At a press conference sponsored by the State Council Information Office on Thursday, Li Qianghua, of the China Seismology Bureau spoke of the efforts made to prepare and mitigate for earthquakes in the first half of the year.
I. The situation of earthquake disasters in China since the outlet of 2003
Since the outlet of 2003, 27 earthquakes with magnitude over 5 occurred in China, among which 22 took place in the mainland area, 4 in Taiwan and its adjacent sea waters, and one in South China Sea. Among them, earthquakes with magnitude 6 and above account for 4, which are the Magnitude 6.8 Jiashi-Bachu earthquake in Xinjiang Uygur Autonomous Region on February 24th, the Magnitude 6.6 Delingha earthquake in Qinghai province on April 17th, the Magnitude 6.1 earthquake in the north of Bange County in Tibet Autonomous Region on July 7th, and the Magnitude 6.2 Dayao earthquake in Yunnan province on July 21st separately. 8 Earthquakes with magnitude 5 to 6 took place, among which five occurred in the boundary area between Qinghai Province and Tibet Autonomous Region, one in Balinzuoqi county - Alukeerqinqi county area in Inner Mongolia Autonomous Region, one in Yanyuan county in Sichuan Province, and 11 aftershocks to the main-shock of 6.8 earthquake in the Bachu-Jiashi area in Xinjiang Uygur Autonomous Region.
Eight among the 22 earthquakes with magnitude over 5 in mainland area caused casualties and property losses, resulting in the total fatalities of 291, more than 2200 people seriously wounded, over 4500 people slightly injured, about 1.74 million people affected, and the direct economic losses reached more than three billion RMB. The most destructive one is the magnitude 6.8 Bachu-Jiashi earthquake in Xinjiang Uygur Autonomous Region with 268 deaths, 2058 seriously injured, about 650,000 victims, and the direct economic loss amounted to 1.3 billion RMB. It is the most devastating continental earthquake of China since the Lijiang earthquake of Yunnan Province in 1996.
II. The earthquake preparedness and disaster mitigation in China
Earthquake is a natural disaster which may cause tremendous losses to mankind. With the economic development and acceleration of urbanization, earthquake disaster could result in greater economic losses and bigger social catastrophe. China is an earthquake-prone country with severe seismic disasters. With the land area covering only 7% of the world, 33 percent of the global continental destructive earthquakes occurred in China in 20th century. Nearly 600,000 people were killed by earthquakes in China in the last century, accounting for 50% fatalities caused by earthquake during the same period all over the world. The two earthquakes with death toll over 200,000 in 20th century both occurred in China. One is the Magnitude 8.6 Haiyuan earthquake in Ningxia Hui Autonomous Region in 1920 with the death toll of over 230,000, and another one is the Magnitude 7.8 Tangshan earthquake in 1976 which killed 240,000 lives.
The reason why China has been suffering from earthquake disaster so severely is that China is located between the Pacific plate and the Indian plate, where the crustal tectonic movement is intensive and complex, which makes the seismicity in China characterized by the following features:
a. High frequency, high intensity
In 20th century, there were 8 earthquakes with magnitude 8 and above, 65 between 7 and 8, and 382 between 6 and 7, which accounts for one third of the world continental destructive earthquakes.
b. Wide distribution
According to historical records, destructive earthquakes with magnitude 5 and above occurred in every province (autonomous region and municipality) in China, and 29 provinces (autonomous regions and municipalities) hit by destructive earthquakes with magnitude 6 and above.
c. Severe disaster situation
Due to the above mentioned features of earthquake disaster in China, earthquake hazard is fatal in China. 41 percent territory of mainland area and about 70 percent big cities with population above one million are located in high intensity zone with the seismic intensity of and above VII. In addition, being a developing country, China is still relatively weak for its capability of seismic design for buildings and structures on the whole. Hence, China is a country with severe earthquake disasters.
Chinese government has attached great importance to the efforts of earthquake preparedness and disaster mitigation which concerns people's life and property security. Since founding of the People's Republic, especially in the past ten more years, efforts of earthquake preparedness and disaster mitigation in China have witnessed great achievement and played important role in social and economic development.
· Ability of earthquake monitoring and prediction has steadily improved
Earthquake monitoring and prediction is the fundamental link and top priority for the effort of earthquake preparedness and disaster mitigation, since a successful earthquake prediction may greatly reduce life losses and injuries. At present, over 400 national-level and province-level seismic stations and more than 30 regional telemetric seismic networks have been set up, in addition to about 1400 seismic stations owned by local governments and enterprises, as well as more than 8000 observation points run by volunteers. During the period of ninth "Five-Year-Plan" from 1996 to 2000, observation approaches of the seismic stations had been digitally upgraded, and China Crustal Movement Observation Network, which is based on Global Positioning System (GPS), had been established. Seismic monitoring system of China has shifted from single-station observation to network observation and from analog technique to digital technique, and has been integrated into a national seismic network of multi-discipline and multi-subject of observation. Earthquakes with magnitude 4.0 or above could be effectively monitored nationwide, 1.5 to 2.0 in eastern important provincial capitals and their neighboring areas, and 1.0 to 1.5 in the Capital Circle Area.
Since 1966 Xingtai earthquake, China has strengthened exploration in the practice of earthquake prediction. The successful prediction to 1975 Magnitude 7.3 Haicheng earthquake in Liaoning Province which greatly avoided fatalities is the first one in human history. In recent years, predictions to certain extent have been realized to the destructive earthquakes with magnitude above 5.0, such as 1999 Xiuyan earthquake in Liaoning Province. However, earthquake prediction, especially impending earthquake prediction remains an unsolved scientific issue worldwide, and earthquake prediction is still at a quite low level.
· Resistance to earthquake disaster strengthened
Human life and property losses by earthquake disasters are mainly caused by collapse and damage of buildings; hence aseismic design for the buildings is of key importance. Effort of earthquake disaster prevention mainly pays off in the following aspects. The first one is that fundamental work for aseismic design has been gradually strengthened. Seismologists have compiled seismic intensity map and seismic zoning map, which provides scientific and reasonable standard of aseismic design for common civil buildings, and at the same time carried out seismic micro-zoning, earthquake disaster estimation and active fault detection for cities, which have laid foundation to improve earthquake preparedness and disaster mitigation in cities. The second one is that supervision and inspection to aseismic design of construction projects have been gradually strengthened. The administrative authority has regarded aseismic design as one of the important contents of quality control in the construction projects, especially the key procedures of key projects, such as site survey, design and construction. For instance, earthquake safety assessments had been carried out for the projects of the huge Three Gorges Project, Dayawan Nuclear Power Plant, Gas Transportation from the West to the East, Qinghai-Tibet Railway etc. and the projects could possibly cause severely secondary disasters otherwise. The third one is that reinforcement work to the buildings with weak resistance to earthquakes has been actively carried out in the earthquake monitoring strengthened area, which made resistant ability of the buildings to earthquake obviously increased. The fourth one is that instruction to aseismic design for the farm houses and public facilities in village and town has been strengthened. Technical advisory has been given via publicity and education to push forward the work of aseismic design in village and town.
· Effort of earthquake disaster emergency response has been initiated
According to the data of Tangshan Earthquake, the survival rate was 80 percent if the buried people could be rescued within one day, and 53 percent within 2 days, but only 7 percent could be left in the fifth day. To meet the requirement of in-situ emergency rescue and relief work for the earthquakes home and abroad, the first National Earthquake Disaster Emergency Relief and Rescue Team was established in 2001. The 230-person team consists of military engineering unit, seismologists and medicals, and is equipped with advanced tools for search and rescue, medical treatment, cutting and expanding, and sniffer dogs. The team participated in the relief and rescue work in Bachu-Jiashi earthquake in Xinjiang Uygur Autonomous Region and Algeria earthquake, made contribution to the post-quake relief work in the quake stricken areas.
Working out earthquake emergency preplan is one of the significant approaches for earthquake preparedness and disaster mitigation. It makes it possible to have prompt response to the earthquake emergency and to carry out work in an orderly manner once earthquake occurs so as to avoid the losses resulted from inappropriate command and sluggish response. Governments at various levels and governmental departments concerned have been actively working out and improving earthquake emergency preplans. They have set up the aids warehousing system for disaster relief and rescue. They are in charge of the implementation as well as the supervision of countermeasures for emergency relief and rescue. At present, the national earthquake emergency preplans at different levels and different departments have been formed and played significant roles in the earthquake disaster relief work thereafter.
· Significant progress has been made in legislation of earthquake preparedness and disaster mitigation
Legal system of earthquake preparedness and disaster mitigation is the key to guarantee the function of earthquake preparedness and disaster mitigation of a society. With the promulgation and implementation of the Law of the People's Republic of China on Protecting Against and Mitigating Earthquake Disasters, which has come into force since March 1998, together with the associated ordinances, such as the Ordinance of Earthquake Prediction Management, and the Ordinance of Seismic Safety Evaluation, the work on administration, legal regulation, supervision and checking system has been gradually enhanced. The management on earthquake preparedness and mitigation has stood its track on standardization and legalization.
· The overall awareness of the general public has been improved
Strengthening the publicity of earthquake knowledge to improve the social consciousness is an effective approach for earthquake preparedness and disaster mitigation. Through years efforts on the publicizing the earthquake knowledge, the public's involvement in earthquake preparedness and disaster mitigation has been gradually enhanced. The capabilities of discriminating quake rumors and the skills on how to avoid casualties in a quake and on how to carry out self rescue and mutual rescue have been steadily improved.
On the other hand, we should know clearly that there are still quite a lot of difficulties and problems in earthquake preparedness and disaster mitigation. There is still a relatively big gap between our capability of earthquake monitoring, prediction and the social requirement. The aseismic capability for the structures in some area and buildings is lower than it should have met with; due to the code of aseismic design had not been strictly followed. The emergency rescue capacity is far from the requirement of our quake prone-disaster situation, and a complete set of system of emergency relief and rescue has not been set up. In the meantime, the overall awareness of earthquake knowledge for the whole nation should be upgraded to a higher level.
III. The main approaches for the improvement of the capability of earthquake preparedness and disaster mitigation
The National Conference of Earthquake Preparedness and Disaster Mitigation held by the State Council in 2000 reiterated that the highlights for earthquake preparedness and disaster mitigation in the forthcoming period of time should be focused on the following aspects, i.e. further perfecting the system of earthquake monitoring and prediction, which should mainly rely on the experts combined with those amateurs; establishing the system of quake disaster preparedness which has to strictly abide by the relevant laws or ordinances and should be always on high alert; setting up the prompt responding and effective force of emergency relief and rescue system. Only through the organic combination of all these efforts can we improve the integrated capabilities of earthquake monitoring and prediction, aseismic design for buildings and structures and emergency relief and rescue.
In order to further strengthen the construction of earthquake-related infrastructures and improve the capability of earthquake preparedness and disaster mitigation, during the 10th Five-Year Plan period, the Central and local governments will have a total investment of about 2.7 billion RMB for the construction of the project of "China Digital Earthquake Observation Network". The project will focus on the construction of seismometric network, precursory observation network as well as the network for strong ground motion observation; it will also involve the three technical systems covering the detection for active faults, the information-sharing services and the emergency commanding facilities. The project will be finished by the end of 2007. A digitalized, high precision and prompt responding earthquake observation network with coverage of the whole country will be formed at that time, able to provide fundamentally scientific data for urban planning and construction. Through the implementation of this project, the overall capabilities of earthquake monitoring and prediction, disaster preparedness and mitigation as well as emergency relief and rescue will be greatly improved.
(China.org.cn September 5, 2003)
