Earthquakes (19540

Quakes and the destruction they cause have been reported from the time of man coming on Earth some earthquakes are minor called damage to mankind others are severe causing considerable damage 83,000 people lost their lives in the missina Italy earthquake of 198 1,000 people lost their lives in the Tokyo Yokohama earthquake in 1923 the Great China Quake took 200,000 lives the greatest disaster ever property damage generally amounts into millions of dollars a year from this cause earthquakes are very common there isn't an hour in the day or a day in the year when there isn't an earthquake somewhere over 10,000 earthquakes are registered each year most Do no harm or relatively little a machine measure the intensity and the distance of a quake is called a it records the shock waves sent from the earthquake's point of origin an earthquake sends waves through the Earth as does a pebble dropped in a body of water large buildings can be destroyed as the shock waves caused by great displacement or movement of the Earth's surface pass under them the greater the effect of the surrounding area the greater the distance at which it will be felt the shock waves radiate in all directions and a seismograph can register the waves and intensity on a revolving drum a scientist must be able to tell the difference between waves made by Nature and those made by men you can easily tell the difference between a blast and an earthquake a blast will be recorded by shorter distances and the earthquake by greater distances the blast radiates rapidly while a mild earthquake wave rate as also does a strong earthquake earthquakes send three different types of waves the arrow points to the spot seismograph is anchored to Solid Rock the H where the other Arrow points is the earthquake Center some waves go through the solid Rocks Under the surface of the Earth others go along the surface of the Earth and others travel through the top soil straigh you have heard an echo shock waves also cause echo or secondary waves these often cause a great deal of confusion but by interpreting the marks on the size mograph drum a scientist can tell exactly how far the source of the Quake is from his station but he cannot tell the direction thus the scientist draws a circle on the globe to show the distance as measured at his station a second station can do the same for station a third station drawing a similar Circle helps to pinpoint the exact location this is called triangulation you have all seen effects of earthquakes on the surface of the Earth irregular layers of rock are evidence of this phenomena layers of Twisted and bent Rock straa make the Earth crust weak these layers have been developed through heat and pressure on the surface and the interior of the Earth this weakness allows for faults in the Earth's crust fault is a point where a layer of rock splits and slides apart to give an up thrust on one side and a slide on the other by studying written history and plotting earthquakes we have learned where the major earthquake belts are one starts in Alaska and goes to the tip of South America along our West Coast there is another in the Far East and one cutting through the Mediterranean Sea Mountain areas indicate these earthquake belts another major cause of earthquakes is the dissolving of low rock strata through action of water limestone is one such Rock straa the up layers of the fall in areas these are usually mild earthquakes earthquakes are mostly caused by Earth faults a fault will generally have an up twist thus affecting a large area or TRS in the Earth are caused faulting we cannot stop these forces of nature we can build better buildings and warn people when a quake is liable to occur thus through constant experimentation we may someday be able to build homes to withstand the forces of nature that threaten us and we may be able to eventually live in comparable safety from the most of the destructive forces of nature