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Natural and Technological Hazards

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Natural and technological hazards encompass threats to human life, property, and environment originating from natural causes or technological impacts. Besides the loss of life, these threats lead to adverse effects such as injuries, illnesses, birth defects, destruction of property, and disruption of economic activities. Natural hazards such as volcanic eruptions, storms, hurricanes, and earthquakes occur without being triggered by human factors or involvement. On the other hand, technological hazards are those threats caused by advancement in technology or wrong use of technological resources by man. Technological hazards include industrial pollution, toxic waste emission, chemical spillages, transport accidents, and nuclear power meltdown. Some technological hazard may be triggered by man’s actions or sometimes just occur naturally both of which causes serious injuries and even death. Some are how the hazards occur and ways to prevent them and others are how to deal with them when they occur. This paper presents an annotated bibliography of five peer-reviewed articles on various natural and technological hazards. All the papers explain the effect that natural disasters have on populations and how the information can be useful in implementing changes.

Terry, J. P., & Goff, J. (2013). One hundred and thirty years since Darwin: ‘Reshaping’ the theory of atoll formation. The Holocene, 23(4), 615-619.

Charles Darwin’s work on atoll formation in the 18th century was met by opposing ideas and major criticism from all angles but his subsidence theory of atoll formation is offering good insights on oceanic activities almost 18 decades later. In this paper, James P. Terry and James Goff acknowledge the good foundation laid by Darwin in understanding tsunami hazards and other oceanic activities. However, the duo finds fault with Darwin’s allusion to the common circular and elliptical morphology of atolls, when many studies confirm that most of them have irregular morphologies. Far from explaining the diversity of atoll shapes, the theory explains what is popularly referred to as tsunamigenetic sources, which make up a good set of information in understanding the impacts of tsunami hazards.

Darwin’s subsidence theory of atoll formation posits that atoll reefs are formed as a result of subsidence of volcano which leaves circular or elliptical features when they subside. Although this idea was criticized, Terry and Goff highlight some of the various works that provide “reef core dating evidence” that several atolls have actually subsided thereupon substantiating Darwin’s theory. The paper also provides new information on how volcanic subsidence affects tsunami hazards. In this regard, as the volcanoes subside, there is movement of landslides down the tectonic plate which causes imbalance and shaking of the plate. The importance of submarine landslides is well established especially in the context of actively-growing volcanoes that are experiencing collapse of the flanks as the landslides moves downwards. The ‘stellate’ shapes of many oceanic volcanoes are explained by the giant landslides as they move downwards during subsidence. With this information, it turns out that high sea cliffs are formed as a result of erosion of landslide walls and not a product of marine erosion as suggested by scientists previously. Another model by a scientist called “null” was developed recently from the work of Darwin that illustrates how a volcanic island can completely vanish as a result of successive flank collapses. The collapsing of the flanks and subsidence of the volcanoes causes a disruption to the oceanic ground. The movements are said to cause waves in the ocean originating from the ocean floor and this causes the tsunami.

Perhaps a major dent in Terry’s and Goff’s work is their frequent reference to their 2011 paper, “Evidence of a previously unrecorded local tsunami, 13 April 2010, Cook Islands: Implications for Pacific Island countries.” For instance, they cite the paper to substantiate their claim that several Pacific Ring of Fire sources expose the island nations in the Pacific region to tsunamis. Further, they use the same source to counter this claim when they could have found the information in other scholarly articles. Nevertheless, this paper presents more insights and underlines the need for more research on subsidence theory to help save lives and property.

Terry, J. P., Winspear, N., & Cuong, T. Q. (2012). The ‘terrific Tongking typhoon’of October 1881–implications for the Red River Delta (northern Vietnam) in modern times. Weather, 67(3), 72-75.

One of the results of these natural hazards is the typhoon disaster which caused deaths and destruction of property in northern Vietnam. The young port town of Haiphong was entirely swept away, whilst terrible floods devastated the surrounding low-lying delta (Marks, D., 1992). The storm started slowly in Philippines and by the time it was reaching northern Vietnam it had gained very high intensity to blow away ships and destroy buildings. The typhoon is suspected to have split into two whirlwinds after passing china in 2nd October hence the high intensity. After further research other suggestions have since arose: migrating tropical storms have been known to merge, but it is physically improbable for a typhoon to split into two separate typhoons (Marks, D., 1992). For this reason, it is believed that after 3 October the actual track probably laid somewhere in between the two tracks originally suggested by Dechevrens. Supporting evidence is that anticlockwise wind circulation around the eye would have driven large waves against the Tonkin coastline and pushed the storm surge up branches of the Red River towards Haiphong, so leading to the wide- spread flooding that was experienced in the low-lying delta. The typhoon caused several miseries to the people and destroyed the environment in a number of ways. Augmented by torrential rains, rushing floodwaters inundated rice fields to depths of three or four meters. Swift currents destroyed Haiphong’s buildings, drowning many people and leaving thousands homeless; even in houses six kilometers distant from the seashore, water rose to 1.8 meters. As if to complete the devastation, the fierce winds continued to strengthen and reached their full force the same evening, around 1830h, snapping trunks and tearing trees from the ground (Marks, D., 1992). Although it is probably correct to say that the 1881 Tonkin typhoon does not deserve its ignominious rank as the third-deadliest tropical storm in history, it was nevertheless a destructive event that inflicted a dreadful toll in human life. Typhoon characteristics significant in the devastation were its relatively high intensity coupled with an unusual northward-curving track into the Gulf of Tonkin, which avoided disruptive land influences en route to the Red River delta. The typhoon should therefore be dealt with by all the countries in the world and future occurrence to be maintained with a lot of preparedness so that people don’t lose lives in that tragedy (Marks, D., 1992).

An area that is still more vulnerable to typhoon is the bay of Bangkok. Bangkok together with other areas was done a study on to determine the extent of typhoon vulnerability. At the head of the Gulf of Thailand, the subsiding Chao Phraya delta and adjacent low-lying coastlines surrounding the Bay of Bangkok are at risk of coastal flooding (Pentz, C., 1995). Although a significant marine inundation event has not been experienced in historical times, this work identifies coastal depositional evidence for high-energy waves in the past. On Ko Larn Island in eastern Bay of Bangkok, numerous coastal carbonate boulders (CCBs) were discovered at elevations up to 4+ m above sea level, the largest weighing over 1.3 tones. For the majority of CCBs, their certified appearance bears testimony to long periods of immobility since original deposition, whilst their geomorphic settings on coastal slopes of coarse blocky talus is helpful in recognizing lifting (saltation) as the probable mode of wave transport. In the absence of local tsunamigenic potential, these CCBs are considered to be prehistoric typhoon deposits, presumably sourced from fringing coral reefs by high-energy wave action (Pentz, C., 1995). Application of existing hydrodynamic flow transport equations reveals that 4.7 m/s and 7.1 m/s are the minimum flow velocities required to transport 50% and 100% of the measured CCBs, respectively. Such values are consistent with cyclone-impacted coastlines studied elsewhere in the tropical Asia–Pacific region. Overall, the evidence of elevated carbonate boulder deposits on Ko Larn implies that typhoons before the modern record may have entered the Bay of Bangkok. The recurrence of a similar event in future would have the potential to cause damaging marine inundation on surrounding low-lying coastlines (Pentz, C., 1995).

The earthquake that occurred on 11th March 2011 in Tohoku area in Japan was devastating.  The epicenter was estimated to be around 70 kilometers east of Oshika Peninsula.  The hypocenter was about 30 kilometers underneath the water surfaces. It occurred in Tohoku region which is found of the coast of Japan. The tectonic plate boundary that was involved in this earthquake was the Okhotsk tectonic plate and the Pacific plate (Sutton, G. 2011). The focal depth of Tohoku earthquake was that the plates moved upwards to level of 30 meters. The area covered by the slip of the plates was 300 kilometers long and approximately 156 kilometers wide. The earthquake also reached a magnitude of 9.0. The pacific plates also moved westwards at a speed of 83 millimeters per year.  Scientists have established the faults that made Tohoku earthquake and tsunami as zone of subduction between the Pacific and Eurasian plates.  The slippery nature of Tohoku plates contributed to release of great waves with devastating effects. The slippery nature of the plates made it possible for them to slip for unexpected level of 50 meters. The unexpected heights made it possible for the plates to release of high level energy causing destruction on the earth’s surface and leading to tsunami.  The thin nature of the area between Eurasian and Pacific plates also posed a threat. The shallow slips makes it possible for a mega thrust and this sudden release of energy could have contributed to development of tsunami (Samuels, R. 2013).

The displacement level of the Tohoku earthquake was above the Hypocenter. The moment the earthquake hit the east coast of Japan high levels of sea-floor movements were observed. The sea-floor movements were responsible for the events that occurred above the focal region. Using the Global Positioning System (GPS), the displacement level was 20 meters of horizontal displacement. Studies conducted also indicate that the earthquake resulted to displacement of 5 to 20 meters toward ESE. This also led to displacement of about 3 meters upwards.  The displacement near the epicenter was higher, about 24 meters in reference to the ESE. At the epicenter, upward displacement level was also recorded about 3 meters upward. The horizontal movement was also four times at MYGI in relation to movement detected on land.  The displacement indication suggested the estimated 20 to 30 meter level which was estimated as a possibility.  This possibility was not realized since; slip on terrestrial plate should be greater as compared to displacement on the sea floor (Pentz, C., 1995).  

Study conducted on Tohoku region in Japan indicates that there is very low frequency of earthquake affecting the area. The study indicated that there is reverse faults mechanism which has compression axis in the east and west direction. Study between 2005 and 2013 also revered that slip area of Tohoku earthquake was detected even before the earthquake occurred. Other regions near Tohoku had their slippery plates activated after the earthquake. This change in activity of the plates in Tohoku and the surrounding regions indicated that before and after the earthquake there was redistribution caused by change in cosmic order.

Tohoku earthquake recorded magnitude of 9.0. Initially the earthquake recorded a magnitude of 8.9 but was revised to 9.0. The intensity of the earthquake was felt by shaking effect on the earth surface. The shaking rhythm was characterized by ground motion and it was felt at multiple locations in Japan.  The phenomenal shock buildings and led to massive destruction of infrastructure. The ground motion felt appeared to be running parallel to the subduction trench. The aftermath of this earthquake and tsunami were minor ground motions. The minor tremors were about 262 and affected the offshore region about 500 kilometer radius (Sutton, G. 2011).

The hazard effects of any earthquake are greatly determined by the strength of the earthquake. The main dangers resulting from seismic activities are: – tsunami, ground motion, liquefaction, landslides and rock fall. Tsunami is long oceanic waves that are caused by sudden strong displacement of seawater. Ground motion involves the shaking of the earth surface causing destruction of properties, death and severe damage of dams and infrastructure. Landslide is as a result of ground shaking destabilizing the steep slopes. The seismic hazard that resulted from Tohoku earthquake was; ground shaking, landslides, fire, flooding and tsunami. Tohoku earthquake resulted into a powerful tsunami that reached waves of 40.5 meters in Miyako. The resulting tsunami also affected areas of Sendai and Honshu. This tsunami generated waves that were could be detected by GOCE satellite (Philbrick, N., 2004).

 Destruction caused by the earthquake was very extensive in japan. The official report indicated that 15,893 people were confirmed dead, 6150 were injured and close to 2,570 people were missing and approximately 230,000 people were displaced from their homes. The earthquake also caused massive destruction of buildings. Approximately 127,300 buildings collapsed and roughly about 1100,000 other were damaged partially or greatly but not to level of collapsing. Heavy destruction was also affected the infrastructure. Roads and railways were destroyed and left in bad state of repair. Electricity power grid was also hit (Philbrick, N., 2004). This resulted to majority of households to lack light. The resulting tsunami caused nuclear accidents. Level 7 meltdown was initiated in three nuclear plants. The resulting implication was evacuation of thousands in the surrounding areas and power generators were taken down. There was also significant economy setback that resulted. Destruction of key industries in Sendai city has great impact to the economy. The investors suffered losses; the public suffered job losses while the government also experienced loss of revenue. The financial figures indicate that close to US$14.5 billion and US$34.6 billion was lost. The cost of rebuilding the affected region and compensating the affected would also be very high. According to World Bank, this was the costliest disaster in history. It projected that the disaster led to a massive US$235 billion in relation to economic loss (Philbrick, N., 2004).

In conclusion typhoon has affected the world in a great way causing suffering and destruction of properties. The myths have just come to worsen the situation since people don’t have the right information about prevention and management. It is therefore right if people were to be educated and given more information about typhoon and its destructions.

 

 

 

 

 

 

References

Bobrowsky, P. (2013). Encyclopedia of natural hazards. Dordrecht: Springer. 

Geohazards Revealed by Myths in the Pacific: A Study of Islands That Have Disappeared in Solomon Islands. (2006). 鹿児島大学.

Marks, D. (1992). The Beta and advection model for hurricane track forecasting. Washington, D.C.: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Weather Service, National Meteorological Center ;.

Pentz, C. (1995). Hurricane track. Pretoria: Symbol. 

Philbrick, N. (2004). Sea of glory: America’s voyage of discovery : The U.S. Exploring Expedition, 1838-1842. New York: Penguin Books. 

 

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