Earthquakes

Ivan Cukanić

Science 7B

2/24/2013

Earthquakes

Earthquakes are very common occurrences in nature.  Averagely 7 million earthquakes occur each year, but only a few of them produce damage.  The crust, the outer thin layer of our planet is composed of tectonic plates that are floating on a hot, melted liquid that is constantly circulating. While beneath the Earth’s crust, this liquid is called magma, but as soon as it is shot out of a volcano, it changes its name to lava. The circulation of magma makes the plates move. Earthquakes are caused by the movement of tectonic plates. The movement of tectonic plates also causes seismic waves that make tsunamis, volcano eruptions and much more. Seismic waves are not created just anywhere, but on the borders of these plates.

First, an earthquake is a sudden, rapid shaking of the ground, which is caused by subterranean rock breaking and moving. This subterranean rock is part of a tectonic plate that is constantly moving. “The underground location where the rock first broke apart or shifted is called the focus of the earthquake” (http://cse.ssl.berkeley.edu/lessons/indiv/davis/inprogress/QuakesEng3.html, 1995). Location on earth surface directly above the focus is called epicenter.  Energy is accumulated because of the moving plates, so when there is enough energy, it is released onto the surface in the shape of earthquakes.  If strong enough this energy release can make tectonic plates separate. Whole cities can be devastated by earthquakes. All of Europe, the west coast of South and North America, parts of Asia near India and the east coast of Asia are the most common places where earthquakes occur. This is because the boundaries of tectonic plates are on those locations. “Most of the largest earthquakes occur within the Pacific ‘Ring of Fire’, a horseshoe-shaped band of volcanoes and fault lines circling the edges of the Pacific Ocean” (http://www.trust.org/alertnet/crisis-centre/subtopic/earthquakes, 2009). Briefly, earthquakes are a destructive shaking of the ground caused by tectonic plates.

Also, waves caused by a movement of tectonic plates are seismic wave, which include longitudinal (P waves), transverse (S waves) and surface waves. P waves are the fastest ones, S waves are the most destructive ones and surface waves are a combination of longitudinal and transverse waves that travel through the surface of their medium.  Seismographs are machines that record these waves and warn us about upcoming earthquakes. When a seismograph records P waves that is a just a warning and there is usually no destruction, but when it records S waves, that means that the earthquake is already in session. However, when a seismograph warns us about P waves, it is only a matter of minutes before the destructive S waves come. If the location of the seismograph is on the border of the tectonic plates, there would be absolutely no time to prepare for an earthquake, for the distance the waves have to travel is short, so the P waves would barely outrun the S waves. Summarizing, there are three types of seismic waves: S, P and surface waves.

Third, the best way to protect ourselves and our city / town from earthquakes is through earthquake engineering. Earthquake engineering is the scientific field that concerns the damage done by earthquakes and how to stop it. One issue that they are solving is designing a building that can withstand seismic waves and not partially or completely collapse during a rare and very destructive earthquake or a common and not so destructive earthquake. They test out buildings through experimental or analytical/numerical assessment. Experimental assessment is the assessment of 1:1 scale models of buildings on a mechanical surface that shakes and simulates an earthquake. During the experiment, they record their observations and conclude what kinds of buildings are safer and more serviceable during and after the earthquake. Analytical/numerical assessment is when they try to design new buildings using beams, columns, beam-column joints, shear walls, etc. The only problem with making buildings with these accesories is that it would be very expensive and the economy of that country would probably weaken because of this, but later they would get the money back, for the buildings would endure even the most destructive earthquakes. Hence, there are two types of earthquake engeneering: experimental and analytical/numerical.

In conclusion, humans still have not found a way to warn ourselves or protect ourselves from very common and very destructive occurrences called earthquakes. Our warning system goes off just a few minutes before the earthquake, our buildings collapse and injure or kill people and we cannot save the injured people on time, for they are usually buried under pieces of concrete. But scientists are working on it and each day they come to an important conclusion, so step by step they will find a way to warn us on time and make endurable buildings.

Bibliography: 

http://nisee.berkeley.edu/bertero/

http://cse.ssl.berkeley.edu/lessons/indiv/davis/inprogress/QuakesEng3.html

http://www.trust.org/alertnet/crisis-centre/subtopic/earthquakes

http://www.ready.gov/earthquakes

Current Event

Urban Heat May Warm Faraway Places

Author of the article: Daniel Stone

Date published: 28th of January 2013

Source National Geographic

URL: http://news.nationalgeographic.com/news/2013/130128-climate-cities-urban-heat-island-atmosphere-science/

Every day tasks in a city produce very much energy, which is transformed into heat. This heat cruises around the air in the city and flows into the jetstream, so it spreads around the planet heating up villages. Big metropolises in America use up 42% of the annual global consumption. This means that humans are responsible for global warming. 

I enjoyed reading this article because it talks about a huge issue. Humans should find a way to stop energy from transforming into heat. Soon, I will not be able to ski, for snow will be very scearse. I hope that a majority of people will except the new life with machines that do not transform energy into heat.

Reflection on the Wave Experiment

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In the this experiment, my partner was Nikola. We used a plastic tray, two pipettes, a paper towel, modeling clay, cork and water. First, we dropped water in the center of the tray using pipettes and it produced circular waves that pushed the cork outwards. When there was one drop in the corner, it pushed the cork towards the opposite corner. When there was one drop at the end, it pushed the cork towards the other end. When there were two drops were close together in the center, they made a bigger wave. When there were two drops in the corner, again the wave was bigger and pushed the cork towards the other corner. When there were two drops at the end, the wave was bigger and pushed the cork towards the other end. If two waves going in opposite directions met, they went under/over the other wave. If a wave hit a barrier it bounced off and lost some energy. If a wave hit the side of the pan it bounced off. If a wave got to the paper towel, it would go under it. A wave would always go through the gap in between the barriers. The larger the frequency the more waves, the wave source produces in a second. The larger the amplitude the more energy the waves carries. 

Current Event

Outbreak notice

Malaria in Greece

By: Ivan Cukanić

Author of the Article: Center for Disease Control and     Prevention

Date Published: November, 24th, 2012

Source: Center for Disease Control

URL: http://wwwnc.cdc.gov/travel/notices/outbreak-notice/malaria-greece-sept-2012.htm

Although it is considered as an officially eradicated disease in Greece from 1974. with only  sporadic cases of malaria connected only to travelers from Africa and Asia, there are, day by day,  new cases of this mosquito spread disease. Attica, Karditsa, Laconia, Viotia, and Xanthi are regions of Greece affected by this dangerous disease. The Hellenic Center of disease control and also European CDC take part in thorough monitoring of new cases and organize better mosquito control, but also public information and education about malaria. 

Malaria is parasite disease transferred from an infected to a healthy person by mosquito bite. In the early stages of the disease, symptoms of malaria are very similar to banal viral infections with fever and chills, but if left unrecognized, it can even be fatal. With almost 500 million cases and 1 million deaths per year worldwide, it is one of the largest health problems in the world. It is very common in undeveloped and developing world regions, often in swamp areas which favor mosquito reproduction and multiplication. Malaria is a quite common disease in many parts of Africa, Central and South America, Asia, South Pacific and Eastern Europe.  It is recommended for all travelers to Greece to use insect ( mosquito ) repellent on exposed skin, to wear protective clothing and to spend time indoor in mosquito protected places. In case of travelling to an agricultural region of Eurotas, CDC recommends taking medicine prescription for disease prevention.  It is of great importance to take all fevers seriously during and up to one year after travel and to seek professional medical help as soon as possible. Malaria is a completely curable disease in case of prompt and adequate treatment.

I liked this article because it warns people about diseases they forgot that even existed in some parts of the world. If not prepared, you can get malaria and if you don’t recognize it, it can even kill you. This connects to science because it involves mosquitoes, protozoa and diseases. I think this site is reliable because it has “.gov” in the URL.

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NASA's Kepler Completes Prime Mission, Begins Extended Mission

Blog post by: Ivan Cukanić

Author of the article: Michele Johnson

Source: NASA

URL: http://www.nasa.gov/mission_pages/kepler/news/kepler_prime_mission.html

   Kepler is a space telescope that was launched into space on the 6th of March, 2009. It is on a mission to find planets we could live on that are similar to Earth.  Kepler made many discoveries with a variety of new techniques. One of its most famous discoveries is the "Kepler 22b", a planet which is in the habitable zone in its solar system. It has completed its 3 year long mission and now it begins an extended mission which will last four more years.

   I liked this article because it talks about new discoveries in space. I think Kepler is actually going to find Earth's "twin planet" on the extended mission, and I do hope that planet will be close, so we can travel to it quickly. I have learned from this article that we need to be patient in order to find revolutionary discoveries, for this space telescope's mission will last 7 years in total. This article also taught me that Earth is not a unique planet and that maybe there is intelligent life out there. I don't mean aliens from science fiction novels and movies, but something like humans. I believe in this article because its from NASA, and NASA is the most famous space research organization in the world. NASA's articles are written by scientists and educated, trustworthy people.

Dirt

Dirt

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(Reflection)

     I enjoy working with dirt because it relaxes me and it is fun. I especially love digging.

     If  the land of farmers was being taken here in Serbia, many families would become notably poorer and unhappier, especially if their only occupation was farming. I agree with Paul Stamets' analogy because we are ruining dirt and with dirt our whole planet including us humans, as a virus hurts its host and when the host dies the virus dies with it.
 
     We should take care about every piece of  fertile land by  preserving  it of any type of contamination and by cultivating policulture instead of monoculture on it. Wherever we can, we should  reduce areas covered by concrete and asphalt. I do think that if everyone tries their best to conserve dirt we will succeed. People usually think that its not important to try conserving dirt because nobody else is trying and its not enough for one person to try, but if everyone changes their opinion, we would have millions and millions of people trying their best to conserve dirt. Governments  should make a regulation to decrease monoculture cultivation and pesticide usage which would reduce the amount of ruined soil. They can also stimulate reforestation of some areas. Everyone should have in mind that dirt is a natural habitat for many animals. When dirt is contaminated or when it dries out, the animals will either die, or escape to another place, which isn't their natural habitat, causing the food chain to change, making some animals or plants extinct. This would destroy the balance of the whole ecosystem.
   
     After this film, I feel that I should encourage my family and other people to have their own gardens with a variety of plants and that everyone should have a place to leave organic material to become dirt. Now I know that monocultures damage dirt in many ways as well as different chemicals. If mankind continue to destroy dirt, there would be a shortage of food everywhere in the world.

SpaceX, NASA Target Oct. 7 Launch For Resupply Mission To Space Station

 Source: Nasa

URL:http://www.nasa.gov/mission_pages/station/main/spacex-crs1-target.html

The Falcon 9 rocket carrying the Dragon space shuttle is going to launch on Sunday, Oct. 7, in Florida. It's mission is to bring new experimenting materials to the SpaceX space station and bring the observations to Earth. The Arabidopsis plant's cell walls mutate in microgravity and it can nearly overcome gravity.