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The author:(作者)aaapublished in(发表于) 2013/12/18 9:50:44 Experts say does not exclude Hubei badong 5.1 magnitude earthquake caused by multiple factors
Xinhua, Wuhan, December 17, Reuters new media ("Site," journalist Liang Jianqiang Huang y Li Jinfeng) earthquake of Ms 5.1 in badong County of Enshi Tujia and Miao autonomous prefecture, Hubei Province has passed for nearly 30 hours. Xinhua learned from the earthquake relief headquarters in badong County, ended 17th, cumulative 27,286 people were affected, earthquake caused 3 injuries, no deaths.
Padang earthquake relief, public places, hidden danger eliminating and other progress made in the relief, attracted many Netizen from care. Source close to the three Gorges Dam due to the earthquake, the earthquake is associated with the three Gorges Dam? An earthquake will cause some secondary disaster? Whether the three Gorges reservoir area into the geologically active period? A series of questions has become a network focused.
Padang earthquake and the three Gorges dam to do?
"Friends question" "outside the fat-yin": earthquakes are too rare in Hubei Province, and the three Gorges dam to do? "Trying to do their own Superman": ask Padang earthquake of magnitude 5.1 related to the three gorges? Both are in close proximity.
"Experts online" earthquake expert, Director of the Chinese Academy of Sciences State Key Laboratory of Geodesy and Geodynamics Ni Sidao told reporters that after the earthquake, they in Hubei, Shaanxi, Sichuan, Chongqing, Hunan and other seismic stations detect the earthquake-related data. According to the analysis, the earthquake focal depth of 4 to 7 km, on average for about 5 km, compared to the Mainland average depth of 10 km, this is shallow earthquakes, so damage compared with the 5.1 magnitude earthquake is more serious.
Participate in the Hubei provincial Seismological Bureau of earthquake emergency command researcher Dr Wang Qiuliang said the earthquake's epicentre was located in the three Gorges reservoir area, with the three Gorges Dam, located about 66 km. It causes an earthquake is complex. Because of local geological conditions are complicated, limestone areas more widely distributed, karst is strong, there are some mines, plus the districts of this region is a geological disaster, as a result, the specific causes of earthquakes is more complex, have not ruled out because of a variety of factors.
Wang Qiuliang said, in fact, before the three Gorges reservoir area has 5 magnitude earthquake took place. For example, 1979 Zigui 5.1 earthquake took place. The epicenter of the earthquake, and the Padang earthquake's epicentre was about 10 kilometres away. The earthquake, and in recent years, the three Gorges reservoir area above magnitude 5 earthquake occurred for the first time.
Bring secondary disasters earthquake-prone?
"Friends and" friends "XF" said Padang earthquake, and aftershocks, and it is said that there is an earthquake, what night?
"Experts online" Wang Qiuliang said 5.1 magnitude earthquake, badong County aftershocks woes. As of 17th, 71 aftershocks have occurred, of which 1 level aftershock 23 times (including 2 aftershocks above 2).
According to the Hubei provincial Seismological Bureau monitored most aftershock tremors, mainly located in the karst area, or coal mine areas. On the whole, aftershocks of magnitude decreases, the frequency gradually slowed down. Expected in recent days, may have tremors also occur. In recent years, did not rule out there will be tremors also occur.
Deputy Director of Hubei provincial land and resources Department of geological environment said Zhang Yunqin, secondary disaster is when vibration occurs, under conditions of relative stability, cracking or slipping some monomers. So far, the monitoring data show an earthquake landslide occurred within 10 points, did not induce secondary disasters.
Is located in the reservoir area is focused on the loess slope landslide. Earthquake prevention in the three gorges project, has taken on the loess slope with retaining wall and slope protection-oriented governance. Zhang Yunqin, from monitor stand, without major distortion by the quake on the loess slope, but not let down our guard, where there have been separate crew long-term monitoring.
Entering the three Gorges reservoir area and geologically active period?
"Friends ask" friend "sunshine man" said that Hubei has entered the geologically active is the Padang earthquake predicting signal?
"Experts online" historically prone to geological disasters in three Gorges area, documenting large-scale landslides more than more than more than 10. According to Wang Qiuliang on the Quake and aftershocks, does not mean that entered a period of high incidence of geological disasters in the three Gorges area. In 2003, the three Gorges reservoir before impoundment, area there was geological disasters in the reservoir area. As dedicated network construction for geological hazard monitoring capacity was further strengthened.
For three Gorges reservoir induced geologically active speculation, China three gorges Corporation Chairman Cao Guangjing was in an interview with Xinhua, explained that reservoir will induce or, more accurately, it is important to refer to trigger earthquakes, but quakes exceeding levels of tectonic earthquakes in the area, has built a large reservoir in the world hundreds of thousands of, research on induced many conclusions are consistent. Frequency of induced earthquake in the initial impoundment will be more, but as time goes on, will have reduced or even disappear.
Monitoring data show that during the water storage reservoir-induced earthquake activity is dominated by micro-seismic and seismic, mainly raised by Karst, caves soak. Current academic recognition, the stereotype of reservoir-induced earthquake, the reservoir may trigger a near distance area and is close to the limit of seismogenic fault. According to hydrogeological conditions, kushui distance does not exceed the Bank's first watershed to the outside, usually about 3 per cent from the Bank, up to no more than 10-kilometer.
China National water resources and hydropower Research Institute Professor-level senior engineer Chen Houqun, academician of CAs, reservoir's normal water running, there is a longer time of reservoir Bank reconstruction process. In view of the covert geological disasters and emergencies, high and steep slope unstable rock collapse on both sides making it difficult to find forecasts, area at the same time excessive expansion in size and population of the town in recent years, land development and construction of disaster risk should not be overlooked, so the geological disaster prevention still need to attach.
新华网武汉12月17日新媒体专电 (“中国网事”记者梁建强 黄艳 李劲峰)湖北省恩施土家族苗族自治州巴东县5.1级地震已过近30小时。记者从巴东县抗震救灾指挥部获悉，截至17日14时，累计27286人受灾，地震致3人受伤，无人员死亡。
巴东地震救援、群众安置、隐患消除等抗震救灾进展情况，引来众多网民牵挂。由于此次地震震源比较靠近三峡大坝，地震是否与三峡大坝有关？地震是否将带来一些次生灾害？三峡库区是否进入地质运动活跃期？一系列疑问也成为网络关注焦点。
巴东地震与三峡大坝有关吗？
【网友疑问】“天外肥贤”：湖北地震太少见了，和三峡大坝有关吗？“努力做自己的superman”：想问一下巴东5.1级地震跟三峡是否有关系？两者的距离很近。
【专家答疑】地震专家、中科院大地测量与地球动力学国家重点实验室主任倪四道告诉记者，地震发生后，他们在湖北、陕西、四川、重庆、湖南等多地的地震台站都测到此次地震的相关数据。根据分析，这次地震震源深度为4到7公里，平均起来为5公里左右，相较于大陆地震平均10公里的深度，这次算浅源地震，因此破坏程度较一般5.1级地震更为严重一些。
参与此次地震应急指挥的湖北省地震局副研究员王秋良博士表示，此次地震的震中位于三峡库区，与三峡大坝相距约66公里。这一次地震的成因比较复杂。因为当地的地质条件比较复杂，灰岩区分布比较广，岩溶发育比较强，也有一些煤矿，再加上这一区域本来就是地质灾害高发区，因而，地震的具体成因比较复杂，不排除是多种因素综合的缘故。
王秋良说，其实，三峡水库蓄水之前库区也曾发生过5级以上的地震。比如，1979年秭归发生过5.1级地震。那次地震的震中，与此次巴东地震的震中相距仅10公里。这次地震，也是近年来三峡库区第一次发生5级以上地震。
地震是否将带来次生灾害多发？
【网友提问】网友“xf”说：巴东地震，结果余震不断，据说还有一次地震，夜晚怎么办？
【专家答疑】王秋良说，5.1级地震发生后，巴东县余震接连出现。截至17日14时，已发生余震71次，其中1.0级以上余震23次(含2.0级以上余震2次)。
据湖北省地震局监测，多数余震为微震，主要分布在岩溶发育区或者煤矿分布区。从整体上看，余震的震级逐渐减小、频次逐渐减缓。预计最近几天中，还可能有微震出现。近几年内，也不排除会有微震出现。
湖北省国土资源厅地质环境处副处长张云钦表示，次生灾害主要是指震动发生后，相对稳定的情况下，一些单体开裂或者滑动。截至目前，监测数据显示地震范围内出现10个滑坡点，没有诱发次生灾害。
位于库区的黄土坡是重点滑坡防治点。三峡库区地震防治工程，对黄土坡采取了以挡墙和护坡为主的治理。张云钦表示，从目前监测看，黄土坡在此次地震中没有出现重大变形，不过不能放松警惕，此处一直有专班人员长期监测。
三峡库区是否进入地质运动活跃期？
【网友提问】网友“阳光男人”说，巴东地震是否预示湖北已经进入地质运动活跃期信号？
【专家答疑】三峡地区历史上就是地质灾害多发区，记载的大型崩塌滑坡就有10余处之多。据王秋良介绍，这次地震及余震，并不意味着三峡库区地质灾害进入高发期。在2003年三峡水库蓄水之前，库区一带也曾有地质灾害发生。随着相关专用台网的建设，针对地质灾害的监测能力进一步加强。
针对三峡库区蓄水诱发地质运动活跃的猜测，中国长江三峡集团公司董事长曹广晶曾在接受记者采访时解释，水库蓄水会诱发或更准确一点应该叫触发地震，但地震的震级不会超过该地区构造地震的水平，世界上已经建成的大型水库几十万座，关于诱发的研究成果很多，结论都是一致的。诱发地震的频度在蓄水初期会多一些，但是随着时间的推移，会逐渐减少，甚至消失。
监测数据表明，蓄水期间水库地震活动以微震和极微震为主，主要由岩溶、矿洞浸水引发。目前学术界公认，对构造型水库诱发地震来说，水库蓄水只可能触发距离库区较近且已接近极限状态的发震断层。根据水文地质条件，库水向外渗透距离不会超过库岸第一分水岭，一般距库岸边约3到5千米，至多不大于10千米。
中国水利水电科学研究院教授级高工陈厚群院士表示，水库正常蓄水运行后，仍有一个较长时间库岸再造过程。鉴于地质灾害具有隐蔽性和突发性，两岸高陡岸坡危岩崩塌险情难以发现预测，同时库区近年来城镇规模和人口过度扩展，土地开发建设致灾危险性不容忽视，因此对地质灾害防治仍需高度重视。
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