Question Introduction
The question that was selected as the topic for discussion in this work is “How did oceanographers figure out the physical nature of tsunami?” The importance of this question is proved by the numerous cases of tsunami that have been hitting Asia over the recent years (GITEWS, 2009). Accordingly, for us as students it is of crucial importance to know how tsunamis develop and how the oceanographers have managed to study the nature of tsunami. As well, it is necessary for us to know about the specific equipment used in tsunami research and the means of predicting tsunami and fighting its effects. Thus, the current paper starts with providing the background information on tsunami that can help introduce the topic to the wide audience. Next, the paper moves on to discussing the methods and equipment oceanographers used to study the nature of tsunami. Finally, the paper concludes with new challenges that appeared in the study of the physical nature of tsunami.
Tsunami Background Information
However, to study the tsunami research equipment it is necessary first to realize what tsunami is and how it is formed. Thus, Nelson (2009) defines tsunami as “a very long-wavelength wave of water that is generated by sudden displacement of the seafloor or disruption of any body of standing water”. Tsunamis are characterized by wave length, height, amplitude, and velocity. According to Nelson (2009), wave length is the distance between similar points of the wave; the concepts of tsunami wave height and amplitude are interconnected, as the height is the distance between tsunami’s trough and peak, while the amplitude of tsunami refers to the height of this wave above the level of the still water (Nelson, 2009).
Although scholars often refer to tsunamis as “seismic sea waves”, Nelson (2009) argues that such a definition is not appropriate because tsunamis can have other causes of emergence than earthquake and other seismic activities. The major natural reasons that cause tsunamis include earthquakes, volcanic eruptions, landslides, underwater explosions, and meteorite impacts (Nelson, 2009). Also, the phenomena called Drawdown and Run-up characterize the deceptive nature of tsunamis.
Nelson (2009) describes tsunami drawdown as a situation when the trough of the tsunami hits the coast prior to the peak of the wave. Usually it is perceived as the decrease of the sea level and is not associated with danger. However, instantly the peak of tsunami heats and usually people and facilities on the coast turn out to be unprepared for this. Thus, the consequences of tsunamis are rather hazardous, especially when regions facing the threats of tsunami fail to carry out preventive measures and citizens’ education in regard of tsunami safety rules (Borrero, 2005, p. 312; Liu, 2000, p. 2). Drawing from this, the research of the physical nature of tsunami has always been considered a vital need for the safety of the humanity and for saving of thousands of lives.
Account on Tsunami Studies
Needless to say, oceanographers paid considerable attention to the diligent study of the physical nature of tsunami. The first step in this process was the outline of the major areas of interest and establishment of the appropriate methodologies and sets of equipment to explore them. Of course, the initial stages of tsunami research were rather based on people’s impression and thoughts about the possible nature of the disaster, as well as observations of this natural disaster (GITEWS, 2009). Nevertheless, the detailed and focused research on tsunami waves became possible only when oceanography as a science received the powerful impact for its development after the immense technological progress of the 19th century. The advances in the oceanographic equipment allowed scholars not only get pictures and sound recordings of the ocean processes, but also get into the ocean depth and explore the bottom, its nature, and the composition directly (Liu, 2000, p. 8). This was a great achievement in the way of studying the physical nature of tsunami waves as far as direct study of the backgrounds in which tsunamis are generated cannot be replaced by any artificially created and laboratory research projects.
Further on, the data provided by GITEWS (2009) allow speaking of the more serious approach to tsunami research that is developed by scholars. GITEWS (2009) presents a detailed account on the methods of tsunami study and early warning used by the joint Indonesian and German team of scholars to protect the countries of Indian Ocean region from tsunamis. The study of the nature of these destructing waves, according to GITEWS (2009), involved the use of modern oceanographic equipment together with the satellite, both earth-based and orbital, technology. Accordingly, the major approaches that scholars used to go about the study of the physical nature of tsunami included the seismological study, sound recording procedures (Liu, 2000, p. 10), satellite communications processes, and the systems of warning the regions potentially subjected to tsunami dangers (GITEWS, 2009).
Oceanographic Equipment Used for Tsunami Research
Naturally, the oceanographers had specific equipment in their disposal to study the physical nature and causes of tsunami waves. This equipment ranged from the simplest computer programs to monitor the development of tsunamis to the complex satellite technology used for both tsunami study and development of the early warning systems (GITEWS, 2009). For example, Liu (2000) discusses the wave research equipment that consists of the wave tank and the wave generator that allowed the oceanographers to study waves in a three-dimensional large research facility and understand the physical nature of tsunami (p. 5). The essence of this equipment laid in the creation of the artificial environment where tsunamis could be generated by the earthquake and volcanic eruption simulations without the danger for the people and facilities around (Liu, 2000, pp. 6 – 7).
Needless to say, such research did not provide all the information about tsunami’s physical nature that the natural study would provide, but at least it allowed scholars to make assumptions about the tsunami generation processes and possible ways of reaction towards tsunami threats (Liu, 2000, pp. 6 – 7). Further on, NOAA (2009) singles out a number of other equipment pieces including the computer systems of image modeling of the ocean bed and the scholarly surveys of oceanographic and seismic data that widened oceanographic knowledge on tsunami. As well, the two kinds of bottom imaging equipment were of great use for oceanographers including the TV and sound-generated imaging systems (NOAA, 2009). Water depth sounders and bottom samplers also provided considerable information about the physical nature of tsunami.
Finally, oceanographers used seismic and land-surveying devices together with tide gages installed in harbors to study the physical nature of tsunami waves (NOAA, 2009). Used in conjunction with the satellite technology like the GPS Altimetry Stations and Buoys argued about by GITEWS (2009), these pieces of equipment allowed oceanographers to not only study the physical nature of tsunami waves, but also prepare certain means of warning against tsunamis. As the experience of Indonesia showed in 2004, the warning system might have been rather useful in that case. Therefore, the use of oceanographic equipment to study the physical nature of tsunami contributes not only to the development of oceanography as a science but to the process of protecting the mankind from the threats of tsunami waves.
Results of Research on Physical Nature of Tsunami
As a result of this research work, oceanographers have managed to find out the considerable amount of data that characterize the physical nature of tsunami. For example, one of the basic facts about tsunami waves is, according to Nelson (2009), that the average tsunami wave length exceeds the average length of an ordinary ocean wave almost five thousand times and reaches the maximum of 500 kilometers (Nelson, 2009). Further on, oceanographers have noted that the height and the amplitude of tsunami waves depend upon the nature and the power of the tsunami-causing factor, while the velocity, i. e. the wave speed, often reaches the level of 950 km/h, which exceeds the ordinary ocean wave speed 10 times (Nelson, 2009).
Oceanographers also managed to dismantle the myth about tsunamis’ being produced by the seismic activity of the ocean bottom only. The research on the physical nature of tsunami revealed that apart from underwater earthquakes, tsunamis can be generated by volcanic eruptions, explosions, landslides, and effects of meteorite crashes into the ocean bottom. According to Nelson (2009), volcanic eruptions become the causes of tsunamis if the pyroclastic flows are rather powerful and able to displace large masses of water so that the latter should hit the coast. The point about the meteorite effects and underwater explosions is the same, as any stress of the water masses causes the latter to move. Combined with the depth of the water, the direction of the currents, and wind, the displaced water mass starts moving abruptly and acquires speed in transit to achieve the destructive power on reaching the coast. Finally, oceanographers nowadays refer to tsunamis as shallow-water waves, which means that tsunamis have small ration of wave length and depths and the deepest waves, which differs tsunamis from ordinary ocean waves caused by wind blowing over the ocean surface (Nelson, 2009).
New Questions on the Topic
However, after oceanographers had managed to answer the question about the physical nature of tsunami waves, a number of other related questions appeared for further scholarly consideration. For example, NOAA (2009) stresses the weakness of oceanography in temporary inability to identify the precise cause of tsunami in case if two or more factors can be the possible causes. When a tsunami happens in a region characterized by a high earthquake risk and a possibility of either volcano or other underwater explosions, there is currently no oceanographic equipment to state which one was the actual tsunami cause. To be more succinct, the new related questions are:
- How a precise cause of tsunami can be identified?
- Is tsunami possible in regions not displaying any of the above listed tsunami causing factors?
References
Borrero, J. (2005). Field Survey of Northern Sumatra and Banda Aceh, Indonesia after the Tsunami and Earthquake of 2004. Seismological Research Letters, 76(3), 312 – 320.
GITEWS. (2009). Tsunami Early Warning System. Web.
Liu, P. (2000). Report for a National Science Foundation Workshop for Tsunami Research Facilities. Cornell University, 1 – 10.
Nelson, S. (2009). Tsunami. Web.
NOAA. (2009). Tsunami Research. Web.