The EO has interviewed three experts in the field of disaster reduction via emails on the earthquake that hit Sichuan, China, recently. Below is the full text of their responses:
Sálvano Briceno, Director
International Strategy for Disaster Reduction
UN/ISDR, Geneva, Switzerland
EO: What is your view on the Chinese government’s performance in handling the disaster?
Briceno: China has for a long time established an efficient disaster response system to cope with disasters that explains part of its performance in managing this new tragedy. The four level of its disaster contingency plan which attributes specific tasks and responsibilities to central and local authorities have allowed a quick and effective response and helped a great deal to save lives. I was impressed by the rapidity of the emergency response and the way citizens were quickly mobilized and ready to participate in the rescue effort. Many people were saved thanks to this collective effort.
The magnitude of the earthquake which was closer to 9 created a terrible pressure on buildings and infrastructure that would have caused enormous damage in any other country. We know that the constructions of resistant buildings are an important measure to reduce the number of death and injuries when earthquakes happen and I know that China is obviously concerned about the building losses. China achieved a lot in the past ten years in terms of development and I know that disaster risk reduction policies are part of its government priorities. China has an active National committee for disaster reduction which is already working on these issues and I am confident that they will know how to face this new challenge.
EO: Do you have some suggestions for the Chinese government in the up coming rebuilding process?
Briceno: The rebuilding phase is obviously a very important phase to build back better and I know that the Chinese government has already taken some measures to assess the losses and analyze the extent of the damage caused by the earthquake to rebuild in a more resilient way. Chinese people are very good in learning from past experiences and sharing technical knowledge with other experts and I have no doubt that China disaster managers will draw the necessary conclusions and will rebuild in a more resilient way.
Badaoui Rouhban, Chief
Section for Disaster Reduction
UNESCO, Paris, France
EO: Do we have the ability to predict 8-magnitude earthquakes before it happened?
Rouhban: It is not possible to predict the day and location of an earthquake, including an 8- magnitude one. However it is possible through in-depth seismological research, measurements and observations to estimate the probabilities for the occurrence of potential future earthquakes in a given geographical location. For example, scientists are able to estimate that over the next 20 or 30 years the probability of the occurrence of a major earthquake in Istanbul, Tokyo, Tehran, Chile or the San Francisco Bay area is such and such....(in percentage). The Chinese have successfully and exceptionally been able to predict the Haicheng earthquake in north-east China in 1975, which remains the only destructive earthquake to have been successfully predicted. This enabled several hours' warning to be given and the loss of life to be kept very low.
EO: According to your experiences, how do you explain the collapse of so many buildings in China?
Rouhban: Combination of the following parameters: the high magnitude of the earthquake (7,9 magnitude); the small depth of the earthquake focus (less than 10 Kms beneath the surface) which makes the earthquake a "shallow" earthquake and thus the seismic waves reach the surface and the buildings more quickly and strongly; the inappropriate resistance of some buildings and their foundations and the unfavorable conditions of soil.
EO: Is it possible to resist an 8-magnitude earthquake?
Rouhban: Yes, provided we make a proper design and construction of the building. The cost of the construction of the building will consequently be higher.
EO: Nearly a week has passed, yet aftershocks are still happening in Wenchuan and around. Some people said it seemed as though the epicenter was moving towards the north. In your experiences, is that possible? Is it possible to have another earthquake of the same magnitude to hit China in near future?
Rouhban: The occurrence of the aftershocks is not abnormal. Current data do not confirm the existence of other foci compared to the one of the initial earthquake. We have to wait for the results of the seismological analysis. It is too early to have a full understanding of the mechanism of the main shock and the aftershocks. There are no indications that what happened is to be linked to what might possibly happen in the future in China. Again, we cannot predict a future earthquake. Earthquakes of such a magnitude have happened in China and elsewhere in the world in the past years and centuries and can still happen in the future. It is a fact that China, liker many other countries in the world, has seismic areas.
EO: What is your view on the Chinese government’s performance in handling this disaster?
Rouhban: This is a major disaster. There is no country in the world which can cope easily with such a big disaster. The international community sympathizes with China facing this disaster.
EO: Do you have some suggestions for the Chinese government in the up coming rebuilding process?
Rouhban: We need to draw lessons from each natural disaster, from each earthquake. I trust the Chinese authorities concerned will draw the appropriate lessons from this earthquake in order to make the communities, the populations and the buildings safer against future earthquake hazards and other natural hazards. China has first-class and very competent scientists, seismologists and engineers who will be very able to provide policy-makers in China with appropriate scientific and technological information to guide the reconstruction process.
Dr. Carlos Estuardo VENTURA, Director
Earthquake Engineering Research Facility
Department of Civil Engineering
The University of British Columbia
Vancouver, CANADA
EO: Do we have the ability to predict 8-magnitude earthquakes before it happened?
Ventura: The technology that we have today does not allow us to predict earthquakes, in general. There have been cases, however, in which scientific-based predictions have worked for certain types of earthquakes and regions of the world. I am confident that one day in the not so distant future we will know enough about earthquakes that it would be possible for us to make predictions with a high degree of confidence.
EO: According to your expertise, how do you explain the collapse of so many buildings in China?
Ventura: The collapse of a building generally results from the combination of severe ground shaking, poor structural design and improper use of construction materials. A possible cause of the collapse of so many buildings could be explained by the high severity of the shaking of the ground during the earthquake and poor quality of construction materials used. It is clear that the buildings were not designed and built to resist severe earthquakes. Since I have not visited the area affected by the earthquake and I only have seen pictures of the collapsed buildings, it is not possible for me to tell you what are all the reasons for the collapse of so many buildings.
EO: Is it possible to resist an 8-magnitude earthquake?
Ventura: Yes. There is technology available today that uses construction materials in a way that a building would be able to resist the shaking produced by an earthquake of such magnitude. Depending of the technology used, it is possible to control the damage that a building may suffer, and prevent its collapse.
EO: Nearly a week has passed, yet aftershocks are still happening in Wenchuan and around. Some people said it seemed as though the epicenter was moving towards the north. In your experiences, is that possible? Is it possible to have another earthquake of the same magnitude to hit China in near future?
Ventura: Generally, after the main shock, and depending of the type of geological fault that caused the earthquake, the aftershocks may tend to occur in a certain direction with respect to the epicenter of the main shock. It is not that the epicenter of the main shock transfers its location, but that each aftershock has its own epicenter. We know that, in general, the magnitude of the aftershocks tends to be less than the magnitude of the main shock as the time passes. However, there is always a possibility that another nearby fault may become active and generate another earthquake of similar magnitude. The seismologists familiar with the seismic of the region would be able to tell you if the possibility of another earthquake of similar magnitude is likely to occur in the region.
EO: What is your view on the Chinese government’s performance in handling this disaster?
Ventura: My answer is based on what I have seen in the news here in Canada. It seems to me that the government has reacted rapidly and has taken the necessary steps to proceed with the search and rescue operations. It is commendable to see that the government has reacted very fast to help the Chinese people affected by the earthquake.
EO: Do you have some suggestions for the Chinese government in the up coming rebuilding process?
Ventura: The rebuilding process is going to be long and complicated. Rebuilding not only entails construction of new buildings and repair of damaged ones, but also rebuilding the confidence of the Chinese people. It is very important to educate people about the effects of earthquakes and of the steps that each citizen can take to prevent or minimize the effects of future earthquakes. It is inevitable that earthquakes will occur again, and again, but we can take the necessary steps to avoid the devastation and pain that they cause. It is also imperative that the government insures a safe construction of schools, hospitals and other buildings that house emergency response groups. The loss of life of school children and teachers can be prevented, and it is up to the governments of the world to make sure that this does not happen again.
I am very, very sorry for the impact that this earthquake has caused to the people of China. The loss of life and property is tremendous and here in Canada we are very sad about this. We need to take all the necessary steps to prevent this from happening again. I would like to extend my sincere condolences to all the Chinese families that lost beloved ones during the tragic events of last week.
