One of my recent assignments was to write a report in essay format about tsunamis and tsunami detection.

Adrian 7A

Due March 1st

Early Warning: Tsunamis

            In 2004, a giant wave hit 14 countries including Indonesia, Sri Lanka India, Thailand and many more. In Sri Lanka alone, it destroyed 100,000 homes and demolished two thirds of the fishing fleet. What was this “giant wave,” and what caused it? Is there anything that can be done to prevent them? In this report I will cover three different branches of the topic of “giant waves”: what they are, how they are detected, and some notable or historical ones.

            The giant wave that I described in the first paragraph was a tsunami. The word tsunami is defined by Princeton.edu as “a destructive sea wave caused by an earthquake or volcanic eruption”. In other words, a tsunami is a large, powerful wave that was created by an undersea earthquake or volcanic eruption. They can also be caused by landslides and even explosions from undersea bomb tests. More specifically, the waves are created when lots of water is displaced because of the earthquake, volcanic eruption etc. For example, during an earthquake a tectonic plate can “flip up” because of pressure from another tectonic plate. However, when it “flips up”, it displaces, or moves a lot of water out of the way. The water is moved at great force, which forms the tsunami. One interesting fact is that tsunamis start out with a very long wavelength and short amplitude, which means that they are hard to detect visually out at sea and are long and flat. However, as they move closer to shore their wavelength decreases and the amplitude increases, which makes the waves taller and easily detectable.

Because tsunamis are caused by nature instead of humans (except for explosions), they are not preventable. However, they are somewhat detectable, so humans can get an early warning and escape the tsunami. One method that is used to detect tsunamis is through the use of seismic gauges which detect the earthquakes that can cause tsunamis. However, not all earthquakes lead to a tsunami, which means that a seismic gauge’s readings wouldn’t always be useful. To predict a tsunami, there are two general types of detectors that are the most used. “Pressure recorders,” which detect the weight of all the water above it, and “tide gauges”, which are measure the height of the sea level from the sea floor as well as other conditions. The pressure recorders look for a dramatic increase in total weight of the water above it. If a large increase is detected, it probably means that there is a tsunami above it. The tide gauges have an extremely long cable attached to the seafloor, all the way up to the buoy. The cable is used to detect the distance of the sea level from the sea floor. When there is a large increase, it means there is probably a tsunami. In that way, the two devices are similar. Both of these devices are used to detect a tsunami from far out, where the tsunami is difficult to detect. As a tsunami approaches the coast, it “sucks in” the water from the coast (in other words, the water will retreat), so a tsunami is easily detectible then, although it is at the last minute. As a final word, there is no guaranteed-to-work method of detecting tsunamis, and so tsunamis will continue to be a problem in the foreseeable future.

The most famous tsunami in history is surely the 2004 tsunami in Southern Asia which was mentioned in the first paragraph. It killed more than 150,000 people, but more than $7 billion dollars were pledged to be donated. Interestingly, a BBC article from 2005, a year later, stated that there was a shortfall of over $4 billion of the money that was pledged to be donated. The earthquake that caused the tsunami was 9.1 on the Richter scale, which makes it the third largest earthquake ever recorded, behind earthquakes in Chile and Alaska. Another notable tsunami was the 1999 Tsunami in Turkey, which was caused by a 7.6 level earthquake, and killed 17,000 people.

An additional notable tsunami was the 2006 tsunami in island of Java. This tsunami only claimed 500 lives, which is small compared to other tsunamis, but it was significant because it took place a year and a half after the tsunami in Southern Asia, yet it was not detected early enough to give the residents of Java time to evacuate. This showed the failure of the network of tsunami detectors that was built after the 2004 tsunami. Since then, more pressure sensors, seismological stations and other tsunami detecting hardware have been built.

To conclude, tsunamis are interesting but unfortunate natural disasters. They are often difficult to detect, and they have the power to kill thousands of people, as evidenced by the 2004 earthquake in Asia. They are out of our power like any other natural disaster, but with developing technology, our ability to detect them has gotten much better. Although it won’t come soon, maybe someday we’ll live in a world where tsunamis are detected days ahead of their arrival, and they won’t kill people anymore because all people would have been evacuated.

Sources:

2005, February. "2004 Indian Ocean Earthquake and Tsunami." Wikipedia, the Free Encyclopedia. Web. 28 Feb. 2011. .

BBC. "BBC NEWS | Asia-Pacific | Tsunami Aid Shortfall over $4bn." BBC News - Home. 18 Mar. 2005. Web. 28 Feb. 2011. .

Princeton. "Definition of Tsunami." World Net Web from Princeton. Web. 28 Feb. 2011. .

Columbia Encyclopedia. "Tsunami - Credo Reference Topic." Credo Reference Home. Web. 28 Feb. 2011. .

"Famous Tsunamis · Mega Tsunamis." Astrology Weekly - Astrology Articles and Information Updated Weekly. Web. 28 Feb. 2011. .

"BBC NEWS | Science/Nature | Indian Ocean Tsunami Warning System." BBC News - Home. 23 Dec. 2005. Web. 28 Feb. 2011. .

Smith-Spark, Laura. "BBC NEWS | Asia-Pacific | Indonesia Tsunami System 'not Ready'" BBC News - Home. 19 July 2006. Web. 28 Feb. 2011. .

"BBC NEWS | Asia-Pacific | Tsunami Aid: Who's Giving What." BBC News - Home. 27 Jan. 2005. Web. 28 Feb. 2011. .

Side note: I think my fingers are tired of typing T's before S's now. It feels so unnatural.

Right before the break, I started this lab with Jan and Brin. Jan was sick but Brin and I managed to complete the test before break. I did the full writeup during break, but as of writing I don't have my groupmates' work. SO here is my completed lab:

Adrian, Brin and Jan

Due Feb. 21, 2011

Locked vs. Free Seismogram Paper in a Custom Seismograph

I.  GUIDING QUESTION: When creating a custom seismograph, is it better to have the paper that the seismogram will be recorded onto locked into place while the ground below it moves, or is it better to have the paper loose and being dragged forward slowly?

II.HYPOTHESIS:  
Adrian’s Hypothesis: I think that it is better to have the paper locked into place on a moving platform, because if the paper was lose, it might resist the moving platform’s movement because of inertia and inaccurately record the moving platform’s movement.
Brin’s hypothesis:
Jan’s hypothesis:

III.  Exploration:
         Materials

1. Marker.
2. Many blank papers.
3. String.
4. Around 5 one Meter Sticks.
5. Masking tape.
6. Rubber bands.
7. About 15 Large metal washers that will be used as weights.
8. Scotch tape.
9. A large table
10. A cabinet or piece of furniture adjacent to the large table that isn’t connected to the large table and doesn’t move easily.

         Procedure

1. Sturdily tape or rubber band together 4 one meter sticks.
2. Stand this contraption up vertically next to your cabinet/piece of furniture, and tape the meter stick contraption tightly onto the cabinet/piece of furniture sing masking tape, in multiple locations for extra strength.
3. On the top of the meter stick, lie down a meter stick face down, so that about 15-20 cm of the meter stick is on one side, and 80-85 cm is on the other. The short side should be on the far side of the table, and the long side should be at least 30 cm over the table. Secure the single meter stick on with lots of masking tape. Now you should have built something that looks like a crane attached to a cabinet/piece of furniture.
4. Make two bundles of about 7 or more stacked metal washers, and tape them together using masking tape. Place them on the small side (the 15-20 cm side) of the top of the “crane”, and tape the bundles onto the surface of the meter stick so they are stable. Your “crane” now has weights that will help it remain stable and counteract the weight that will be placed on the long end of the crane.
5. Cut a piece of string (the string’s needed length depends on how high the top of the long end of the crane is over the table, but I recommend around 75 cm to give yourself enough room if you need it), and fold it in half.
6. Using that folded string, tape the end that is folded onto the tip of the long side of the “crane”. Trim the ends of the other side so they are both of equal length, and are a few centimeters above the surface of the table.
7. Tape a marker top-down to the suspended strings, so that the tip of the marker is barely touching the tip of the table.
8. On the middle of the marker, tape one metal washer (the same as you used before) to use as a weight that stabilizes the marker.
9. Tape down two pieces of paper horizontally next to to each other under the marker, so the marker has one long paper path to travel on. This is for test where the paper is fixed into place.
10. For the other test, tape together two pieces of paper, but do not tape them down to the table.
11. For the non-fixed-paper test, tape together 2 sheets of paper and as the table is being shaken back and forth but not down, have someone slowly slide the paper down.
12. For the fixed-paper test, shake the table as strong or lightly as you like, with variation for 30 seconds while slowly moving the table to the side at a consistent rate. (Note if you can’t fit 30 seconds of earthquaking on two papers, just add more papers.)

IV.  RECORD & ANALYZE
           Data Tables: Pictures of our seismograms:

          
           Analysis of Data:  
Adrian’s analysis: The first picture shows the seismogram we produced with the non-fixed paper method. The method failed to produced accurate and reliable results. We deemed this method a failure, as indicated by the text in the picture. The second picture showed our second method, where to paper was fixed into place. Although this method wasn’t all that reliable either, it was much more reliable than the first method and the results were inherently better. You can see we tested a “strong earthquake” by shaking the table very hard on the top (the left side) and we tested a “lighter earthquake” by shaking the table less hard on the bottom (the right side). In other words, you can see accurately when we were tested either hard or weaker earthquakes in the second picture, but you can’t really tell when there was a hard or weak earthquake in the first picture. That’s why we deemed our second method a “WIN!”. I believe that the second method was better than the first because when the paper was loose and not fixed into place, it didn’t move when the table did, and it also sometimes drifted to the side and had other off quirks that interfered with the reliability of the data. However, when the paper was taped to the table, it moved with the table, and never drifted off the the side, which led to better and more reliable data.
Brin’s analysis:
Jan’s analysis:

V.  Concept Acquisition (CONCLUSION):  
Adrian’s Conclusion: My guiding question was: “When creating a custom  seismograph, is it better to have the paper that the seismogram will be recorded onto locked into place while the ground below it moves, or is it better to have the paper loose and being dragged forward slowly?”. In our experiments, I found that it was better to have the paper locked into place while the ground below it moves. It is that way because if the paper isn’t locked into place, it doesn’t move while the ground below it moves (it doesn’t move because of inertia), and the paper sometimes drifts to the sides, both of which make the seismograms from the non-fixed-paper seismograph less reliable. That is pretty much what my hypothesis stated, so my hypothesis was correct.
Brin’s conclusion:
Jan’s conclusion:

VI.  Concept Application (FURTHER INQUIRY):    
Adrian’s Further Inquiry: In this lab, my data from the custom seismographs wasn’t very reliably valid by usual scientific standards, but I found that it is incredibly difficult to make your own seismograph that reliably produces valid data. By our own custom seismograph reliability standards, our second test was acceptably reliably valid, but our first simply was not. The biggest reason that the data from the first test wasn’t reliably valid was the same thing that I was writing the whole lab about: the first test’s paper didn’t move with the paper and often drifted to the side.
Brin’s further inquiry:
Jan’s further inquiry:

Extra stuff: Photos and video of our setup: