Introduction
May 12th of 2008 found Sichuan province in a state of utter distaster following a collision of tectonic plates. The collision between the Indo-Australian plate and the Eurasian plate caused a thrust fault along the North-West margin of the Sichuan basin; the sudden movement caused intense earth tremors that spread across the province.Tectonic Environment
Sichuan is a tectonically unstable area, having suffered from 11 earthquakes with a magnitude of 7 or more since 1786. Despite the magnitude of the 2008 earthquake being 7.9, the resulting devastation was exeptionally disastrous. This was due to the vulnerability of the dense populus living within the province; it was deemed unlikely even for a 7.9M quake would cause so much destruction.
In Sichuan the convergance between the Tibet Plateau and the Sichuan Basin is localised, and causes stresses in the crust. This stress built up and caused a sudden movement along the fault line, which lead to the tremors.
In Sichuan the convergance between the Tibet Plateau and the Sichuan Basin is localised, and causes stresses in the crust. This stress built up and caused a sudden movement along the fault line, which lead to the tremors.
Below shows a map of China, and highlighted the area of Sichuan province.
The diagram below shows the plate tectonics that caused the earthquake. The movement of the eastern Tibetan Plateau (also called the 'roof of the world') against the Sichuan Basin.
Impacts of the earthquake
The focus of the earthquake was only 19km below groundlevel, resulting in intense earth tremors which caused major devastation. 5.4 million buildings collapsed and 21 million were damaged, which was the direct cause of most of the 90,000 deaths and 375,000 injured.As a result of this 5 million people were left homeless.
Not only were the residential areas ruined, but also school buildings, 7000 classrooms were destroyed, and killed 10,000 students - a massive amount of damage and loss of life.
Most buildings were reduced to rubble, walls collapsing, floors crumbling. Bodies were lying in the streets.
The tremors triggerd mass movement of the slope, and the consequenting landslides killed at least 700 at Qingchuan, and the town of Beichuan was mostly buried by the amoubt of debris that hailed down the mountain. The landslides also blocked river valleys, creating 34 temporary barrier lakes; the rising water levels almost breached the temporary earth dam. 250,000 were evacuated from downstream to higher ground in case of further flooding. They remained evacuated till an artificial channel was completed on 7th June.
The overall cost was $US 150 billion. Over 90,000 people died.
What or who was to blame?
Sichuan has a high exposure to natural hazards and especially seismic activity, due to the rift. As 15 million people live near to the epicentre, including 4 million in the regional capital Chengdu. The high population in such a dangerous and vulnerable area means that more people are likely to be affected by the earthquakes.
However other parts of the world such as southern California have the same high exposure, yet the Sichuan earthquake was still so much more devastating. This seems to be due to how vulnerable the people in the presinct are; about preparation and human response to hazards.
One big vulnerability of Sichuan seems to be the poor infrastructure of the buildings, bad design and construction. The Sichuan province comes under a high priority for mandatory building instructions; to add steel to strengthen buildings and allow them to sway with the shaking ground. These are necessary in high risk areas because without them the buildings will easily snap and collapse.
Unfortunately, many buildings in Sichuan were built before the mandatory code was introduced, so they were mostly low-rise masonry constructions which all collapsed, killing their inhabitants during the tremors. Some of those that were constructed with the code laws still collapsed. This suggests that the compulsory code for building were violated on a wide spread level; either poor concrete and steel reinforcement or the use of inadequate materials. The violations were most probably caused by builders trying to cut costs, so they did not use the required amount of steel in the structures.
Locals blamed the disaster on the corruption of the building work and the lack of enforcement of building regulations; these accusations led to several protests and campaigns. So the government made many of them promises of compensation.
The priority of reconstruction is going to building 4 million new homes for those who became homeless and those whose homes were destroyed. They intended for these homes to be built with the correct safety measures and correct building materials. 3 million homeless rural families will get new homes, and 860,000 city partments will also be built.
The reconstruction plan also includes 169 new hospitals and nearlt 2400 new primary schools - in Suichuan, Gansu and Shaanxi provinces, as they were also affected by the earthquake. Welfare programmes will be put into place in hope to assist the 1.4 million people who've been affected by the poverty following the disaster.
Their ultimate aim is to make the society in Sichuan to be as earthquake-proof as possible, so they are less vulnerable in the future.
However other parts of the world such as southern California have the same high exposure, yet the Sichuan earthquake was still so much more devastating. This seems to be due to how vulnerable the people in the presinct are; about preparation and human response to hazards.
One big vulnerability of Sichuan seems to be the poor infrastructure of the buildings, bad design and construction. The Sichuan province comes under a high priority for mandatory building instructions; to add steel to strengthen buildings and allow them to sway with the shaking ground. These are necessary in high risk areas because without them the buildings will easily snap and collapse.
Who blamed who?
The Chinese officials blamed the volume of destruction on the magnitude of the earthquake.Locals blamed the disaster on the corruption of the building work and the lack of enforcement of building regulations; these accusations led to several protests and campaigns. So the government made many of them promises of compensation.
Response to the Earthquake
The response from the Chinese government was very quick, and they immediately put $US 1.3 billion into strengthening the 2600 schools that were still standing. Unfortunately they went a lot over budget, and ended up spending $US 150 billion.The priority of reconstruction is going to building 4 million new homes for those who became homeless and those whose homes were destroyed. They intended for these homes to be built with the correct safety measures and correct building materials. 3 million homeless rural families will get new homes, and 860,000 city partments will also be built.
Their ultimate aim is to make the society in Sichuan to be as earthquake-proof as possible, so they are less vulnerable in the future.
