地热正常动态特征的研究

为了研究地热正常动态特征,收集了226个地热前兆观测台站的数据,建立了地热前兆应用数据库。 通过对地热前兆台站观测资料的整理分析,将地热正常动态分为地热的长期正常动态和地热的短期动态两类,归纳出6种类型的地热长期正常动态和4种类型的地热短期正常动态,并结合观测点处的水文地质情况,对不同的地热正常动态类型的成因进行了初步分析。     

Molodensky边值问题中解析延拓法g1项的小波算法

运用小波分析理论研究了Molodensky边值问题的计算方法，论证了该类问题的计算对于精化重力场模型的意义，即可以放弃考虑地球密度的各种重力改正。针对解析延拓法，证明g1项奇异积分在Chauchy主值意义下的存在性。计算结果表明，该算法具有快速、准确的特征，特别适用大范围计算g1项的值，这为精化重力场提供了现实可能性。     

应用非线性动态门限反馈(MF)模型剖析鞍山地应力异常

为论证鞍山地应力异常的可靠性,应用ＭＦ模型对其干扰和异常作了计算,发现１９９３年以来的长趋势及部分短期变化主要是干扰引起的,悬空元件和同期的室温、水位测值可作为其它受力元件的主要干扰因子．但在某些时段鞍山地应力仍有一定的趋势异常显示．     

An improved time series model for monthly stream flows

This study aims to develop an improved time series model to overcome difficulties in modeling monthly short term stream flows. The periodic, serial dependent and independent components of the classical time series models are improved separately by information transfer from a surrounding long term gauging station to the considered flow section having short term records. Eventually, an improved model preserving the mathematical model structure of the classical time series model, while improving general and monthly statistics of the monthly stream flows, is derived by using the improved components instead of the short term model components in the time series modeling. The correlative relationships between the current short term and surrounding long term stations are used to improve periodic and serial dependent behaviors of monthly flows. Independent components (residuals) are improved via the parameters defining their theoretical probability distribution. The improved model approach is tested by using 50 year records of Göksu-Himmetli (1801) and Göksu-Gökdere (1805) flow monitoring stations located on the Ceyhan river basin, in south of Turkey. After 50 year records of the station 1801 are separated into five 10 year sub series, their improved and classical time series models are computed and compared with the real long-term (50 year) time series model of this station to reveal efficiencies of the improved models for each subseries (sub terms with 10 year observation). The comparisons are realized based on the model components, model estimates and general/monthly statistics of model estimates. Finally, some evaluations are made on the results compared to the regression method classically applied in the literature.     

重庆地震台地倾斜观测资料分析

分析了重庆地震台地倾斜观测资料,结合重庆辖区内10多年来的地震活动,提取地倾斜观测异常,为地震预测提供前兆参考。资料分析认为:对于发生在震中距为80~120km的5.0级以下地震,地倾斜观测地震异常少;5.0级以上的地震,地倾斜观测有异常记录,地震中期异常往往表现为震前几个月倾斜量的较大幅度变化,短期异常多数表现为震前差分值的低值变化(在均值附近变化,幅值较小,持续时间20d左右),部分表现为差分值震前突跳,临震异常主要是震前几天短周期波动变化。     

南黄海6.1级地震前地震波动力学特征变化指标的研究

研究了南黄海６１级地震前地震波动力学特征的变化,诸如Ｓ波、Ｐ波频谱的峰值频率,拐角频率,相对频带宽度,相对频谱峰值,波速比,Ｐ波初始部分波形的时间线性度及Ｐ波初始段平均半周期等。结果表明：震前地震波动力学各特征指标均有一定的异常变化,且大多能较好地反映出约０５ａ左右的前兆异常。指出地震预报中同时使用这些指标的可行性。     

小波分析在库尔勒地震台气氡资料处理中的应用

选取库尔勒台2008～2010年气氡观测资料,利用尺度为4的db4小波对其进行处理,并分别对其低频和高频短期异常进行研究。结果表明,该方法对不同频率的信息识别功能较强,有助于将数据的趋势变化和局部变化分离,能够有效地识别与消除干扰因素,提取短期异常,是地震前兆数据处理的一种有效方法。结合震例研究表明,台站周围200km范围内4级地震发生前3～5个月气氡出现异常。     

阿图什6.9级地震序列特征和监测预报

阿图什６．９级地震前，新疆维吾尔自治区地震局做了较为准确的中、短期预报。地震后，通过对余震序列和震区地质构造及历史地震的类比与分析，认为该地震属主震一余震型，并根据资料分析对后续强余震做了准确预报。     

渤海盆地地震周期模式和地震危险性分析

根据历史地震资料,分析了渤海中部与胶辽海峡的地震周期模式。结果表明,时间可预测模式比滑动可预测模式更接近胶辽海峡历史地震的时间序列特征。按时间可预测模型外推,胶辽海峡下次强震可能发生在２１世纪初期,渤中地区历史地震序列特征复杂,一些关键地硅的震级修订造成预测模型改变,使渤中地区地震发生时间的不确定性增大,不利于渤海盆地地震的长期预测。影响长期预测准确性的主要因素是历史地震震级的可靠性、准确性、直接     

哈尔滨市延寿地震台竖直摆倾斜仪资料分析

介绍了哈尔滨市延寿地震台竖直摆倾斜仪的工作状态,列举了该仪器记录到的多次同震应变阶。分析认为:这种阶跃变化反映了地震因释放应变能而改变了地壳的应变场;从阶变图象可以看出:中强远震的同震阶变幅度较小,中强近震同震阶变的相对幅度较大,同等震级震中距越小,阶变幅度也越大。证明了近震对观测点(台站)附近区域应力场改变大于远震。同时,展示了2005年7月25日黑龙江省林甸县M5.1级地震的短期异常及临震异常变化图象,发现短期异常和临震异常的形态非常类似,但同一方向(分量)仪器对两次异常的响应程度却截然不同,这可能与此次地震孕育过程不同阶段的地壳应力调整和应力场变化密切相关。     

1998年云南下关4.7级地震预报

1998年12月2日云南下关发生了4．7级震群，大理州地震局依据地震活动、前兆异常及宏观异常情况作出了趋势、中短期和临震的预报；对震前的各类异常作了分析，探讨了预报中存在的问题。     

2020年3月20日蒙古MS 5.9地震前地倾斜资料异常特征分析

采用形态法和小波分析法,分析2020年3月20日蒙古M_S 5.9地震震中距400 km范围内巴里坤、富蕴和芨芨台地震台倾斜观测资料的震前异常特征。结果表明：3套资料在震前均具有明显的中短期异常,分别表现为反向趋势变化、破年变形态和倾斜速率减缓的特征;使用db4小波对3套资料进行分析,其6—9阶在震前出现周期为几天至几十天的低频短期异常,同时巴里坤水平摆倾斜仪EW分量8—9阶趋势异常较显著。     

新疆北天山地区震磁预报研究

采用统一的分析方法和标准从北天山地区的地磁场总强度资料中提取异常信息．结果表明，在区内发生的一些中强地震前，震中周围的台站存在较明显的中、短期异常．     

小波分析在永安地震台前兆观测资料处理中的应用

利用小波分析方法对永安台前兆观测资料进行处理,结果表明该方法能够有效地将数据波动、脉冲干扰和地震同震波从原数据中分离出去,并且能够得到清晰的前兆数据原始变化趋势,可以使今后各种长短期震前异常的识别变得更加容易。     

半个世纪来热带海洋风暴对中国大陆的影响

本文利用美国海军台风警报中心（JTWC）提供的1945～2002年热带风暴路径资料统计分析了西北太平洋（NWP）和中国南海（SCS）风暴生成及登陆中国大陆热带风暴的时空演变特征.季节变化上，NWP风暴登陆主要集中于6～11月，SCS风暴影响主要集中在6～9月，但后者登陆总数比前者少.西北太平洋风暴在东南沿海(27°N，120°E)附近登陆的频次最高，在此以北随纬度急剧下降.年际变化时间尺度上，登陆大陆的风暴年总数与来自南海的年风暴数成正比.登陆我国的热带风暴年频数有明显的区域差异和显著的2～7年振荡.长期趋势上，两个海域的风暴年生成频数和登陆大陆的年风暴频数在58年中总体呈线性增长趋势，其中登陆频数增长趋势相对缓慢，但近几年登陆风暴数与生成风暴数都表现出减少的趋势.生成频数和登陆频数都呈现出年代际变化，其年代转换发生在1960、1970年和1990年前后.     

泾阳4.8级地震前后泾阳地震台形变观测资料的异常分析

分析了泾阳地震台跨断层短水准及流动形变观测资料在 1998年 1月 5日泾阳MS4 .8地震前后的异常变化 .结果表明 ,该次地震前后泾阳台的形变资料出现了明显的短期异常及震后效应 .     

Recognition method for mid‐ to long‐term runoff forecasting factors based on global sensitivity analysis in the Nenjiang River Basin

Mid‐ to long‐term runoff forecasting is important to China. Forecasting based on physical causes has become the trend of this field, and recognition of key factors is central to recent development. Here, global sensitivity analysis based on back‐propagation arithmetic was used to calculate the sensitivity of up to 24 factors that affect runoff in the Nenjiang River Basin. The following five indices were found to be key factors for mid‐ to long‐term runoff forecasting during flood season: Tibetan Plateau B, index of the strength of the East Asian trough, index of the area of the northern hemisphere polar vortex, zonal circulation index over the Eurasian continent and index of the strength of the subtropical high over the western Pacific. The hydrological climate of the study area and the rainfall–runoff laws were then analysed in conjunction with its geographical position and topographic condition. The rationality of the results can be demonstrated from the positive analysis point of view. The results of this study provide a general method for selection of mid‐ to long‐term runoff forecasting factors based on physical causes. Copyright © 2012 John Wiley & Sons, Ltd.     

2003年8月21日盐源5.0级地震的预测与分析

20 0 3年 8月 2 1日 1 0时 1 7分 ,四川省凉山彝族自治州盐源县发生MS5 0地震。据四川省地震台网测定 ,微观震中为 2 7 4°N ,1 0 1 3°W ;震源深度为 5km。震前 ,根据片区各台前兆手段监测到的短临异常和西昌地震遥测台网记录到的前震活动 ,共同做出了一定程度的短临预测。地震监测、现场调查和震源机制解等分析方法表明 ,这次地震震源深度较浅、震中烈度相对较高 (Ⅵ度 ) ,等震线长轴方向为北北西向的椭圆形 ,烈度沿北北西、南南东方向衰减较慢 ,沿北东东、南西西方向衰减较快 ,是盐源弧形构造西则北西向断裂逆冲兼左旋走滑型断层活动的结果 ;本次序列的时序曲线和各项序列参数计算结果均表明它的余震衰减基本正常。     

Classifying the flow regimes of Mediterranean streams using multivariate analysis

Rivers in the Mediterranean region often exhibit an intermittent character. An understanding and classification of the flow regimes of these rivers is needed, as flow patterns control both physicochemical and biological processes. This paper reports an attempt to classify flow regimes in Mediterranean rivers based on hydrological variables extracted from discharge time series. Long‐term discharge records from 60 rivers within the Mediterranean region were analysed in order to classify the streams into different flow regime groups. Hydrological indices (HIs) were derived for each stream and principal component analysis (PCA) and then applied to these indices to identify subsets of HIs describing the major sources of variations, while simultaneously minimizing redundancy. PCA was performed for two groups of streams (perennial and temporary) and for all streams combined. The results show that whereas perennial streams are mainly described by high‐flow indices, temporary streams are described by duration, variability and predictability indices. Agglomerative cluster analysis based on HIs identified six groups of rivers classified according to differences in intermittency and variability. A methodology allowing such a classification for ungauged catchments was also tested. Broad‐scale catchment characteristics based on digital elevation, climate, soil and land use data were derived for each long‐term station where these data were available. By using stepwise multiple regression analysis, statistically significant relationships were fitted, linking the three selected hydrological variables (mean annual number of zero‐flow days, predictability and flashiness) to the catchment characteristics. The method provides a means of simplifying the complexity of river systems and is thus useful for river basin management. Copyright © 2015 John Wiley & Sons, Ltd.