Theory and Experimental Results about the Application of Remote Sensing to Earthquake Prediction

In this paper,the theory for applying remote sensing to earthquake prediction has been elucidated and an experiment has been made.Through the experiment,it has been found that the characteristics and temperature of infrared radiant of rocks vary as a function of rock stress,the order of magnitude of radiance variation is 10-5(W/cm2 sr um),the amount of variation of the radiant temperature is 0.2℃~0.8℃ and some significant precursor information has been discovered.The experiment has verified preliminarily that the advanced technology of remote sensing can be applied to earthquake prediction.     

Assessment of the role of slit as a safety valve in failure of levees

The development of a narrow channel or slit due to piping just underneath the base of levees channel has been reported to be useful to withstand the increase in the head beyond critical head conditions. Also, the maximum slit length has been emphasized to be up to half of the base width. By developing a model of critical head considering slit, it is found that the critical head can increase with the development of slit length only under certain conditions. Analysis of piping failure data indicates that the critical head expressions considering slit length constitute a potentially useful model for critical head.     

SHRIMP zircon U-Pb dating and its geological significance of Chibaisong gabbro in Tonghua area,Jilin Province,China

The basic dykes are widely distributed in the Tonghua area, among which the Chibaisong No.1 gabbro has attracted many geologists’ attention to the copper-nickel sulfide deposit within it. However, its formation time has been controversial all the time. Most geologists considered that it could be formed at the late Archean or the Paleoproterozoic[1]1), while some other geologists contended that it might be formed in early Yanshannian of Mesozoic2). The forming time of the basic dyke swarm i…     

Constraints on the Archean atmospheric oxygen and sulfur cycle from mass-independent sulfur records from Anshan-Benxi BIFs, Liaoning Province, China

The Archean atmospheric oxygen concentration and sulfur cycle was long debated. The banded iron formation (BIF) is a special type of the sedimentary formation, which has truly recorded the atmospheric and oceanic conditions at that time. In this study, the composition of multiple sulfur isotope (δ 34S/δ 33S/δ 32S) for sulfides bedded in the Archean (~2.7 Ga) BIFs, in Anshan-Benxi area of Liaoning Province has been measured. The value of △33S varies from -0.89‰ to 1.21‰, which shows very obvious mass-independent fractionation (MIF) signatures. These non-zero △33S values indicate that the Archean sulfur cycles are different from what it is today, which have been deeply influenced by gas phase photochemical reactions. Algoma-type BIFs which are closely related to the volcanic activity have negative △33S value, however, Superior-type BIFs which are far away from the volcanic center have positive △33S value. The δ 34S varies in a large range from -22.0‰ to 11.8‰, which indicates that the bacteria reduction activity has already existed at that time, and that the oceanic sulfate concentration has at least reached 1 mmol/L in local areas. Combined with the contemporaneous existence of the hematite, magnetite and the occurrence and preservation of the sulfur MIF, it can be inferred that the Archean atmospheric oxygen level must be at 10-2―10-3 of the present atmospheric level (PAL).     

Estimation of Potential Risk of Reservoir-Induced Earthquake for the Proposed Hydroelectric Project on the Yangtze Gorges

The proposed hydroelectric project on the Yangtze Gorges will be one of the largest power stations in the world.The problem of induced seismicity to the project has attracted much attention throughout China and the world.A research program has been carried out by the State Seismological Bureau of China.Based on the size of the reservoir and the lithology,geological structure,permeability,stress state,and previous seismicity in the region,the potential risk of reservoir-induced seismicity has been estimated.The results suggest that,after impoundment in the reservoir area,the possibility of induced seismicity cannot be completely ruled out.The areas with potential risk may be in some gorges composed of karstified carbonate and plutonic granite around the dam site.However,the magnitude is expected to be limited owing to the small dimension of the induced seismogenic faults.     

Synthetic Model for Prediction Seismic Risk in About 10 Years

In this paper, the relation that strong earthquakes and seismo-geological conditions bear with precursory phenomena has been analyzed. The information content concerning the long-term (i.e., a decade) seismic risk that various precursors can provide has been estimated by using the quantitative judgment method. On such a basis, a synthetic probability model for predicting the strong earthquake risk in about 10 years has been suggested. With the northern part of North China used as the test region, the feasibility of the model which is used for medium-term to long-term prediction has been proved.     

A Physical Method of Analyzing theMechanism of Continental StrongShocks from Crustal Movement

In order to analyze the mechanism of continental strong shocks from the angle of crustal movement using the data of repeated geodetic survey, this paper has proposed a physical method; it analyzes the mechanism of density change due to the occurrence of strong shocks by use of the physical quantity that reflects the time change of crustal density. ( 1 ) The general theory of the time change of density in the earth‘ s interior and the theory of the time change of single layer density have been introduced, and an algorithm of stepwise iteration has been proposed; (2) The effect of the change of single layer density caused by fault dislocation has been analyzed in brief; (3) The characteristics of the time change of crustal density in the south of the seismogenic region before the 1996 Lijiang earthquake with ML = 7.0 have been studied; (4) The precursor model or causal mechanism of strong shocks possibly existing in the time change of crustal density has been investigated preliminarily.     

Discovery of seismites in Upper Sinian stratiform lead-zinc deposits in Dadu River valley, Sichuan, China: Implication for ore genesis

A number of lead-zinc sulphide deposits have been discovered in recent years in dolo- mitic rocks of the Upper Sinian Dengying Formation in the Dadu River valley region, Sichuan Province, China. The lead-zinc mineralization is closely associated with a black siliceous exhalite that has been traced over 50 km of strike. This makes Dadu River valley the most extensive stratiform non-ferrous sulphide horizon having been discovered to date in China. In a previous study by the first author (LIN), these deposits were recognised as belonging to the broad spectrum of lead-zinc sedimentary exhala- tive (SEDEX) deposits. In this paper, seismites and seismogenetic structures occurring in close association with the Dadu River valley mineralized zone are described. The close spatial and temporal relationship between the seismites and mineralization provides strong evidence for the hypothesis that the lead-zinc SEDEX deposits formed in direct response to earthquake activities around the Sinian-Cambrian boundary. The earthquakes are postulated to be an effective dynamic mechanism for triggering the upward migration of deep circulating ore fluids along synsedimentary growth faults and their exhalation onto the sea-floor to form the extensive deposits of stratiform lead-zinc sulphide ore.     

Impact of climate change on sediment yield for Naran watershed,Pakistan

In this paper, the site-specific impact of climate change on sediment yield has been assessed for the Naran watershed, Pakistan. Observed data has been gathered for period 1961–2010 and HaDCM3 GCM predictors of SRES scenarios A2 and B2 have been downloaded. Future precipitation and temperature time series have been statistically downscaled for time horizon 2011–2040 and 2041–2070. Downscaled data show both increasing and decreasing changes with respect to the observation. Potential sediment yield for future related to climate change has been simulated. The results show that the both snowy and monsoon seasonal stream discharges are expected to increase. This will lead to increase in annual sus-pended sediment yields. Percentage-wise, a less discharge and more sediment yield are expected during the early summer. The study concluded that the climate change and variability are influencing the watershed, and suspended sediment yield is likely to increase in the future.     

A STUDY OF THE RECENT TECTONIC ACTIVITY IN JIANGSUSHANDONG-ANHUI AREA

In this paper two vertical deformation maps have been drawn, based on the accurate leveling data of 1950-1980, in Jiangsu-Shandong-Anhui area. Along combining with neotectonic, geological basis and crustal deformation data, an analysis of the recent tectonic activity in the studied area has been made,and some conclusions have been drawn as follows: (1) The Tancheng-Lujiang fault zone across the studied area is the key tectonic element in recent tectonic activity, and the crustal deform...更多ation is controlled by the fault zone. (2) A study of the two deformation maps shows that the section of the Tancheng-Lujiang fault zone in this area is a creeping section, but both ends of the section are locked parts. The stress concentration ought to be accumulated in these parts. (3) Difference between the two maps suggests that the activity character of the fault zone is right lateral slip during 1950 to 1970, but reverse activity has occurred since 1982 to 1983. This suggests that the most intense earthquake in East 还原 【Abstract】 In this paper two vertical deformation maps have been drawn, based on the accurate leveling data of 1950-1980, in Jiangsu-Shandong-Anhui area. Along combining with neotectonic, geological basis and crustal deformation data, an analysis of the recent tectonic activity in the studied area has been made,and some conclusions have been drawn as follows: (1) The Tancheng-Lujiang fault zone across the studied area is the key tectonic element in recent tectonic activity, and the crustal deformation is controlled by the fault zone. (2) A study of the two deformation maps shows that the section of the Tancheng-Lujiang fault zone in this area is a creeping section, but both ends of the section are locked parts. The stress concentration ought to be accumulated in these parts. (3) Difference between the two maps suggests that the activity character of the fault zone is right lateral slip during 1950 to 1970, but reverse activity has occurred since 1982 to 1983. This suggests that the most intense     

Characteristics of Fault Activity in the Taiyangshan Uplift Area in Hunan,China

Lying on the west edge of Dongting Lake, the Taiyangshan area in Hunan Province is part of a hilly region which has uplifted since the Late Cenozoic. According to field investigation of the six existing faults in the Taiyangshan area, we found that four of them are not active in the Quaternary, and that the Gangshi-Hefu fault is likely to have been active in the early Mid- Pleistocene. The geological evidence derived suggests that the Xiaowupu fault was active from the late Mid-Pleistocene to the early late-Pleistocene. It cut the stratum with a TL age of 123 ± 10ka BP and has the property of thrusting. The research results are of great significance for understanding the seismogenic structure of the Changde earthquake with M63/4 in 1631.     

Establishment of the GPS Monitoring Network in North China, the Relation of Horizontal Crustal Movement to Stress Field and Seismicity

In the paper, the establishment, measurement, data-processing program and monitoring accuracy of the GPS seismic monitoring network in North China, especially in the Capital-Circle area, have been presented briefly. The relation of horizontal crustal deformation to tectonic movement, stress-field variation and seismicity has been analyzed in detail. The results indicate that the accuracy of GPS measurement has reached the order of 10-9 and the annual rate of horizontal crustal deformation in North China is about 4 ~5 mm. Horizontal crustal movement is a direct indication of the regional stress field. Therefore, by monitoring the time-sequence variation of horizontal crustal motion, it would be possible to investigate the change in the stress field, to analyze the tendency of seismicity and to determine the seismogenic zones.     

Effect of geofoam as cover material in cut and cover tunnels on the seismic response of ground surface

In recent years,special attention has been given to the effects of underground spaces and structures on the seismic response of adjacent ground.Nevertheless,to the best of the authors′knowledge,no method has yet been considered to reduce these effects in technical literature.The present study aims to investigate the role of geofoam as the cover material in cut and cover tunnels on the seismic response of the ground surface.For this purpose,a numerical study was performed using FLAC 2D,a finite difference software,and verified against previous studies.The effects of parameters such as the geofoam type,thickness of the geofoam blocks and interfaces between the blocks,on the ground surface amplification pattern were investigated.Parametric studies demonstrate that the geofoam has a strong potential to attenuate the seismic horizontal movements of the ground surface.As the thickness of the geofoam blocks is decreased,its attenuation ability is increased.It was also determined that the interface between the geofoam blocks plays a key role in the attenuation of the aboveground seismic responses.Based on the results,it was concluded that geofoam is a proper material to attenuate seismic amplifications at the ground surface,induced by underground tunnels.