Research on inversion of average stress field by genetic algorithms

ＲｅｓｅａｒｃｈｏｎｉｎｖｅｒｓｉｏｎｏｆａｖｅｒａｇｅｓｔｒｅｓｆｉｅｌｄｂｙｇｅｎｅｔｉｃａｌｇｏｒｉｔｈｍｓＸＩＮＧ－ＸＩＮＤＵ（杜兴信）ＨＵＩ－ＬＩＮＧＺＨＡＮＧ（张惠玲）ＸＩＵ－ＬＩＮＧＬＵ（鲁秀玲）ＣＨＵＮ－ＳＨＥＮＧＺＨＡＮＧ（张春生...     

Upper mantle flow beneath the Northwest of China and its lithospheric dynamics

ＵｐｐｅｒｍａｎｔｌｅｆｌｏｗｂｅｎｅａｔｈｔｈｅＮｏｒｔｈｗｅｓｔｏｆＣｈｉｎａａｎｄｉｔｓｌｉｔｈｏｓｐｈｅｒｉｃｄｙｎａｍｉｃｓＪＩＡＮ－ＨＵＡＨＵＡＮＧＩ（黄建华）；ＸＩＡ－ＨＵＡＣＨＡＮＧＩ（常筱华）ａｎｄＲＯＮＧ－ＳＨＡＮＦＵＩ傅容珊）（...     

Ray equation migration of wide-angle reflections in Dabie orogenic zone

ＲａｙｅｑｕａｔｉｏｎｍｉｇｒａｔｉｏｎｏｆｗｉｄｅａｎｇｌｅｒｅｆｌｅｃｔｉｏｎｓｉｎＤａｂｉｅｏｒｏｇｅｎｉｃｚｏｎｅＸＵ－ＹＡＯＺＨＥＮＧ１）（郑需要）ＣＨＵＮ－ＹＯＮＧＷＡＮＧ２）（王椿镛）ＸＩＡＯ－ＬＩＮＧＬＡＩ１）（赖晓玲）ＸＩＡＮ...     

Inversion of breakout data from inclined boreholes for stress state of the upper crust in Jizhong depression

ＩｎｖｅｒｓｉｏｎｏｆｂｒｅａｋｏｕｔｄａｔａｆｒｏｍｉｎｃｌｉｎｅｄｂｏｒｅｈｏｌｅｓｆｏｒｓｔｒｅｓｓｓｔａｔｅｏｆｔｈｅｕｐｐｅｒｃｒｕｓｔｉｎＪｉｚｈｏｎｇ　ｄｅｐｒｅｓｓｉｏｎＹＡＮ－ＸＩＡＮＧＹＵ（俞言祥）ａｎｄＺＨＯＮＧ－ＨＵＡＩＸＵ（...     

StudyofCurieisothermalsurfaceinSichuanBasinandtheseismicareaonitswesternmar┐gin

ＳｔｕｄｙｏｆＣｕｒｉｅｉｓｏｔｈｅｒｍａｌｓｕｒｆａｃｅｉｎＳｉｃｈｕａｎＢａｓｉｎａｎｄｔｈｅｓｅｉｓｍｉｃａｒｅａｏｎｉｔｓｗｅｓｔｅｒｎｍａｒ┐ｇｉｎＸＩＡＮＺＨＡＮＧ（张先），ＸＩ－ＦＥＮＧＨＵ（虎喜凤），ＪＩＮＧ－ＸＩＵＳＨＥＮ（沈京秀...     

Effects of magnitude accuracy and complete－ness data on seismic hazard parameters

Ｅｆｆｅｃｔｓｏｆｍａｇｎｉｔｕｄｅａｃｃｕｒａｃｙａｎｄｃｏｍｐｌｅｔｅ┐ｎｅｓｄａｔａｏｎｓｅｉｓｍｉｃｈａｚａｒｄｐａｒａｍｅｔｅｒｓＨＵＩ－ＣＨＥＮＧＳＨＡＯ（邵辉成），ＪＩＡ－ＳＨＵＸＩＥ（谢家树），ＰＩＮＧＷＡＮＧ（王平）ａｎｄＹＡ－Ｘ...     

Study on simulation of spatial correlative earthquake ground motion field

ＳｔｕｄｙｏｎｓｉｍｕｌａｔｉｏｎｏｆｓｐａｔｉａｌｃｏｒｒｅｌａｔｉｖｅｅａｒｔｈｑｕａｋｅｇｒｏｕｎｄｍｏｔｉｏｎｆｉｅｌｄＸＩＡＯ－ＪＵＮＬＩ（李小军）ＦＥＮＧ－ＸＩＮＺＨＡＯ（赵凤新）ＹＵ－ＸＩＡＮＨＵ（胡聿贤）ＩｎｓｔｉｔｕｔｅｏｆＧｅｏ...     

Study on the characteristics of crust－mantle transition zone in Western Yunnan Province

Ｓｔｕｄｙｏｎｔｈｅｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｃｒｕｓｔ┐ｍａｎｔｌｅｔｒａｎｓｉｔｉｏｎｚｏｎｅｉｎＷｅｓｔｅｒｎＹｕｎｎａｎＰｒｏｖｉｎｃｅＨＯＮＧ－ＸＩＡＮＧＨＵ（胡鸿翔）ＺＨＯＮＧ－ＹＡＮＧＬＩＮ（林中洋）ＹＩＮ－ＪＵＢＩＡＮ（边银...     

The research on Hainan earthquake insurance system

ＴｈｅｒｅｓｅａｒｃｈｏｎＨａｉｎａｎｅａｒｔｈｑｕａｋｅｉｎｓｕｒａｎｃｅｓｙｓｔｅｍＦＡＮ－ＬＵＡＮＳＨＥＮ１）（沈繁銮），ＺＨＩ－ＸＩＯＮＧＬＩ１）（李志雄），ＤＩＮＧＣＨＥＮ１）（陈定），ＨＡＩ－ＨＵＡＬＩ１）（李海华），ＤＩＮＧ－ＪＩＥＷ...     

Researchonpredictionofthefolowingnotice┐ableshocksofearthquakesequences

Ｒｅｓｅａｒｃｈｏｎｐｒｅｄｉｃｔｉｏｎｏｆｔｈｅｆｏｌｏｗｉｎｇｎｏｔｉｃｅ┐ａｂｌｅｓｈｏｃｋｓｏｆｅａｒｔｈｑｕａｋｅｓｅｑｕｅｎｃｅｓＰＵ－ＸＩＯＮＧＬＩＵ（刘蒲雄），ＸＩＵ－ＱＩＣＨＥＮ（陈修启），ＸＩＡＯ－ＪＩＡＮＬＵ（吕晓健）ａｎｄＤ...     

中国大陆近期地震活动性与中长期地震概率预测

通过地震震级概率预测方法得到的中国大陆各地震带１９９０￣２００５年地震危险性预测结果与近几年实际地震活动情况的对比研究。对这一方法及其实际预测效果有了更深入的理解。在此基础上，对中国大陆各地震带１９９６年７月至２００５年发生不同震级的地震概率进行了预测。结果表明，未来中国大陆继续处于１９８８年底以来的新一轮地震活跃阶段，中国东部地震发生概率继续增加，华北地块的北部边缘地震带和右江地震带有可能发生６     

Research on the Probability of Earthquake Occurrence in the Daduhe Drainage Area

This paper applies the Seismic Hazard Analysis method for the cities of China to research on the probability of earthquake occurrence in the Daduhe drainage area, where the cascade dam system is located. This research is based on the potential seismic source scheme of the Seismic Ground Motion Parameter Zonation Map of China （2001）, and uses Poisson distribution as an earthquake occurrence model. Earthquake magnitude obeys truncated exponential distribution. The spatial distribution function of the potential seismic source zone is taken as the first-class spatial probability distribution, and the homogeneous probability distribution in the potential seismic source zone as the second-class spatial probability distribution. Considering the seismic intensity attenuation relationship of western China, we compute the occurrence probability of an earthquake around magnitude 6.0 （5.5 - 6.5）, 7.0 （6.5 - 7.5） and over 7.5 in the Daduhe drainage area, where 22 series cascade dams will be built. The results can be used for hydropower plant planning, hydropower dam site selection and seismic fortification.     

试用累积求和方法研究地震活动平静现象及大震概率预报

以表征区域地震活动强度背景的震级期望值作为单个地震事件的目标值,利用震级累积和C值随时间的变化分析地震活动相对平静现象,并给出其显著性检验. 文中还定量分析了平静异常与大震的关系,提出了利用核函数对大震发生时间进行概率外推的方法. 用上述方法对华北区的山西、张家口-渤海地震带的部分地区及新疆区域进行计算,显示该方法能够描述地震活动平静现象,并可合理地对未来大震发生时间进行概率外推估计.     

地震区划原则和方法的研究——以华北地区为例.

本文基于对我国华北地区地震活动在时间和空间不均匀分布的认识,吸收了近20年来地震预测方面的科研成果,采用目前国际通用的地震危险性概率分析方法,通过对华北区划的试验,对地震区划的原则和方法提出了如下改进: 1.以地震带作为地震活动性参数的统计单元.引入地震活动趋势估计因素,评定表征地震活动水平的年平均发生率,以使区划结果同预测未来时间段地震活动水平相适应; 2.采用按震级挡次分配各潜在震源区的年平均发生率,可以合理地评估高震级地震的危险程度; 3.采用以震级挡次为条件概率的空间分布函数,刻画地震带内各潜在震源区之间发生相应震级挡次地震的相对危险程度,使区划结果更好地反映地震活动在时间和空间上不均匀性分布的特点; 4.在地震危险性分析计算中,引入了方向性函数项,使得分析模型更接近我国地震震源的实际情况.      

Probabilistic Appraisal of Earthquake Hazard Parameters Deduced from a Bayesian Approach in the Northwest Frontier of the Himalayas

A straightforward Bayesian statistic is applied in five broad seismogenic source zones of the northwest frontier of the Himalayas to estimate the earthquake hazard parameters (maximum regional magnitude M _max, β value of G–R relationship and seismic activity rate or intensity λ). For this purpose, a reliable earthquake catalogue which is homogeneous for M _W ≥ 5.0 and complete during the period 1900 to 2010 is compiled. The Hindukush–Pamir Himalaya zone has been further divided into two seismic zones of shallow (h ≤ 70 km) and intermediate depth (h > 70 km) according to the variation of seismicity with depth in the subduction zone. The estimated earthquake hazard parameters by Bayesian approach are more stable and reliable with low standard deviations than other approaches, but the technique is more time consuming. In this study, quantiles of functions of distributions of true and apparent magnitudes for future time intervals of 5, 10, 20, 50 and 100 years are calculated with confidence limits for probability levels of 50, 70 and 90 % in all seismogenic source zones. The zones of estimated M _max greater than 8.0 are related to the Sulaiman–Kirthar ranges, Hindukush–Pamir Himalaya and Himalayan Frontal Thrusts belt; suggesting more seismically hazardous regions in the examined area. The lowest value of M _max (6.44) has been calculated in Northern-Pakistan and Hazara syntaxis zone which have estimated lowest activity rate 0.0023 events/day as compared to other zones. The Himalayan Frontal Thrusts belt exhibits higher earthquake magnitude (8.01) in next 100-years with 90 % probability level as compared to other zones, which reveals that this zone is more vulnerable to occurrence of a great earthquake. The obtained results in this study are directly useful for the probabilistic seismic hazard assessment in the examined region of Himalaya.     

Conditional Probability Approach of the Assessment of Tsunami Potential: Application in Three Tsunamigenic Regions of the Pacific Ocean

We develop stochastic approaches to determine the potential for tsunami generation from earthquakes by combining two interrelated time series, one for the earthquake events, and another for the tsunami events. Conditional probabilities for the occurrence of tsunamis as a function of time are calculated by assuming that the inter-arrival times of the past events are lognormally distributed and by taking into account the time of occurrence of the last event in the time series. An alternative approach is based on the total probabilitiy theorem. Then, the probability for the tsunami occurrence equals the product of the ratio, r (= tsunami generating earthquakes/total number of earthquakes) by the conditional probability for the occurrence of the next earthquake in the zone. The probabilities obtained by the total probability theorem are bounded upwards by the ratio r and, therefore, they are not comparable with the conditional probabilities. The two methods were successfully tested in three characteristic seismic zones of the Pacific Ocean: South America, Kuril-Kamchatka and Japan. For time intervals of about 20 years and over the probabilities exceed 0.50 in the three zones. It has been found that the results depend on the approach applied. In fact, the conditional probabilities of tsunami occurrence in Japan are slightly higher than in the South America region and in Kuril-Kamchatka they are clearly lower than in South America. Probabilities calculated by the total probability theorem are systematically higher in South America than in Japan while in Kuril-Kamchatka they are significantly lower than in Japan. The stochastic techniques tested in this paper are promising for the tsunami potential assessment in other tsunamigenic regions of the world.     

概率方法应用于地震短期预测的探索

根据爆发地震平静两项活动性前兆的统计结果,对地震发生的背景概率、条件概率和概率增益进行了估计,给和北地震发生前发震概率逐步增加时间过程,由背景概率Ｐ（Ｅ）增至中期前兆Ａ出现后的条件概率Ｐ（Ｅ／Ａ）,再增至短期前铛Ｂ（平静）出现后的联合条件概率Ｐ（Ｅ／Ａ）。结果表明,在１９９７年１２月１７日后的一个月内,华北地区发生６级以上的条件这３８％,概率增益超过２０,对概率预测结果的使用进行了探讨,提出应充分     

基于数学建模的潜在地震破裂面源检测方法研究

大多数地震破裂面源检测方法都是通过简化地震震源,将地震震源表示成线源或者点源,无法有效描述地震带地震破裂面源产状和大小,不适用地震震级较大的情况下地震危险性检测。因此提出基于数学建模的潜在地震破裂面源检测方法,在地震震级较大时仍能检测出地震危险性概率。选取适宜的地震基岩水平峰值加速度衰减关系,分析地震震级、破裂长度、破裂宽度相互关系,确定地震引起的潜在地震破裂面源大小,计算给定地震动小于在场点处产生地震动的概率,将该概率同地震动加速度衰减关系结合,得到地震动年超越概率,分析地震危险性。经过实验检测发现,所提方法检测出的年超越概率与峰值加速度、最大震级有关,该概率能精准表示地震带地震破裂面源产状和大小,说明该方法检测地震危险性是合理的。     

大青山山前活动断裂带分段与潜在震源区划分

潜在震源区的划分主要包括潜在震源区范围的划定以及震级上限的确定,目前遵循地震构造类比和地震活动重复等原则。而活断层的分段特性也是潜在震源区划分时必须考虑的一个重要因素。大青山山前断裂带至今有3种不同的分段方案,文中比较分析了前人对大青山山前断裂带的分段,并在此基础上对大青山及山前盆地的潜在震源区作了新的划分。鄂尔多斯块体周缘被拉张性断陷盆地围绕,这些断裂系地震构造相似,且除呼包盆地外均有历史8级以上地震记录。文中将大青山山前断裂带与鄂尔多斯块体周缘断裂系进行了构造对比,特别是与华山山前断裂进行了断裂活动性定量对比,得出雪海沟到土左旗段的震级上限为8级,断裂两端潜源震级上限均为7.5级     

根据截断的G-R模型计算东北地震区震级上限

震级上限是指一个地区可能发生地震的最大震级,其概率意义为发生超过该震级地震的概率几乎为0.在有些地区,由于对其内部的地震构造研究和认识存有局限性,很难根据构造或者地质学的原则来确定震级上限.因此,根据数学模型,采用统计手段,使用地震活动性资料来计算震级上限的估计值是一种可行的方法.本文根据截断的G-R关系模型,采用最大似然计算方法,使用东北地震区的地震目录,计算了东北地震区震级上限,结果表明东北地震区的震级上限应为M_u=7.5左右.计算中我们考虑了不同震级的转换、震级误差的修正以及计算方法的影响.最终结果表明,不论采用何种方案进行计算,东北地震区的震级上限值均始终保持在7.5左右,这说明我们采用本文中方法计算得到的东北地震区的震级上限值是合理可信的,同时也说明在以往的研究中对东北地震区震级上限的估计大都是偏小的.