1998年5月29日皮山县6.2级地震烈度分布特征及损失评估

１９９８年５月２９日皮山县发生６．２级地震,震中距皮山县城约３９ｋｍ,震源深度为３２ｋｍ,烈度分布区为北西－南东走向的椭圆形,极震区烈度为Ⅶ度,个别点为Ⅷ度,地震使皮山县县城,９个乡,２个镇,２个农场,墨玉县部分地区遭到不同程度的损失。共计受伤人数为２６人,其中重伤为２人,无家可归者人数为５５６６人,１３９２户,牲畜死亡４４５４头。地震造成的直接经济损失达５４８６．７５万元。     

地震间隙图像与地震大趋势

分析了几个区域的地震间隙图像特征及其与地震大形势的关系。本世纪６０年代前全球 历了大震活跃期,地震间隙基本保持平稳均匀分布,之后活动减弱、转平静。     

用准周期（PP）方法预测地震序列中早期强余震

研究了地震序列的准周期性,提出了预测早期强余震发生时间的准周期方法及其定量预报指标,同时进行了回溯性预报检验,Ｒ值评分为０．４５。表明该方法具有一定的预报效能。     

1994年9月16日台湾海峡7.3级地震震源过程的研究

采用数字化台网Ｐ波波形资料及台湾台网Ｐ波初动方向资料,研究了１９９４年９月１６日台湾海峡７３级地震及邻近地区（北纬２１～２６°,东经１１５～１２０°）ＭＬ≥５８级共５次地震的矩张量解及震源参数。结果表明,这次７３级地震的矩张量解以双力偶成分为主,是断层面接近ＮＷ走向的正断层。断层面的走向与大震前地震的条带分布走向及余震分布显示的破裂图象较相象,震源机制的张应力轴接近水平,近ＮＥ走向;压应力轴几乎垂直,近ＮＷＷ走向,似乎表明这次地震是受菲律海板块向欧亚板块北西向挤压的力源控制。从Ｐ轴接近竖直而Ｔ轴接近水平来看,发震断层为强烈拉张性正断层,可能还同时存在垂直向上的应力作用。其它４个强震的震源机制解与７３级大震的差别较大。这些地震震源机制解的复杂性,表明台湾海峡地震序列的发展过程比较复杂。     

Preliminary study on weathering and pedogenesis of carbonate rock

South China is the largest continuous distribution area of carbonate rock in the world. The origin of the soils over the bedrock carbonate rock has long been a controversial topic. Here further exploration is made by taking five soil profiles as examples, which are developed over the bedrock dolomitite and limestone and morphologically located in upland in karst terrain in the central, west and north Guizhou as well as west Hunan, and proved to be the weathering profiles of carbonate rock by the research results of acid-dissolved extraction experiment of bedrock, mineralogy and trace element geochemistry. Field, mineralogical and trace element geochemical characteristics of weathering and pedogenesis for carbonate rock are discussed in detail. It is pointed out that weathering and pedogenesis of carbonate rock are important pedogenetic mechanisms for soil resources in karst area, providing a basis for further researches on the origin of soils widely overlying bedrock carbonate rocks in South China. Project supported by the National Natural Science Foundation of China (Grant No. 498330003) and National Key Basic Research Project (Grant No. 95pre-39).     

Dynamic analysis on structures base-isolated by a ball system with restoring property

A computational model with its analysis method for base-isolated structures by a ball system with restoring property under seismic force is proposed in this paper, and the programs using numerical integration method and incremental harmonic balance method are developed. The analysis method is verified by shaking table test results of a three-storey masonry model. With these programs, the effect of some factors on the aseismic behaviour of base isolation system are analysed, and the comparison of seismic response between structures with and without base isolation is made. Results of both theory and test show that the above-mentioned base isolation system has apparent advantages over the traditional aseismic structures. © 1998 John Wiley & Sons, Ltd.     

Quantitative biostratigraphy and species evolutionary sequence

Introduction of species evolutionary sequence into the quantitative biostratigraphy is a significant work, either for studying biologic evolution or for making stratigraphic correlation and reconstructing geologic history. The quantitative biostratigraphy is to determine biostratigraphic event sequences by using probabilistic analysis. The evolutionary sequence systematics can efficiently ascertain species evolutionary sequences. Two methods have been proposed to determine the sequence of species-disappearance events: (1) species extinction events can be closed by last occurrence events using quantitative biostratigraphic analysis; (2) the duration of a species may be approximately replaced by the duration of its parent species. To combine these two methods for determining the sequence of species disappearance is the best way up to now. A consulting standard sequence that consists of the speciation sequence of Permian waagenophylloid corals and the biostratigraphic event sequence of other important fossils in Permian is used as an example. The group spearman rank-correlation test is used to test the consulting standard sequence by comparing four types of calculations and two kinds of sequences and to find abnormal events. Based on the found abnormal events in the test, the consulting standard sequence is revised to deal with different conditions. Sequences of speciation and species-disappearance, and species duration are determined. Application of species evolutionary sequence to quantitative biostratigraphy can largely improve the quality of biostratigraphic event sequence. In stratigraphic correlation, furthermore, event sequences have higher precision than range biozones.     

Sinistral Strike-slip Movement Along Western Terminal Segment of the Active Daqingshan Piedmont Fault, Inner Mongolia, China

There are 18 gullies displaying sinistral contortions to different degrees along the western terminal segment about 10 km long of the active Daqingshan piedmont fault near the Donghe District, Baotou City. The contortion amount of gullies ranges from 20 m to 300 m. The contortion and length of the gullies are in direct proportion. The relation between piedmont terraces and gullies indicates that the gullies with upper reaches of about 1 ～ 5 km long and those smaller than one kilometer were formed at the end of Late Pleistocene and Holocene.Meanwhile, sandy gravel layer of alluvial-proluvial sediment on the upthrown wall is directly in contact with yellow clayey sand of the downthrown wall. During the Holocene, the sinistral strike-slip rate along the western terminal segment of the active Daqingshan piedmont fault reached 5 mm/a from age data of dislocated sediments. The evolutional mechanism of the active Daqingshan piedmont fault is also discussed in the paper.     

Characteristics and Implication of the Earthquake Swarm Occurred in Fuzhou in September 1999

on Septmeber 23,1999,an earthquake swarm occured in Fuzhou,Because the swarm occurred in the region where earthquaks occurred scarcely before and very close to the center of the city as well as shortly after the Jiji earthquake with Ms7.6 in Taiwan,September 21,1999,has aroused interest broadly.In this paper,we analyzed the characteristics of spatial and temporal distribution of the earthquake swarm and validated magnitude-number constituent of the swarm is special.In present theory,the earthquake swarm means that a small scale macro original rupture has formed in the layer of the crust in Fuzhou region where moderately strong earthquake risk exists.     

Morphological responses ofLimnocythere inopinata (Ostracoda) to hydrochemical environment factors

Living ostracod and hydrochemical samples were collected synchronously from more than 50 lakes and small water body in the eastern edge area of the Tibetan Plateau, Northern Tibetan, Southern Tibet and mid-Tibet. The comparison of the adult body length ofLimnocythere inopinata and hydrochemical parameters of their habitats shows that a quantitative relationship exists between the adult body length and salinity expressed as conductivity. An empirical formula to reconstruct paleosalinity is suggested first and applied to salinity reconstruction of CE-2 core from Cuoe Lake, Tibet. The method is verified by comparing its outcome with results of other environment reconstruction methods.