The Wenchuan Earthquake and Yaan Earthquake - Research Paper Example

The Strong Earthquake Happened in Sichuan Province, How it Influenced Local People An Earthquake is an impact of the energy release in the Earth crust in an abrupt manner. The impact leads to the creation of seismic waves that cause the shaking of the earth crust. These affects the geological structure of the area. Sichuan Province has experienced a number of earthquakes in the last three centuries. Geologically, it has been shown that the province has had eleven earthquake of magnitude above seven. There has been also eight earthquakes with magnitude range of 6 to 6.9. The most current earthquakes in Sichuan Province are the Wenchuan earthquake and Ya’an earthquake. The Wenchuan and Ya’an earthquakes have been devastating to the local people. Wenchuan earthquake occurred in 2008 while Ya’an earthquake occurred in 2013 (Chen et al 2013). This paper seeks to discuss the occurrence of the Sichuan Province’s earthquake and how influenced local people. The geological structure of Sichuan province. Sichuan Province has a pre-cambrium basement with a double layer texture (Yueqiao et al 2013). This is exposed in the province forming the Western region. This pre-cambrium basement is what forms the Upper Yangtze Platform. In the time of late Palaeozoic-Masozoic geology states that the Sichad seat was the point where the Asian plates extended from. It led to Palaeo-Tethys extended from Southwest Asia to Southeast Asia. Sichuan Province harbors plateaus on its Western side. This plateaus are cited as the greatest Indosinian fold zones on the planet Earth. The province has also experienced very strong Post- Triassic intercontinental modifications. This includes cases of various geotectonic movements in the Province like block faulting, seismic activity, glaciations and mudflows. This incidence has led to a situation referred to as a geological mystery in Sichuan province (Gioncu & Federico 2011). Fig. 2 A map showing Sichuan Province, Source: Google maps. Why there are many earthquakes happened in Sichuan province. Sichuan Province is susceptible to earthquakes and studies have shown reasons for the occurrences of earthquakes in the region (der Hilst 2008). The man-made activities together with the natural factors have led to the high prevalence of earthquakes in Sichuan Province. Engineers in Geology and Seismology have reported that that the water collected in the Zipingpu water reservoir triggered the earthquake. The dam is made up of 470 fit high concrete upstream from Dujiangyan (der Hilst 2008). It was seen that the Sichuan earthquake in May 2008 its epicenter was close to the dam. It was four miles from the dam and the area around the dam was highly affected by the earthquake (Macdougall 2011). CURRENT MASSIVE EARTHQUAKES Wenchuan Earthquake According to the world Commission on dams, the 2008 Wenchuan earthquake was caused by Reservoir- Induced- Seismicity process (R.I.S) (Macdougall 2011). This was due to the pressure that was created by the water in Zipingpu dam. This pressure was exerted within the micro-cracks and fissures in the ground near and under the water reservoir. The increase of water pressure in the cracks lubricated the Longmenshan faults that were already under tectonic stress. Lubrication then caused these faults to slip leading to the release of tectonic energy stored in it. The weight of the water coupled by the water penetration between the faults into the rocks unleashed a chain of ruptures to cause an earthquake (Xu 2009). The impact of construction and filling Zipingpu dam 2004 on Minjiang River was believed to have led to the disaster in 2008. Although the earthquake was unusual in the area, dam construction catapulted the occurrence of an earthquake in the area (Lin & Zhikun 2009). Fig. 2.A map showing Wenchuan 2008 earthquake, Source; Google maps Ya’an Earthquake: According to Caltech Tectonics Observatory Scientists, it is argued that the devastating events of numerous earthquakes in Sichuan Province is because of tectonic plate movements. First of all, the Wenchuan May 2008 earthquake happened in a region that is deformed because two tectonic plates that are colliding. These are the Indian plate and the Eurasian plates; their collision were on a fee approximately 50 million years ago (Chen et al 2013). This led to the area between the two plates to be subjected to strain and deformation. India started to move to the Northern direction at the rate of almost 4cm/year and was pushed towards the Central part of Asia. On the other side, the Tibet was pushing eastward and it was displaced out of its position. Science, therefore, states that the 2008 Wenchuan earthquake occurred when the Eastern section of Tibet was moved eastwards further (Chen et al 2011). The effects of aftershocks following the initial rupture have led to earthquakes in Sichuan Province. It is noted that the aftershocks concentrate along the very rupture fault though their frequency decreases with time. It led to seismic shaking of the mountain range and the basin, where the heavy sedimentation in the basin increased the shaking to cause an earthquake. This is due to movement of the seismic waves resulting from the subsequent aftershocks or from original earthquakes across the basin (Chen et al 2011). These continuous aftershocks and sedimentation in the basin lead to imbalance in the Earth crust causing crust like the Longmenshan crust for this matter. The faults then slip triggering sudden rupture in the earth crust (Tankut 2009). The relationship between two earthquakes Sichuan Province has recorded the current earthquakes that have been very destructive. These are the Wenchuan earthquake that occurred in May 2014 and the Ya’an earthquake. The Wenchuan earthquake was also called the Great Sichuan Earthquake. It occurred at 02:28:01 PM as per the Chinese Standard Time, on Monday May 12 in the year 2008. The earthquake’s epicenter was Wenchuan County and it measured 80 kilometers, and it was located on the North Western part of Chengdu. The Wenchuan earthquake was very massive and its impact was felt in other counties bordering Wenchuan like Shangai and Beijing. The Wenchuan earthquake measured 8.0Ms and 7.9Mw and it was felt to vast distances around the epicenter, as far AS 1700KM. The strong aftershocks from the original earthquake were as high as magnitude 6 and the aftershocks continued hitting the region. This increased the number of casualties and damage caused by the main earthquake (Lin & Zhikun 2010). How local people influenced by earthquakes Statistics estimates that the Wenchuan earthquake led to the death of 69,197 people. Of the total death cases, 98% were from Sichuan Province. It left 374, 176 people injured and 18, 222 were reportedly lost (Wang 2013). The earthquake led to 4.8 million people homeless. The 2008 earthquake was the most dangerous earthquake to occur in China and many people were affected. The affected people from the quake directly or indirectly were As many as 15 million people. Thousands of people were trapped under debris and rubble a situation which made it hard for the rescuing process. Its destructive effects superseded the Tangshan earthquake of 1976 and Chayu earthquake that occurred in 1950 (Chen 2011). Wenchuan earthquake led to damage to millions of property and facilities. It led to the destruction of many buildings and also flattened towns and villages (Shan & Stephen 2012). Wenchuan earthquake destroyed many office buildings, for example, the Jin Mao Tower in Shanghai. In the rural area networking were damaged. Rural infrastructure like roads, the train lines and bridges was destroyed. This destroyed the movement of rescuers making the impact to people very devastating because the earthquake had damaged the networks. The earthquake occurred due to the thrust of the Northeastern to the Southeastern of the Longmenshan fault line. The fault line happened to move the earth crust into two different sections. The more destruction from the earthquake at the epicenter is because of the shallowness of the quake. The aftershocks of the Wenchuan earth quake led to the emergence of disasters which led to more destruction of property and loss of lives. The secondary natural disasters like landslides, mudflows and debris floods. This requires better management techniques in the affected areas so that the effects of the secondary disasters are minimized. It threatens the lives of the residents who opt for migration to other safer places. The earthquake led to instability of the soil particle at slope and also the waters from the water bodies saturated the soil. This led to the occurrences of secondary disasters like the landslides and mudflows. Ya’an earthquake took place on April 20, in the year 201 at 08:02 (according to the Beijing time). Lushan County was its epicenter and the effects of the Wenchuan earthquake was approximately 116Kilimetres from Chengdu. Like the Wenchuan earthquake, it also occurred on the Longmenshan Fault. According to the China Earthquake Data Centre, Ya’an earthquake was placed at Ms 7.0 It had 1,815 aftershocks together with various secondary disasters. These disasters included the landslide, mudflows and earth flows. These secondary hazards were mainly felt to the area nearing the epicenter, around Lushan County (Chen 2011). The epicenter of Ya’an earthquake was seen to be in Miaopingshang which is in the town of Shuangshi. According to the China Earthquake Network Centre it is estimated that the epicenter was approximately 13 in depth and it was about 115 km on the Western side of the Sichuan Provincial capital. Estimates show that the Ya’an earthquake occurred at about 85 km from the Wenchuan’s 2008 earthquake epicenter. This proves it right that the two earthquakes occurred along the Longmenshan fault. The epicenter of the two earthquakes had the same intensity of IX. Another relationship is that the two occurred in Sichuan Province causing effect on the same areas of Chongqinq, Gansu and Yunan (Tankut 2009). The effects of the Ya’an earthquake are loss of lives and facilities was also damaged. It resulted in the death of 196 people (Cheng 2008). There were people who went missing, this was 24. Statistics also shows that 11,826 people were injured and them that were seriously injured reached to 968 people. There was damage to the facilities in the region and property worth of millions was lost. Towns were damaged and majority of the old buildings in Lushan ended up collapsing (Cui 2011). The electricity wire lines were disrupted especially the area around Boaxing, Lushan and Tianguan. The Sichuan highway was disrupted leading to difficulties in rescuing as vehicles were closed on the way to the affected areas. Ya’an earthquake led to the massive damage to the transportation means in the area. The destruction was worsening by the mountainous terrain of Ya’an area (Cheng 2008). The transportation means in the area are water and roads, destruction of bridges and roads led to more death of people as the rescuers were unable to reach the affected areas. Statistics shows that the earthquake destroyed approximately 3,689 km of rural and county roads while 432 km of roads that serve nationally in China were destroyed. There was also the damage to 59 docks and 86 bus stations. These led to severe dame on the transportation facilities in the entire Sichuan Province (Peng 2009). Like Wenchuan earthquake, Scientists have shown that the failure occurred yaan earthquake of the segment that is found on the southern part of Longmenshan. The strike of Longmenshan fault led to the rising of the mountains found in the low lying areas of Sichuan basin. This caused stress on the crust because of the Tibetan plateau than building that led to fracturing in the crust’s stuck rocks (Amaratunga & Richard 2011). These geological processes are believed to be the reasons as to why the area is prone to earthquakes. Studies show that Sichuan frequently experienced seismic activities of more than 13 earthquakes having magnitude 6 or above. Ya’an earthquake not only affected the local and national infrastructure but it also affected regional infrastructure (Xing & Xiwei 2011). On total 224 power lines and 24 electricity substations were damaged by the quake. There were paralysis of electric grids like in the Lushan, Boaxing and Tianquan. (Xing & Xiwei 2011). It has been indicated that, after Wenchuan magnitude, 8 earthquakes in 2008 stress between the two plates were released. This meant that there is no more tremendous shock in the area for 100 years (Pei 2010). The occurrence of Ya’an earthquake is due to human activities that led to geologists to be proved wrong. The construction of Zipingpu dam along Miaozingping led to the lubrication of the Longmenshan faults. (Macdougall 2011). This triggered rocks movement along the fault lines causing another earthquake five years along the line from the 2008 Wenchuan quake (Macdougall 2011). Why Ya’an earthquake has less negative effects than Wenchuan earthquake: It has been founded that the negative impacts of Ya’an earthquake are less when compared with those of Wenchian’s. This is because the Chinese government had learned some lessons in the importance of considering the nature on every developmental activity. The Chinese President Xi Jinping and Premier Li Keqiang had ordered the installation of emergency facilities in the area. There was collaboration of different institutions and departments of the Chinese government to work together in case of an emergency. The rescue team that included personnel from fire brigade, Liberation army, armed police and militia were by 2013 well trained on emergency issues using the current technology (Yang 2010). At the occurrence of Ya’an quake, there was good communication through the media on time and giving a full report. The China Earthquake Administration in like 10 minutes had liaised with the Xinhua News Agency on the broadcasting of the earthquake news. The public was advised on using strong building materials as the destruction and death from weak structures was on the rise in 2008 Wenchuan earthquake. The housing and building department of China stressed on the use of hard materials in building like the use of steel and cement instead of timber and mud (Gioncu & Federico 2011). The government ensured this by giving subsidizing on the building and construction materials so that people can afford this buildings and housing adaptation. By 2013 permanent structures with hard materials had been established in Sichuan Province. Conclusion Earthquakes have negative effects to the social, economical and ecological setup of a country. The country should, therefore, understand its geology so that it put in place measures to adapt or prevent the effects that emanate from earthquakes. Sichuan has had many earthquakes and aftershocks together with secondary hazards like mudflow. The government of China should, therefore, put in place strategies to reduce the negative effects from earthquakes to people and to the property. From the context above it has been founded that human activities like dam constriction can trigger the occurrence of an earthquake. The laws governing the development should, therefore, stick to sustainable development and the carrying out of Environmental Impact Assessments. References Amaratunga, Dilanthi, and Richard Haigh. Post-disaster reconstruction of the built environment rebuilding for resilience. Chichester, West Sussex, U.K. (Ames, Iowa: Wiley-Blackwell, 2011). Chen, LiChun, YongKang Ran, Hu Wang, YanBao Li, and XinQuan Ma. The lushan M S7. 0 earthquake and activity of the southern segment of the longmenshan fault zone. Chinese Science Bulletin 58 (2013): 3475-82. Cheng, Genwei, Xiaodan Wang, Xiubin He, Jihui Fan, and Jianrong Fan. 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