ငလ်င္တိုင္းတာနည္း အဆက္

   ၁၉၇၀ က Charles Richter  ပုံ

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Charles Richter တို႕က ေျမငလ်င္တိုင္းနည္းကိုတိုးခ်ဲ႕လိုက္လို႕၊(၂၀) ရာစုႏွစ္အလယ္ပိုင္းကစျပီးႏိုင္ငံေတာ္ေတာ္မ်ားမ်ားက

အဲဒီMomento magnitude scaleနည္းသစ္ကိုအစားထိုးသုံးလာၾကေပမဲ့

႐ုရွနဲ႕အေပါင္းပါႏိုင္ငံေတြကမူလကRichter နည္းကိုဘဲဆက္သုံးၾကတာ၊

The Richter magnitude scale (often shortened to Richter scale) is one of a number of ways that have been developed to assign a single number to quantify the energy contained in an earthquake.

The scale is a base-10 logarithmic scale. The magnitude is defined as the logarithm of the ratio of the amplitude of waves measured by a seismograph to an arbitrary small amplitude. An earthquake that measures 5.0 on the Richter scale has a shaking amplitude 10 times larger than one that measures 4.0, and corresponds to a 31.6 times larger release of energy.[1]

Since the mid 20th century, the use of the Richter magnitude scale has largely been supplanted by the moment magnitude scale in many countries. However, the Richter scale is still widely used in Russia and other CIScountries.

Richter magnitude scale – Wikipedia, the free encyclopedia

http://en.wikipedia.org/wiki/Richter_magnitude_scale

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Joseph Nye, the Science Guy( ေမာင္သိပ္ပံ) က ငလ်င္အေၾကာင္းကိုဟာသေတြနဲ႕ေႏွာျပီး

ဟန္ပါပါသ႐ုပ္ျပရွင္းလင္းသြားတာဟာ

 စိတ္ပါဝင္စားစရာေကာင္းျပီးလူတိုင္းလဲသေဘာေပါက္လြယ္တာပါ၊

ဆယ္လီစနစ္အေၾကာင္းနဲ႕အင္အားထုတ္လႊတ္ပုံဒိထက္မကျဖစ္ေၾကာင္းကို

ပလပ္စတစ္ျပားနဲ႕Graphမ်ဥ္းေၾကာင္းတို႕နဲ႕ေပၚလြင္ေအာင္ရွင္းျပတာ

Bill Nye the Science Guy – Earthquakes (richter scale) – YouTube

http://www.youtube.com/watch?v=1qbg7orb1lc

Uploaded on Jun 22, 2011

Bill Nye and earthquakes, quality entertainment.

  

ကမ္ဘာ့ေျမထုေတြဧရာမတိုက္ၾကီးေတြဟာတေနရာမွာဘဲ မလႈပ္မရွား

အျမဲတေစရပ္တည္ေနတာမဟုတ္ ေရကန္ျပင္မွာေပၚေနတဲ့Plateအခ်ပ္ျပားၾကီးေတြလို

တိုးေဝွ႕တိုက္မိေနၾကေၾကာင္းသ႐ုပ္ျပရွင္းလင္းတာပါ၊

ေျမငလ်င္တိုင္းSeismographကရိယာၾကီးကိုလက္ေတြ႕လိုက္ျပတာပါ

 ပင္လယ္ေရျပင္ေပၚမွာ “ေပၚ ” ေနသလိုေျမၾကီးေအာက္မွာ

Lava ေခ်ာ္ေရပူေတြရွိျပီး၊၄င္းတို႕အေပၚမွာ “ေပၚ”

ေနၾကေၾကာင္းကိုလိုက္ျပတာပါ

ငလ်င္စျဖစ္ရာ ငလ်င္ရဲ့ဇစ္ျမစ္တည္ေနရာ (ဗဟိုရ္ခ်က္မ)နဲ႕အတိမ္အနက္ကို

ဘယ္လိုရေအာင္လုပ္ၾကတာကိုေသခ်ာရွင္းျပတာ

Bill Nye the Science Guy – Earthquakes – YouTube

http://www.youtube.com/watch?v=2hKssFQdZ0k&feature=related

HowStuffWorks “How Earthquakes Work”

http://science.howstuffworks.com/nature/natural-disasters/earthquake.htm

In truth, however, our planet’s seemingly stable surface is made up of enormous pieces of rock that are slowly but constantly moving. Those pieces continually collide with and rub against one another, and sometimes their edges abruptly crack or slip and suddenly release huge amounts of pent-up energy. These unsettling events are called earthquakes, and small ones happen across the planet every day,…..

HowStuffWorks “Earthquake Facts”

http://science.howstuffworks.com/nature/natural-disasters/earthquake1.htm

Earthquake Facts

Technically, an earthquake is a vibration that travels through the Earth’s crust. Quakes can be caused by a variety of things, including meteor impacts and volcanic eruptions, and even sometimes manmade events like mine collapses and underground nuclear tests [source: Hamilton]. But most naturally occurring earthquakes are caused by movement of pieces of the Earth’s surface, which are called tectonic plates. ……

HowStuffWorks “How Earthquakes Work”

 

http://science.howstuffworks.com/nature/natural-disasters/earthquake2.htm

Plate Tectonics

The earliest documented earthquake occurred in China in 1177 B.C. But for most of history, people didn’t really have any idea what caused them — though they had some wild theories, such as the belief earthquakes were caused by air rushing out of caverns deep in the Earth’s interior. It wasn’t until the mid-1800s that scientists began to study and measure earthquake activity in earnest, using a device developed in Italy called the seismograph [source: USGS, Shearer]. Finally, in the mid-1960s, researchers in the United States and Great Britain came up with a theory that explained why the Earth shook [source: Silverstein].

The theory, called plate tectonics, is that the Earth’s crust, or lithosphere, comprises many plates that slide over a lubricating asthenosphere layer. At the boundaries between these huge plates of rock and soil, the plates sometimes move apart, and magma, or molten rock, comes to the surface, where it’s called lava. It cools and forms new parts of the crust. The line where this happens is called a divergent plate boundary…….

သာမန္ “သမ႐ိုးက်လႈပ္ရွား”Fault ကြဲအက္ပုံ 

လင့္ခႏွိပ္ျပီးဝင္ကာအဲဒီPlay အသီးကိုႏွိပ္ၾကည့္ပါ

HowStuffWorks “Faults”

http://science.howstuffworks.com/nature/natural-disasters/earthquake3.htm

Faults

There are four types of earthquake faults, which are differentiated by the relative position of the fault plane — that is, the flat surface along which there’s a slip during an earthquake.

In a normal fault (see animation below), the fault plane is nearly vertical. The hanging wall, the block of rock positioned above the plane, pushes down across the footwall, which is the block of rock below the plane. The footwall, in turn, pushes up against the hanging wall. These faults occur where the crust is being pulled apart, at a divergent plate boundary.

 “ေျဗာင္းျပန္လႈပ္ရွား”Fault ကြဲအက္ပုံ 

လင့္ခႏွိပ္ျပီးဝင္ကာအဲဒီPlay အသီးကိုႏွိပ္ၾကည့္ပါ

The fault plane in a reverse fault is also nearly vertical, but the hanging wall pushes up, and the footwall pushes down. This sort of fault forms where a plate is being compressed. A thrust fault moves the same way as a reverse fault, but at an angle of 45 degrees or less [source: USGS]. In these faults, which are also caused by compression, the rock of the hanging wall is actually pushed up on top of the footwall at a convergent plate boundary.

“ေဘးတိုက္လႈပ္ရွား”Fault ကြဲအက္ပုံ 

လင့္ခႏွိပ္ျပီးဝင္ကာအဲဒီPlay အသီးကိုႏွိပ္ၾကည့္ပါ

In a strike-slip fault, the blocks of rock move in opposite horizontal directions. These faults form when crust pieces slide along each other at a transform plate boundary. The San Andreas Fault in California is one example of a transform plate boundary.

With all these faults, rocks push together tightly, creating friction. If there’s enough friction, they become locked, so that they won’t slide anymore. Meanwhile, the Earth’s forces continue to push against them, increasing the pressure and pent-up energy. If the pressure builds up enough, it will overcome the friction, the lock will give way suddenly, and the rocks will snap forward. To put it another way, as the tectonic forces push on the “locked” blocks, potential energy builds. When the plates are finally moved, this built-up energy becomes kinetic.

The sudden, intense shifts along already formed faults are the main sources of earthquakes. Most earthquakes occur around plate boundaries because this is where strain from plate movements is felt most intensely, creating fault zones, groups of interconnected faults. In a fault zone, the release of kinetic energy at one fault may increase the stress — the potential energy — in a nearby fault, leading to other earthquakes. That’s one reason why several earthquakes may occur in an area in a short period of time……..

Primary Wave (P Wave) မူလလိႈင္းဂယက္ နဲ႕ Secondary Wave (S Wave) ဆင့္ပြါး ေနာက္ဆက္တြဲ လိႈင္းဂယက္ ေတြ

လင့္ခႏွိပ္ျပီးဝင္ကာအဲဒီPlay အသီးကိုႏွိပ္ၾကည့္ပါ


HowStuffWorks “Seismic Waves”

http://science.howstuffworks.com/nature/natural-disasters/earthquake4.htm

When you toss a pebble into a pond, it creates radiating waves in the water. An earthquake does the same thing with energy. When the plates fracture or slip, energy is released as seismic waves [source: USGS].

There are several types of seismic waves. Body waves move through the inside of the Earth. There are two types of body waves:

Primary waves (or P waves) are the fastest moving waves, traveling at 1 to 5 miles per second (1.6 to 8 kilometers per second). They can pass through solids, liquids and gases easily. As they travel through rock, the waves move tiny rock particles back and forth — pushing them apart and then back together — in line with the direction the wave is traveling. These waves typically arrive at the surface as an abrupt thud.

Secondary waves (also called shear waves, or S waves) are another type of body wave. They move a little more slowly than P waves, and can only pass through solids. As S waves move, they displace rock particles outward, pushing them perpendicular to the path of the waves. This results in the first period of rolling associated with earthquakes. Unlike P waves, S waves don’t move straight through the Earth. They only travel through solid material, and so are stopped at the liquid layer in the Earth’s core.

HowStuffWorks “Seismology”

http://science.howstuffworks.com/nature/natural-disasters/earthquake5.htm

Seismology

On the last page, you learned that there are three different types of seismic waves, and that these waves travel at different speeds. While the exact speed of primary waves (P waves) and secondary waves (S waves) varies depending on the composition of the material they’re traveling through, the ratio between the speeds of the two waves will remain relatively constant in any earthquake. P waves generally travel 1.7 times faster than S waves [source:

 

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Earthquakes 101 – YouTube

http://www.youtube.com/watch?v=VSgB1IWr6O4&feature=related

ေတာင္ပိုင္း ကာလီဖိုနီယာေျမငလ်င္ဌာနအၾကီးအကဲ ပါေမာက္ခProfessor Tom Jordanက ေျမငလ်င္အေၾကာင္းေမးျမန္းခ်က္ေတြကိုထိထိမိမိေျဖၾကားသြားတာပါ၊

တိုတိုနဲ႕လိုရင္းေရာက္ေအာင္စိတ္ရွည္ရွည္နဲ႕ရွင္းေနေအာင္ေျဖႏိုင္တာပါ၊

Prof. Tom Jordan – Featured User Profile – Videojug

http://www.videojug.com/profile/USEX0154

 Earthquake Facts (Earthquake Science)

http://www.videojug.com/interview/earthquake-facts

Welcome to Earthquake Country!

http://www.earthquakecountry.info/

Earthquake Facts

Tom Jordan (Director, Southern California Earthquake Center (SCEC)) gives expert video advice on: What is the probability of a severe earthquake striking a major city?; Where do earthquakes most often occur?; What are the most common earthquake myths? and more…

What is an “earthquake”?

An earthquake is any shaking of the ground – usually intense shaking of the ground – caused by either natural sources or by humans. The most common types of earthquakes are those caused by ruptures of geologic faults or earthquakes associated with volcanic activity.

What are the different types of earthquakes?

There are three major types of earthquake. Firstly, geologic earthquakes – sometimes called tectonic earthquakes – are caused by the rupturing of faults in the earth’s crust. There are volcanic earthquakes, caused by the movement of magma in volcanoes. Lastly, there are various types of earthquakes caused by man-made activities, for example, explosions or the collapse of large structures.

Can earthquakes be predicted?

Whether earthquakes can be predicted is a very difficult question for we seismologists to answer. Certainly, there are things that we can predict about earthquakes. For example, we know where earthquakes are going to occur: primarily on large geologic faults. We know how big those earthquakes might be. For example, on the San Andreas Fault here in California, we know earthquakes can be as large as magnitude 8. The difficulty is that we cannot predict when large earthquakes will occur with any kind of reliability or precision needed to warn communities of impending disasters.

What is the probability of a severe earthquake striking a major city?

The probability of a severe earthquake striking a city is typically very small, and of course that probability depends on which city you’re talking about. Some cities, such as Los Angeles, are in very geologically active regions where earthquakes are common. In those locations, the probability of an earthquake is higher. Some cities, like New York City on the east coast of the United States, are not in a geologically active region, and therefore the probability of an earthquake occurring is lower.

Where do earthquakes most often occur?

Earthquakes most often occur on the boundaries between major tectonic plates. The earth’s surface is broken into a dozen or so major plates, plus a number of smaller plates and those plates are moving with respect to each other. On the boundaries between two plates is where that motion occurs and that’s where we find the big earthquakes. For example, in California there is a major plate boundary between the pacific plate to the west and the North American plate to the east. The fault that marks that boundary is the San Andreas fault and that’s where we have some of the largest earthquakes in the continental United States.

What are the most common earthquake myths?

There are many earthquake myths. One of my favorite is the myth of “earthquake weather.” Some people believe that certain weather patterns are condusive to the occurrence of earthquakes, and there is no scientific evidence that this is the case. Another earthquake myth is that large regions like California might break off and fall into the ocean. Even the largest earthquakes produce motions along geologic faults of only about 1-2 meters–not nearly enough to submerge California. Another earthquake is that animals can sense earthquakes coming in advance. Although there are many stories of this sort, there is, again, no scientific evidence that animals can detect earthquakes in ways that humans cannot.

What is the “Foreshock”, “Aftershock”, and “Main Shock” of an earthquake?

A foreshock is a small earthquake that occurs before a larger earthquake. Aftershocks are small earthquakes which occur following a larger earthquake. Main shock is a term that is used to distinguish a large earthquake from its foreshocks or its aftershocks.

How long do most earthquakes last?

Earthquakes can last different periods of time depending on their size. Small earthquakes typically last only a few seconds. A large earthquake, such as the 24 earthquake which occurred in Sumatra, can last for many minutes.

 

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