CALAMITY , FEAR AND PAINFUL MEMORYS

                                                                                                                                                                                                                                                                                                                                                            CALAMITY , FEAR AND PAINFUL MEMORYS 

   

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What IS A FAULT?

A fault is a discontinuous displacement of rocks along a surface. A fault therefore separates two adjacent rock masses into blocks with a thin zone of crushed rock called gouge in between. A fault must have observable shear displacement between the adjacent geological units, otherwise we call the fracture a joint. Faults can be any length, from centimeters like in laboratory deformed rock samples to thousands of kilometers like the San Andreas or Anatolian fault zones. Fault surfaces can be at any angle to the surface of the earth, and the direction of motion along the fault can also be at any direction. A fault that breaks the surface of the Earth creates a line across the surface called the fault trace. The angle in a clockwise direction between the fault trace and a line on the surface pointing North is called the fault strike. The fault dip is the angle the fault makes with the surface of the Earth, the fault slip is the amount of displacement, and the rake is the clock-wise angle between the direction of slip along the fault and horizontal. The throw along the fault is the total vertical offset between the top and bottom of an offset geological unit such as a layer of limestone. Seismology inherited the terms hanging wall and footwall from mine engineering. Mine tunnels were often excavated along faults; when the fault surface was overhead the miners called it a hanging wall since they would hang lanterns from that wall; when the miners walked on the fault surface they called it a footwall.

What IS AN EARTHQUAKE?

            Earthquakes occur when stresses in the earth reach a level greater than the strength of the rock, causing the rocks on opposite sides of the fault to suddenly and violently slip past one another. Stresses acting perpendicular to the fault push the rocks on either side of the fault together. The strength of a fault is related to the size of these stresses and the coefficient of friction of the material forming the fault. At the same time, other stresses act parallel to the fault plane to move the rocks past each other. When enough stress accumulates to overcome the strength of the fault, an earthquake occurs as the rocks snap back toward equilibrium, and release the stored energy in the form of seismic waves, which shake the surrounding rocks. H. F. Ried first developed this hypothesis of how earthquakes occur, called the elastic rebound theory, following the (Great) 1906 San Fransisco earthquake.
            Whenever a noteworthy earthquake occurs newspapers, television broadcasts, and scientists quote many terms and quantities not included in the average person's vocabulary. For example, the rupture surface is the portion of the fault which slips when the earthquake occurs. The earthquake rupture begins at one point on the rupture surface called the focus or hypocenter specified with a latitude, a longitude, and a depth. The epicenter is the point on the earth's surface above the hypocenter, specified with only a latitude and longitude. The rupture progresses from the hypocenter along the rupture surface at a finite speed until, for some reason, it stops. The total time of shaking caused by an earthquake is related to the length of time needed for the rupture to progress along the entire rupture surface.

A rupture may stop because all of the accumulated stress is released, because it reaches a stronger section of the fault, or because it reaches the end of the fault. What physical conditions allow a rupture to begin, and what causes it to stop are important questions earthquake researchers are now attempting to answer.Generally, but not in all case earthquake rupture begins at some

point many kilometers deep within the lithosphere and progresses updip along the fault plane over the entire rupture surface.

            If the earthquake occurs underneath the sea and continues almost to the sea floor, then the earthquake may create a tsunami. Tsunamis are popularly and erroneously called 'tidal waves,' but have nothing to do with tides or weather.

What ARE THE DIFFERENT TYPES OF FAULTS?

            Scientists classify faults into strike-slip or dip-slip types according to the motion along the fault. Strike-slip faults are approximately vertically dipping with horizontal displacement along the strike of the fault. When looking across the fault, if objects on the opposite side move to your right the fault is a right-lateral strike-slip fault, and if objects on the opposite side move to your left the fault is a left-lateral strike-slip fault.

Dip-slip faults are inclined at some angle to the surface, and displacement is primarily normal to strike direction, along the dip of the fault. Geologists give more descriptive names to dip-slip faults depending on the direction of the displacement. For example, on a normal fault the foot wall moves up with respect to the hanging wall. Normal faulting occurs in response to lithospheric extension with the fault plane dipping away from the uplifted rocks. Reverse faulting occurs in response to lithospheric shortening, or compression with the fault plane dipping beneath the uplifted rocks. On a reverse fault the foot wall moves down with respect to the hanging wall. When a reverse fault has a small dip angle, geologists call them thrust faults. Blind thrust faults occur at some depth but do not extend to the surface, forcing the layers of rock above the fault to bend instead of break.

WHAT ARE THE DIFFERENT TYPES OF EARTHQUAKE?

 Seismologists classify earthquakes according to the motion on the fault and fault type as strike- slip and dip-slip earthquakes (see the previous question for the definitions). Earthquakes that are a combination of strike-slip and dip-slip movements, are called oblique-slip earthquakes. Earthquakes may also be classified in terms of the origin of the stresses that produce them; e. g., volcanic earthquakes are caused by stresses associated with a volcanic eruption.

HOW COMMONLY DO EARTHQUAKE OCCUR?

The answer depends on the size of the earthquake. Over the entire Earth, the number of earthquakes with magnitudes of 8 and greater is less than one each year. However, each year there are about 10 earthquakes of magnitude 7 or greater and 100 earthquakes of magnitude 6 or greater. No matter where they occur, these earthquakes are all powerful enough to be recorded by all or mostly all of the world's sensitive seismograph stations, such as UTIG's station HKT.

            Each year there are probably also about 1,000 earthquakes of magnitude 5 or more, 10,000 of magnitude 4 or more, etc. However, a seismograph station must be very close to the epicenter to recorded smaller earthquakes; thus, many small earthquakes occurring in remote areas of the Earth are never recorded, located, or catalogued.

CAN EARTHQUAKE OCCUR ANYWHERE?

            Wherever faults exist an earthquake can occur. That includes places that have never experienced an earthquake in recorded history and places listed as devoid of any reasonable risk on seismic hazard maps. However, earthquakes are much more likely to occur in some places than others; they are most likely along the boundaries between tectonic plates and at particular points of weakness within plates.

WHAT IS A SEISMOGRAM?

            Seismologists call a record of the ground motion at a particular point on the Earth's surface a seismogram. A seismometer measures the ground motion, usually by observing the behaviour of an appropriately oriented pendulum, or by observing the electromagnetic fields needed to keep a mass stationary. The seismograph is the whole package: a device for measuring ground motions and one for processing those motions so they can be recorded.
             The earliest seismic instruments were seismoscopes, devices designed with an unstable element which changed when an earthquake occurred. For example, one kind of seismogscope was just a bowl of mercury surrounded by little cups. An earthquake's shaking would slosh mercury into the cups; the amount spilled told something about the quake's intensity; which cups were filled told something about direction. The earliest seismographs resembling modern instruments were deployed in Europe and Japan in the last half of the nineteenth century. However, until about 1910 the physics of seismic waves was too poorly
 understood, seismographs were too crude, and their timing was too inaccurate to study earthquakes the way we do today. Thus, our record of earthquake activity worldwide only is complete back to about 1900, even for very large earthquakes.
             The first truly world wide network was the World Wide Standardized Seismograph Network, or WWSSN, deployed in the early 1960's, The WWSSN actually was meant to detect underground nuclear explosions, but in addition contributed greatly to our knowledge of the structure of the Earth and the physics of earthquakes. WWSSN instruments were relatively simple instruments compared to modern systems; the completely analog WWSSN systems were sensitive only to a narrow frequency band of seismic waves, and used photographic film to create permanent seismograms. Modern digital seismographs such as UTIG's station HKT, record ground motions over a very wide frequency band and have a great dynamic range, meaning they can record both small and great earthquakes.

WHAT IS EARTHQUAKE MAGNITUDE?

            Earthquakes vary broadly in size; from microscopic fractures to slip occurring on a fault hundreds of kilometers long. Earthquakes also vary in location and depth. Individuals would probably notice a small earthquake occurring a kilometer below the surface, but a larger earthquake occurring several hundred kilometers below your feet may not be noticed at all. Therefore scientists have developed procedures for measuring the size of an earthquake independent of location, depth, or damage to structures.
            Charles F. Richter introduced the concept of earthquake magnitude in the 1930's. Basically, his "scale" measured the maximum signal amplitude recorded on a standard seismograph, then corrected this for distance and instrument gain to obtain the magnitude. Richter developed his magnitude scale only for earthquakes occurring in California and measured on one specific type of seismometer, a Wood-Anderson torsion seismometer, designed to record the velocity of ground motion on photographic film. To find the magnitude, one measures the maximum amplitude A from the photographic record using a metric ruler.

What IS EARTHQUAKE INTENSITY?

 Scientists and engineers often describe the effects of ground shaking on humans and man made structures in terms of earthquake intensity. Earthquake intensity is judged on the Modified Mercalli scale and is, by definition, subjective, since it doesn't depend on instrumental measurements, but instead on the observer's assessment of damage or shaking. A level III intensity indicates rattling doors and windows, broken dishes, and cracked plaster. The highest intensity, XII, is reserved for total devastation, with shaking so severe that objects may be thrown vertically into the air. Intensity differs from earthquake magnitude in that the severity of shaking from any earthquake varies from place to place. A map of intensity values from a single earthquake will have isoseismal contour lines drawn on it to provide a representation of the broad variations in shaking over the region surrounding the earthquake epicenter. As distance from the epicenter increases intensity generally decreases.

WHAT FACTORS INFLUENCE INTENSITY?

            The most important factors influencing intensity are:

• Magnitude - Larger earthquakes occur over longer faults and have longer source durations. Earthquakes start at a single point (the hypocenter) and progress as a front over the rupture surface. The entire rupture surface creates the shaking you feel, and the shaking will continue as long as individual points along the surface continue moving. The duration of shaking is directly proportional to the amount of damage incurred by structures.
• Distance From The Fault - The effects of motion on a fault die off with distance, so that shaking decreases with distance from the fault.
• Soil Conditions - Unconsolidated sediment and soil can amplify the shaking due to an earthquake. Shaking felt over soft, loose soil is more intense than that on hard rock at the same distance and orientation with respect to the epicenter. The amplification of shaking increases with the thickness and looseness of the soil. In cases of very intense shaking, the soil may completely loose cohesion and become liquified.
• Construction - Buildings constructed from unreinforced masonry, adobe, or wattle never fair well during an earthquake. Buildings constructed on a wood or steel frame, such as most modern houses, survive ground shaking fairly well because the frame flexes in response to the shaking. However, moderate shaking can destroy frame buildings that are not well anchored to a foundation.

• Radiation Pattern - Earthquakes do not radiate energy equally in all directions. Thus, the amount of shaking a structure undergoes is also related to the orientation of the fault with respect to the building location. See the explanation of earthquake focal mechanisms above.
• Directivity - The direction the earthquake rupture progresses along the fault, or directivity, also affects the duration and intensity of shaking. The total time the shaking lasts is extended or reduced because the source of the earthquake waves is moving as it releases energy, similar to the what happens when sound waves are Doppler shifted.

CAN WE PREVENT EARTHQUAKE?

 In general we cannot prevent earthquakes from occurring. Preventing earthquakes would require some reasonable control over stress along faults. Engineers and scientists have proposed injecting fluids deep into the ground near active faults, allowing many small earthquakes to relieve stress rather than one large damaging natural event. However, many scientific and legal issues would need to be resolved before this could be happen; it isn't going to happen anytime soon, at least not in the U. S.

DO EARTHQUAKE OCCUR ON THE  MOON?

Quakes do occur on the Moon, but we call them moonquakes instead of earthquakes. The Apollo space missions emplaced five seismographs on the Moon; four recorded seismic activity until 1977. Although the Moon doesn't have multiple tectonic plates like the Earth, it does have a lithosphere which acts as a single plate. Thus the tectonic inter-plate earthquakes prevalent on the Earth cannot occur on the moon. However, the Moon does experience shallow intra-plate (interior of a plate) earthquakes. In addition, very deep quakes caused by tidal forces, meteroid impacts, and near-surface quakes caused by the heating and cooling of the Moon's surface occur regularly. Yosio Nakamura , a scientist at the UT Institute for Geophysics, is probably the world's leading authority on the seismic activity of the Moon.

DO OTHER PLANETS OR MOONS HAVE QUAKES?

            Yes, maybe. The Viking space mission placed a seismometer on Mars in 1976, but it never measured any quakes, probably because it was a very low-sensitivity instrument. Some of the surface features
observed on Venus, Io (a moon of Jupiter), and the icy satellites of the outer planets suggest that seismic activity might occur there. But for now we don't have seismographs in place to be sure.

GUESSES ABOUT EARTHQUAKE İN TURKEY

With  Marmara and Düzce earthquakes people wants to know the earthquakes which can happen in the future. But no one from goverment make an explanation . İt is certain that earthquakes will happen in 50-60 years which will be destructive but definitely that is not known by anyone . The technology in our day can warn us 5-6 seconds before an  earthquake.

            Dike stripes in Turkey is always active we learn this by the searches of SİSMİK-1 and SİSMİK –2 .And this is a signal of the earthquaje that we will have in future.

 

BECAUSE OF THE REASON OF THE DEATHS

The lost 2 earthquake show that deaths because of earthquake is very much in Turkey.The number of the deaths in the Marmara and Düzce earthquake are nearly 40 thousand and in the Erzincan earthquake which happend in 1939, there were deaths more than 55 thousands. And this shows us that , Turkey isn’t ready for earthquake we don’t know how to protect ourselfes.

            We are bcause of hots of deaths. The reasonsof death rations to be much:

·         Because of there isn’t enough pretection in indisturial districts , barrages , roads , pipe lines and tunnels . And these of things is a reason of deaths.

·         There must be “early warring machine “ in gas and electric system which are in the earthquake areas.Because these system arereasons of the biggest damage.

·         Big parts of deaths  is caused by uncaring people .The education before the earthquake warns people and decredse deaths.

·         There must be rescue teams in all the cities which is in an earthquake range

In earthquake we strong well made buildings have much more chance than the other buildings.And most of the deaths in earthquakes is caused by buildings which are not well made .To decrase the deaths in earthquake we should build strong buildings.

What should we do in close places is:

·         We should have a plan of things which we will do when earthquake is happening and after earthquake.

·         We should choose a meeting place after earthquake .

·         We should choose a place in home to protect  ourselves

·         We should cut electricity , gas and water.

·         The furniture which can tall should be sticked to the wall.

·         We should prepare an emergency bag.

DIKE STRIPE IN TURKEY

      A)Kuzey Anadolu Earthquake Girdle

            The dide stripe which is at the north of Turkey is liying west to east. It's lenght is 1500 km. It starts from Saroz Bay Gelibolu,depth of Marmara Sea ,İzmit Bay ,Adapazarı ,Duzce ,Gerede ,Merzifon ,Suluova , Erbaa ,Niksar ,Erzincan ,Erzurum and Van.This dike affect sokm arround of itself.The earthquake which we lived last was because of this stripe.

           B)Güney Doğu Anadolu Earthquake Girdle

        It is at the south of Turkey an ıt's from İskenderun to Van which shape is like abow .Hatay,Kahramanmaraş,Adıyaman,Maltya,Elazığ ,Bitlis and Van are an this dike stripe.this dike stripe joins kuzey anadolu dike stripe at Bingöl-Karlıova .Little earthquake happen this dike stripe.

           C)Batı Anadolu Earthquake Girdle

           It isn't straight.It lies an Gediz ,küçük and büyük Menderes Plains

.Ayvalık,Dikili,İzmir,Aydın,Denizli,Isparta ,Akşehir,Burdur are on this dike.It doesn't affectso much area.          

          

           If we search map of  Turkey about earthquake  there are five earthquake areas . 1. degree earthquake areas are Karadeniz , Güneydoğu Anadolu and Ege parts. 2. degree earthquake areas are around of 1. degree earthquake areas. 3. degree and 4. degree earthquake areas of Trakya Karadeniz coasts araund of İç Anadolu and south of G üneygoğu Anadolu parts.The areas which earthquake are less than the others are between Tuz Lake and Akdeniz coast.

            If we search we would understand that important cities are in 1. degree earthquake areas.On accound of this measure of death is Turkey too much in earthquake.

If we search map of  Turkey about earthquake  there are five earthquake areas . 1. degree earthquake areas are Karadeniz , Güneydoğu Anadolu and Ege parts. 2. degree earthquake areas are around of 1. degree earthquake areas. 3. degree and 4. degree earthquake areas of Trakya Karadeniz coasts araund of İç Anadolu and south of G üneygoğu Anadolu parts.The areas which earthquake are less than the others are between Tuz Lake and Akdeniz coast.

            If we search we would understand that important cities are in 1. degree earthquake areas.On accound of this measure of death is Turkey too much in earthquake.

WHAT IS THE SOIL BOIL?

In adapazarı hundreds of buildings sank 1.5 m. into the ground .Adapazarı the graund lipuefied. Because of this  buildings sank into ground . But these buildings have less damage than adjacant buildings which were on sails that didn’t liquefied. Soils liquefied which were along the Lake Sapanca and Lake Sapanca Hotel sank 0.3 m. into the ground . When earthquake happens the soils which liquefied doesn’t shake as hard grounds. These type of grounds shake as water.And buildings sank into ground.This is called  SOİLBOİL.