To What Extent Could The Sichuan Earthquake Be Regarded As A Man-made Disaster?

To what extent could the Sichuan earthquake be regarded as a man-made disaster? (40 marks)

The extent to which the Sichuan earthquake of 2008 can be considered a man-made disaster is a contentious topic. Seismic activity is usually the result of natural factors but is often impacted upon by human interference, either in the form of additional cause, or mitigation of the hazard. An earthquake is the release of stored elastic strain energy as seismic waves and heat, driving the propagation of fractures along a fault line. Human factors include those that have the capacity to trigger such release of pressure, and those that offer modification of the hazard. An earthquake only becomes a 'disaster' if it greatly impacts upon human systems; all 'disasters' must have an element of anthropogenic cause in order to gain such descri ption. This essay will examine the physical and human factors that are thought to have contributed to the devastation caused by the Sichuan earthquake (2008).

Although it is thought that human factors played a part in causing the 7.9 Mw earthquake on the 12th of May 2008, it is an indisputable fact that there would not have been an earthquake without natural plate movement and thus a build up of stress. The Indo-Australian plate is moving North at a rate of 30mm per year colliding with the Eurasian plate that is moving Eastwards. The stress accumulation (in the Longmenshan thrust formation running along the margin of the Sichuan basin) as a result of this motion, caused an earthquake with a focal depth of 19km that resulted in 'large scale structural deformation inside the Asian continent' (CEA, 2008). It is clear that no amount of mitigation can remove the threat that plate movement (a natural factor) imparts on seismic activity, and it will therefore always be present in seismic case studies.

Severe ground shaking was the greatest cause of death and all immediate damage to schools, housing, power lines, hospitals and infrastructure. Over 5 million buildings collapsed and a further 21 million were estimated to have been damaged. However, it is the education system that took the hardest hit; a total of 7,000 classrooms were destroyed killing 10,000 students. Whilst this would always be a devastating number, in context it is much worse; the 2008 earthquake came after China's one child policy and therefore the earthquake wiped out a much larger relative percentage of the regions future workers. Thousands of families were left devastated, with secondary school parents having little hope of further children due to their age. This brings an element of human cause to the disaster: if the national policy had not been in place, or had been relaxed at an earlier date, then the loss of such numbers of students would have been less significant.

Landslides were also a great cause of structural damage and loss of life. Two landslides hit Beichuan, causing considerable damage to already underdeveloped services and infrastructure. Due to the nature of the basin and the dendritic structure of drainage, debris flows will continue to be an issue for up to 40 years after the event; large amounts of rubble found its way into the river system following the landslides. The earthquake was felt up to 1,700km away in Shanghai and therefore gave scope for a large amount of mass movement due to the extent of the coverage of the seismic waves. The earthquake also came before the arrival of the rains, resulting in drier than usual land, requiring less energy to become dislodged. Whilst landslides initially appear to be a physical impact caused by natural processes, the lack of mitigation of such an event is clear. Three schools were built at the base of steep slopes that were already being monitored for mass movement; clearly an example of human negligence that inevitably added to this earthquake becoming a 'disaster'.

There is also strong evidence of further negligence and corruption deeply rooted in building practices. Since 1976, China has operated stringent building code based on a seismic intensity scale (1-12); Sichuan was considered a level 7 on this scale: high enough to make the code mandatory for all new buildings. The code involves the addition of steel to structures to increase their ductility, allowing buildings to 'sway' with ground movement. However, any devastation to modern structures (post 1976), stands as testament to the idea that these regulations were not adhered to in an appropriate manner, nor were they enforced by officials. To save money, builders often used inferior concrete and inadequate construction materials, ultimately leading to the devastation of many buildings that would have otherwise survived, including many schools. This negligence is proven by the lower levels of structural damage suffered from other earthquakes concerning populations of equally high exposure such as Kobe (1995), where building regulations were adhered to allowing an increased number of structures to survive the shaking. It is the amplified vulnerability of the Sichuan people that ultimately caused the increased devastation. Chinese officials blamed the magnitude for the devastation, yet there is great evidence to suggest that a lack of mitigation ultimately led to increased levels of destruction and loss of life, supporting the argument that the Sichuan disaster was of human blame. Man-made structures, such as the building of the reservoir, are likely to have put pressure on the fault. Ultimately, there is strong evidence to suggest that human interference and lack of appropriate building measures combined to amplify the risk of slippage.

Common in many studies involving China, is the secrecy and desire to solve issues internally. This greatly contributed to the devastating impacts of the 2008 earthquake. Secret nuclear testing has long been present in Sichuan province and continues to this day. Whilst there is a possibility that this may have been a trigger for the energy release, the lack of seismic instruments due to the desire to keep interference at a minimum, is certain to have lowered the capacity to predict and determine magnitudes. Improved data means better provision of appropriate hazard perception. Japan is one of the most actively monitored seismic zones in the world, with over 200 seismographs and 4,200 seismic intensity meters. Information collected during a seismic event is able to be instantaneously provided to disaster prevention authorities, rapidly reaching the public through local channels. This data is vital as a trigger for the initiation of relief operations, allowing targeted aid. Chinese models were incorrect and resulted in aid being sent to inappropriate destinations; if a system such as the Japanese example had been implemented in Sichuan, I believe the death toll would have been significantly lower. The technology is available and China is developed enough to utilise it effectively; the fact that they didn't, despite knowing the full risk of the seismic hazard, demonstrates negligence. Although, it is key to mention the differing social attitudes that China holds; it has always been a powerhouse for alternative values. However, I still feel the hazard salience of this threat was not comprehended effectively; as a result, needless lives were lost. Although it is true that Sichuan province is tectonically unstable, it is also clear that dense populations contained within this steep sided valley, as well as a distinct lack of mitigation, were instrumental in the event becoming a 'disaster'. Seismic activity in this region is a constant of habitation there; for the foreseeable future this will not change. However, an increased awareness to seismic risk and a stronger hazard perception, would prove to result in lower scale devastation and faster regeneration after future events. The Sichuan earthquake killed nearly 90,000 people and cost over $150 billion; these losses could have been greatly reduced had a realistic sense of the danger that seismicity presents been utilised effectively. Whilst there is no doubt that the Sichuan earthquake was a natural event, in order to make it a 'disaster', humans inevitably had to contribute. I believe that human negligence and a lack of awareness greatly increased the scale of this earthquake.