and rubbish and waste disposal facilities all play their part in speeding up the process of the multiplication of bacteria. These elements and Turkey's normal August temperatures of over 30 C degrees (86 F), all meant that the emergency services had to work with great haste.
A quake of this magnitude can result in after shocks being felt for weeks, months even years later. These aftershocks can come at any velocity and be felt in areas many miles away from the original quake zone.
This building looks like it has slipped on a banana skin, this is due to the waterlogged ground it has been built on.
Although this quake occurred on the worlds longest strike slip fault, in an area used to dealing with this type of disaster, the worst single feature of it was its duration. Forty five seconds of continual seismic activity at a rate of 40% acceleration, coupled with its timing and Izmit's shoddily built dwellings, has rendered this earthquake Turkey's worst natural disaster.
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© D.B.Bellamy. April 2010.
Images courtesy of wikimedia commons.