The Paleoproterozoic meta-supracrustal rocks, known as the South Liaohe Group, is widely exposed in the southeast of Liaodong Peninsula. Its lower part is characterized by the extensive metavolcanic rocks. In this paper, we study the petrology and whole-rock geochemical data of the biotite plagioclase gneiss, amphibolite, and biotite leptynites, as well as the U-Pb dating and Lu-Hf isotope data of the zircons in these rocks. The aim is to restrict the petrogenesis of Jiao-Liao-Ji belt by researching their composition, the ages of formation and metamorphism of the protolith, and the petrogenesis. The structure, composition, and U-Pb ages of zircon indicate that the protoliths of the metavolcanic rocks in South Liaohe Group were formed at ca. 2.19 Ga, and they were affected by metamorphic events at 1.90 Ga. The element and isotope geochemical analysis show that the protoliths of these rocks were basaltic andesite-andesite, dacite, and minor rhyolite; most of them belong to sub-alkaline affinities with calc-alkaline evolution. The basic rocks have relatively low SiO₂ contents, enriched in MgO, TFe₂O₃, and light rare-earth elements(LREE), Cr, Co, and Ni, while depleted of heavy rare-earth elements(HREE) and high-field strength elements(HFSE, such as Nb, Ta and Ti), indicating a derivation from a partial melting of a depleted lithospheric mantle that had been altered by the fluids or melts derived from a subducted slab. However, the intermediate acid rocks have high contents of SiO₂ and low contents of MgO and TFe₂O₃, enriched in alkalis, Ba, Th, U and K, while depleted of Nb, Ta, P and Ti, indicating that the acidic rocks could have been derived from a partial melting of juvenile crust. Taking into account the regional geology, we consider that the metavolcanic rocks of the South Liaohe Group formed under an active continental margin, and the evolution of the northern segment of the Jiao-Liao-Ji belt was related to an arc-continent collision before the middle Paleoproterozoic.

The authors found the indicative characteristics of paleokarst reservoir in Yichuan-Huanglong area in the southeastern Ordos basin, after a comprehensive analysis combining with seismic, well logging, and core data. The core data demonstrate that the reservoir rocks are mainly gypsum-bearing dolomite and secondary limestone; the reservoir spaces are vugs in dolomite, relatively isolate caves,and fractures; the reservoirs are tight,the porosity varies from 0.30% to 11.54%,with an average of 3.90%, and the permeability varies from 0.002×10^-3 μm² to 15.450×10^-3 μm²,with an average of 0.710×10^-3 μm². Reservoir quality is affected by bedded karstification. The comprehensive analysis was further conducted based on paleo-geomorphology, depositional facies,and fractures. The results suggest that the western area of the Ordovician platform in Yichuan is a favorable target for exploration and development due to its high position in the paleo structure and bedded karstification in the reservoir.

In order to guide the deployment of drilling in dolomite reservoir of Sichuan basin. Based on oil and gas drilling core observation and description, field profile measurement and sample collection, combined with microscopic thin section identification、X-ray diffraction、physical parameter and geochemical characteristics analysis, we studied the reservoir sedimentary-diagenetic system about the dolomites in Changxing Formation of the eastern inland sea trough in Kaijiang-Liangping. It is considered that the platform margin reef and platform marginal shoal are the most important reservoir facies belts, The main reservoir lithology is of grain dolomite, biological reef dolomite,and crystalline dolomite. The most effective reservoir spaces are intergranular solution pores, intercrystalline pores,and super solution pores. The composite reservoirs with holes and seams are the best reservoir type. Comprehensive analysis showed that the sedimentary diagenetic system of the Changxing Formation has a good coupling relationship with dolomite reservoir in time and space. The distribution of Changxing Formation dolomite reservoir is controlled by the platform margin reef and platform marginal shoal facies, and the contribution of different diagenetic system to reservoir is different. Among them, the formation sealing brine and mixed hot brine diagenetic system are the foundation and key for reservoir formation:the former is of Type Ⅲ pores with low porosity and low permeability, and the latter is of TypeⅡ pores with middle porosity and permeability. The structural hydrothermal diagenesis system has the biggest contribution to the reservoir, which can form high quality Type I reservoirs.

A unique type of blended mouth bars was recognized in middle-deep fan deltas in the western slope of Nanpu Sag, Bohai Bay basin. Combined with logging and seismic facies, and blended mouth bars' sedimentary features, the authors investigated bars' form, distribution patterns, and the genetic mechanisms by systematic view and analysis of cores from middle-deep beds of the research area. The results indicate that the lithology combination of the blended mouth bar shows an overall vertical upward sedimentary sequence consisting of multiple small reverse and positive compound cycles, the features of deposition from gravity flow. In a plane view, these blended mouth bars develop usually in front of underwater distributary channels of fan delta, and they present usually the forms of ligule or leaf. On the section, these blended mouth bars mainly show banded form, lute-shaped form, reversed lute-shaped form, and spindle-shaped form along depositional dip. These bars are independent lentoid sand body on perpendicular to source direction. These special blended mouth bars are quite different from the normal mouth bars on the basis of their characteristics, so they are called blended gravity flow bars.

The evaluation criterion of tight sandstone reservoirs is not only the foundation to distinguish reservoir "sweet spot",but also the key and difficult point to explore tight oil. However,no unified understanding has been achieved so far. Taking the tight sandstone reservoirs of Quantou 4 Formation at the central depression in the southern Songliao basin as an example,we established the evaluation scheme of tight sandstone reservoirs on the basis of micro pore throat through integrating the subtle characterization of conventional mercury injection,constant-rate mercury injection, high-pressure mercury injection experiment,and other data. The results show that tight sandstone reservoirs in this area are characterized by small pore throats and poor physical property,whose reservoir space is dominated by the secondary solution pores. The reservoir permeability is mainly controlled by the large-radius pore throats whose volume are small. The larger the throat radius and the larger throat ratio is, the higher the permeability (K) of the tight reservoir and the better the quality. According to the differences of pore throat structures,tight sandstone reservoirs of Quantou 4 Formation at the central depression in the southern Songliao basin can be divided into four categories. Oil can be filled into the first,the second,and the third levels of tight reservoirs;and the first level of reservoirs (K=(0.1-1.0)×10^-3 μm²) are the best that can be taken as reservoir "sweet spots".

Heavy oil is characterized by its large viscosity, large-scale continuous accumulation, strong reservoir heterogeneity,and difficult for exploration etc. It is impossible to reveal the difference of heavy oil enrichment in 3D space, and to predict the distribution of the "sweet spots" by using the traditional volumetric method. Based on the geographic information technology,the spatial interpolation method is to take play as a basic evaluation unit to demarcate the distribution area of each unit so as to count and analyze the spatial distribution patterns of the four key parameters incl. reservoir thickness, oil saturation, porosity, and the recovery rate; and then based on actual situation to further select suitable interpolation methods (inverse distance weighted interpolation, Kriging interpolation method etc.), to achieve spatial superposition calculation of the grid maps of the key parameters, and finally to calculate the abundance map of heavy oil of each reservoir formation. This method can quantitatively characterize the spatial distribution of heavy oil resources, and confirm the "sweet spots" of heavy oil. We applied this method to evaluate the potential of heavy oil in the Zagros fold belt in Middle East. According to the evaluation results, the total recoverable heavy oil resources of the four plays (Triassic-Jurassic Butmah, Jurassic, Cretaceous and Tertiary) reaches about 14×10⁹ t. Among them, the Cretaceous play is the favorable exploration target in the future with 8.5×10⁹ t of recoverable heavy oil resources. According to an initial prediction, the "sweet spot" is located at the southwest of the basin.

In order to study the role of fault in the down oil-gas generation and upper accumulation, based on the study of oil source fault dominant channel transportation capability, the authors established a set of comprehensive evaluation parameters of oil source fault dominant channel transportation capability by using its development characteristics and the quality of the source rock, and then applied it into 10 major oil source fault dominant channels for the evaluation of their transportation capability in E₃d³ reservoir, Bohai bay basin, and Jizhong depress. The study shows that there are 10 major oil source faults of E₃d³ reservoir in Liuchu with 34 dominant channels developed. Of them, 8 channels with high transportation capability are mainly distributed in the northern Liuchu anticline, 15 channels with middle transportation capability are mainly distributed in Liuchunan anticline, and 11 channels with weak transportation capability are mainly distributed in the southern and eastern edges. These results are consistent with the current distribution of the oil-gas found in the north core of E₃d³ reservoir anticline and the middle section of Liuchu anticline. The method is proved to be useful for the comprehensive evaluation of an oil source fault dominant channel transportation capability.

In order to study the damage degree of fractures to caprock and its influence on oil and gas distribution in a fault developed zone in a petroliferous basin, based on the previous studies, we defined the comprehensive sealing ability of fractures and the comprehensive sealing capacity of mudstone caprock, and calculated the ratio of these two, and finally obtained the method for calculating the comprehensive damage degree of fractured mudstone caprock. This method was applied to calculate the comprehensive damage degree of K₁d₁ mudstone caprock in Huhenuoren structure in Bessie slope of Baer sag Hailar basin. The results show that the comprehensive damage degree of the F5 fault to K₁d₁ mudstone caprock is in the level of strong-stronger at the measuring site of No. 4, 6, 9, 10 and 11, but in weak level at the other measuring sites. In the site of No.4, 6, 9, 10 and 11 of the caprock with strong damage degree, no or little gas and oil appear in drilling well. The preservation of oil and gas is poor for the reason of strong caprock damage caused by fractures. In the measuring site of No.1-3, 5, 7,8 and 12-15 of the caprock with weak damage degree, the preservation of oil and gas is relatively better, and the near oil-bearing properties of well are industrial oil well or low production well. The comprehensive damage degree of F5 fault to K₁d₁ mudstone caprock is consistent with the K₁n₂ oil and gas show. It is proved that the method is feasible for study on the comprehensive damage extent of mudstone caprock by fault.

The Gumudi anticline is located at the north border of Fukang thrust belt, north piedmont zone of Bogeda Mountains. Combining with the outcrops, seismic and apatite fission track, we discussed the tectonic response of the sedimentary basin during the uplift of Bogeda Mountains. Vertically, the Gumudi anticline has dual structures:the layers below the Jurassic (J₂x) Xishanyao formation were formed in 150-130 Ma and 100-80 Ma; while Xishanyao formation (J₂x) and the above were formed in 30 Ma, with the features of propagation folds under faults breaking through. The results reflect that the multiple uplifts of Bogeda Mountains occurred after Late Jurassic, and the dual structure formation was formed earlier with shallower burial depth. The Gumudi anticline is a favorable area for oil and gas exploration in future.

Aerhada Pb-Zn deposit is one representative of those in Erlianhot-Dongwuqi polymetallic metallogenic belt. The orebodies occur mainly as veins and lenticular in shape in Angeryinwula formation,and are controlled by the NW striking faults. The ore-controlling faults underwent multiple tectonic activities, formed different mineral assemblages corresponding to the ore forming stages of (Ⅰ) quartz-arsenopyrite-pyrite stage,(Ⅱ) poor sulfide-quartz stage,(Ⅲ) polymetallic sulfide stage, and (Ⅳ) poor galena-fluorite-calcite stage. The ore-controlling faults are characterized essentially by the left slipping normal faults. The positions vertically along the steep trend and horizontally along the westward faults are the favorable place for lead and zinc ore body. The thickness of the alteration zone,the thickness of orebody and its high grade position are all agreed with the structural changing position of the fractures. Both the orebody and the alteration zone have a tendency to SW lateral prostration. According to this ore enrichment pattern, we suggest a further exploration in deep level of the ore mine. Based on a detailed geological investigation and the mineralization enrichment rule above,we evaluated and predicted the favorable locations on both sides and deep level of ore vein 1 in Aerhada deposit by using numerical simulation techniques; and circled six target areas.

The Yaojiagou molybdenum deposit is a newly discovered one in recent years in the ore field of Qingchengzi in Liaoning. It is located in the Yan-Liao Mo metallogenic belt in the northern margin of the North China craton. The quartz veins (UST)and quartz eyes in the Yaojiagou pluton are direct evidence of fluid exsolution from magma. Deposit alteration zonation is significant,and the molybdenum mineralization mainly exists in the potassic and skarn zones. After a microscopic observation,we found various abundant fluid inclusions,including single-phase aqueous (PW-type), two-phase aqueous (W-type), three-phase CO₂ (C-type), pure CO₂ (PC-type),and daughter mineral-bearing inclusions (S-type) in which the daughter minerals are hematite, chalcopyrite,and some other unknown minerals with no halite. The fluid evolution in this deposit are:1) the early quartz eye stage with the homogenization temperature of 211.4-515.4℃, salinity of 0.8%-19.2%,and rich in CO₂; 2) the quartz veins mineralization stage with the homogenization temperature of 179.5-424.5℃ and salinity of 2.4%-21.5% in NaCl-H₂O-CO₂ system;3) the late quartz veins stage with the homogenization temperature of 167.8-353.3℃ and salinity of 3.4%-15.8% in NaCl-H₂O-CO₂ system;4) the latest calcite veins stage with the homogenization temperature of 132.5-234.1℃ and salinity of 0.9%-11.2% in NaCl-H₂O system;5)the UST quartz veins stage with the homogenization temperature of 158.6-381.7℃ and salinity of 1.6%-21.5% in NaCl-H₂O-CO₂ system, and this stage represents a immiscible fluid exsolution from a shallower intrusive magma with no mineralization. Wall rock alteration and fluid mixing are the main mechanisms of ore-forming metal elements precipitation,which lead to fluid temperature, pressure reduction, CO₂ escaping,and system rebalancing. We obtained the capture pressure of 124-180 MPa with the corresponding depth of 4.6-7.0 km during the ore-forming period by using the method of isochore intersection. It is relatively deeper than that of the other molybdenum deposits in the northern margin of the North China craton.

The Jinling dioritic pluton in west Shandong is mainly composed of pyroxene diorite and biotite diorite. The zircon U-Pb dating results reveal that the dioritic pluton was emplaced in Early Cretaceous(129.17±0.96) Ma and (130.15±0.65)Ma. The major element data show that the diorites contain low contents of SiO₂, K₂O, and high contents of Na₂O, Fe₂O₃, MgO, Mg^# and Al₂O₃. The Na₂O/K₂O ratios range from 1.08 to 2.96. The diorites are enriched relatively in sodium and alumina. The diorites have calc-alkaline characteristics according to the Ritttman index(1.95-2.96). The contents of Ni、Cr、Co are 99.00×10^-6-237.00×10^-6,270.00×10^-6-600.00×10^-6,19.00×10^-6 -44.00×10^-6 respectively, similar to the contents of mantle magma. The chondrite standardized REE curves show that they are enriched in light REE, and depleted of heavy REE with weak Eu anomaly (0.91-1.12). The diorites are enriched in large ion lithophile element (LILE) Ba, K, Sr, and high field strength elements (HFSE) Nd, while depleted of high field strength elements (HFSE) Rb, Nb, Ta, and Zr. The residual ancient zircons (~2.5 Ga) in the sample (N₁) indicate a mix of ancient lower crust occurred in the source area. The Jinling pluton might be formed under a lithospheric extension related to the rollback of the subducted Pacific plate, and the magma was the mixing product of the siliceous crust melted through underplating of basaltic magma, and the mantle enriched basaltic magma.

The Xiaoyao granodiorite pluton intruded into Neoproterozoic Paleozoic marine sedimentary strata in Jixi County, south Anhui Province. The LA-ICP-MS zircon U-Pb isotopic data yield weighted mean ages of (149.3±2.3) and (148.6±1.9) Ma, indicating the magma was emplaced in Late Jurassic. After an electron microprobe (EPMA) analysis, the composition of representative silicate from Xiaoyao granodiorite intrusion shows that the biotite is Mg-biotite. The whole-rock chemical compositions suggest that Xiaoyao granodiorite intrusion is of I-type, belonging to high-kalium calcium alkaline series granitoid, and the characters of the trace elements show that the rocks are enriched in LREE, and depleted of HREE, indicating the lower crust sourced magma with some mantle materials added, which experienced strong fractional crystallization during its evolution. The Xiaoyao intrusion granodiorite pluton is characterized by that of volcanic-arc granite (VAG).

Existingin schist and gneiss in Mengdong Group-Complex,the amphibolite belongs to Precambrian Formation in Laojunshan area of southeastern Yunnan, on which metamorphism and deformation superposed. The content of SiO₂ ranges from 47.0% to 50.4%. In the discrimination diagrams of Simonen,DF and A-K,it falls in the series of orthometamorphite derived from meta-basite rock. Its geochemical characters show that the total REE contents of amphibolite (w(ΣREE)=(214-267)×10^-6) exceed those of oceanic island basalt, while its distribution pattern is similar to that of oceanic island basalt in steep right-dipping with light REE enrichment. The spider diagram shows that it is enriched in Rb,Th,Ta,Nb,Ce and Sm,while depleted of Ba,Zr,Hf and Y, similar to the characteristics of the alkaline basalts within plate. The discrimination diagrams of Zr/TiO₂-Nb/Y, TiO₂-10MnO-10P₂O₅,La/10-Nb/8-Y/15,Th/Zr-Nb/Zr,and Th/Hf-Ta/Hf suggest that their protolith should be of alkaline basalt magma series in a continental rift environment. The microstructures of amphibole and plagioclase indicate that the microstructure is relatively free, with free dislocations and dislocation columns, occasionally dislocation rings or dislocation dipoles,which is in accordance with the average pressure and temperature of hornblende-plagioclase minerals of 0.88 GPa and 646℃ respectively, confirming that the highest metamorphic grade is of low amphibolite facies. According to the U-Pb dating of sphenes in plagiogneiss and metamorphic overgrowth zircon in Nanwenhe gneissic granite (230 Ma),the deformation conditions were related to the Indosinian tectono-thermal events, and during this period, the embryo of Laojunshan complex began to form.

To analyze the impact of particle composition on reinforcement of dredger fill under vacuum preloading from the aspect of meso-scale mechanism, we carried out a laboratory vacuum preloading model test on one group of samples from Binhai New Area in Tianjin using the particle flow method for simulation; then simulated six groups of samples with different grain size distributions under the same loading condition. The changes of drainage rate and deformation were analyzed. The results show that the two-dimensional particle flow method is effective for the simulation of laboratory vacuum preloading tests. Fine particles penetrated along the migration path with some detained along the way so that the penetration path became narrower and shorter. As for the newly-dredged fill with high clay content under the same loading condition, the initial drainage rate grew faster with the increase of clay content, and decayed faster with the increase of uneven coefficient; while the higher the silt content, the more uniform the porosity of soil at different position, especially, when the silt content was higher than the clay content, and the effecter of vacuum preloading.

In order to study on thermal damages of detective granite under temperature effect, an analysis on thermal stress of cracked granite was conducted through applying the theories of thermodynamics and damage mechanics. The critical stress formula of thermal damage of cracked granite was derived, further the influence of high temperature on the variation of the thermal elastic ratio of granite was analyzed, and then the thermal damage evolution equation of granite under temperature was established, finally the possible forms of the stress damage surface of granite under temperature were studied. A numerical simulation of the internal structure, crystal element damage, and stress variation of the Beishan defective granite under temperature was carried out. When the temperature rose to 60℃, a significant thermal damage occurred near the cracks of granite, and the damage was small far away from the cracks. When the temperature rose to 120℃, the shear failure characteristics of granite defects were obvious, the thermal damage near crack increased seriously, and the uninterrupted damages appeared obviously away from the defects. Under 120℃, a sudden change came out for the damage amount, the thermal stress, and the cumulative energy. Thereafter, with the increase of temperature to 200℃, the increment of damage is weak. The results show that there is a direct relationship between the damage and the temperature of Beishan granite with defects.

Under natural geological environment, a homogeneous geological unit is hardly existed. During the process of building a numerical model of groundwater system, it is difficult to accurately determine the hydrogeological parameters of each geological unit, which can truly depict an aquifer. The uncertain factors in groundwater modeling caused by the model uncertainties can affect the numerical model simulation process. Combing with the research of the hydrogeological parameter uncertainty and the development of geostatistics, the MODFLOW-Gslib software was developed based on the MODFLOW, which is the commonly used deterministic groundwater flow numerical software. Compared with the traditional numerical simulation method, this method of combining geostatistics with numerical simulation can simulate the parameter variability in heterogeneous aquifers. An example is given to quantitatively demonstrate the practicability of the software through choosing the hydraulic conductivity as the uncertain hydrogeological parameter to make a statistical analysis on the simulation results. It suggested that the parameters in the software are in accordance with the relevant characteristics of the uncertainty of the hydrogeological parameters. Compared with the MODFLOW simulation results, the software can describe the characteristics of hydrogeological parameter variability in an aquifer more accurately.

In order to study groundwater level (GL) rising impacts on suspended particle migration and deposition in porous media during artifical recharge of groundwater,three compared sand column experiments were conducted indoor using aritfical recharge water with suspended solids of 100 mg/L under three GL rising rates (0, 2, 4 cm/h). The results show that ground water level rise rate has little or no effect on the clogging position and the size of suspended solids at the clogging position. Most of the suspended solids deposit in the depth of 0 to 2 cm. While the clogging time characteristics varies observably with different GL rising rats. In the first 26 h, the infiltration rate under rising GL is smaller than that of constant, while it turned opposite after 26 h. The reason is that the total hydraulic head pressure difference decreases with GL rising for the early period, and when the clogging clayer developed to a certain degree (after 26 h), the seepage state of the non-blocking zone beneath clogging layer appears unsaturated, and infiltration capacity of the clogging layer controls the infiltration rate. Since the clogging rate of the main clogging layer of 0 to 2 cm is smaller under GL rising scenarios, the infiltration rate can still be maintained at a relative high value and occurrence of unsaturated infiltration state delayed as well.

The surface temperature of Changbai Mountain basalt area was interpreted by using Landsat TM5 multispectral and infrared data, and the potential geothermal fields were identified by using discrimination analysis on the surface temperature, hot springs and geothermal well distribution, gravity, and magnetic fields. The results show that the surface temperature abnormal areas are mainly distributed around the Tianchi volcano area on Changbai Mountain and the three Mesozoic sedimentary basins (Fusong, Songjiang, and Changbai basins). The proportion of abnormal pixel in surface temperature is 2.993%. The potential geothermal fields in the study area are divided into four regions, including the area around Changbai Mountain Tianchi volcano, Songjianghe-Fusong County, Erdaobaihe-Songjiang Country (Fusong and Songjiang basins), and Xianrenqiao-Changbai County-Shisidaogou(Changbai basin). The probability of potential geothermal resources is greater than 0.9, and the maximum value is 1.0 in Changbai Mountain Tianchi volcano region. The study provides a new approach for potential geothermal field identification.

Nitrogen is essential for plant growth and development; therefore, it is of great significance to study the spatial distribution characteristics of nitrogen in soil supplied by recycled water. Soil tolal nitrogen(TN) is complex for its distribution and mechanism under the influence of hydrological conditions to a urban wetland. Taking Beijing Mencheng Lake Wetland Park as the study area, where the reclaimed water is the main water supply, we studied the spatial distribution characteristics of the total soil TN content using ArcGIS and Geo-statistics. The results show that the total soil TN content is high in the study area with a large range coefficient of variation of 47.35%. Among different plant communities in the area, the total soil TN content in typha community is the highest. The total phosphorus is closely correlated with TN (r=0.79,P<0.01); and soil organic matter is also obviously positively correlated with TN (r=0.58, P<0.05). Among the climate factors, temperature and humidity affect the distribution of total soil TN significantly in the study area. In addition, the soil TN measured at the reclaimed water outlet is higher than that in the other areas. With the increase of distance away from the outlet, the TN declines in general, and becomes stable. Our study indicates that vegetation plays an important role in adjusting soil nitrogen in the wetland treated with recycled water.

As an effective and efficient electromagnetic method, magnetometric resistivity method has been extensively used worldwide; however, it is unfamiliar in China. Therefore, this paper tries to introduce the fundamentals of this technology on the three aspects, i.e. data collection and analysis, forward modeling, and inversion through case studies, in order to outline the potential development in China. In this review, we indicate that:1) most of the time, gradient array is used for surface MMR data collection, yet the survey layout in other electromagnetic method can be adapted; 2) from view point of electrostatic theory, absolute conductivity cannot be obtained by the magnetometric resistivity method; however, if we collect data in frequency domain, the problem may be solved; 3) deep resolution of surface MMR data need to be, and can be improved through multi-source and multi-component 3D inversion; 4) in China, MMR could be extended to borehole exploration, marine exploration, and applied to the scope of environment, and engineering.

Random noise is one of the serious problems encountered during the GPR data processing. It directly influences the accuracy and reliability of the processing results. In order to remove the random noise effectively and retain the useful information, the authors propose a random noise suppression method in GPR data by using Shearlet transform. As a non-adaptive geometric-analysis method with multi-directions and multi-scales, Shearlet transform can be used to approximately represent the high-dimensional curves with singular points. In Shearlet domain, GPR data appear more sparsely. Through the threshold de-noising method, random noises can be suppressed effectively; so that the signal to noise ratio (SNR) is improved by 4 dB, and the useful information is retained to the maximum extent. The effectivity and accuracy of the Shearlet-transform threshold de-noising method are validated by the theoretical and practical data.

The traditional study of surface-related multiple elimination (SRME) is based on two-dimensional algorithm to confine the contribution of multiple waves, which is too constrained to deal with a complex geological structure. The 3D SRME algorithm can hardly be promoted and applied because of its clumsy algorithm and harsh demand of data. The multiple prediction with 3D sparse inversion takes advantage of Cauchy probability density function totransform the multiple waves' energy contribution gathers to model spacetoreconstruct the event energy vertex-Fresnel zone so as to calculate and predict multiple waves' energy effectively and accurately. The Curvelet match method is used to remove multiples from seismic data withretainingmany more directions and scales more effectively compared to the traditional least square matching phase subtraction. In comparison withthe result of 2D SRME, the effectiveness of this method is verified through establishing a 3D inclined layer velocity model and testingit on simulated 3d seismic data.

An absorbing boundary condition is needed to absorb the artificial boundary reflections in a numerical simulation of seismic wave. We presented a perfectly matched layer (PML) absorbing boundary condition for a second-order elastic wave equation in a curvilinear coordinate system. Similar to the PML in a Cartesian coordinate system, the PML absorbing boundary condition in a curvilinear coordinate system was formulated in frequency domain, which was obtained by the corresponding complex coordinate transformation. To transform the condition into time domain will result in complex convolutions in the perfectly matched layer. To avoid these convolutions, we introduced 4 intermediate variables. Furthermore, to simplify the free boundary condition, we adopted the orthogonal body-fitted grid for mesh generation of a rugged topography model. The numerical results show that the proposed method can absorb artificial boundary reflections effectively.

Weathering cores (commonly known as "boulders") from the residues of orbicular or blocky granite are widely developed in southern coastal cities in China. "Boulder" often leads to stuck and damage of shield cutter head,and may cause problems such as surface uplift. Detecting "boulder" before shield construction for pretreatment is a challenge for a metro engineering survey. The different characteristics of seismic wave impedance of boulders and soil surrounded provide a theoretical basis for the application of seismic imaging method in a boulder exploration. In this study,we introduced the basic working principle and methods of three-dimensional seismic imaging; then we established a three-dimensional finite element model which contains the boulder to simulate seismic imaging in three-dimensional stratum formation and study the regulation of waveform cross-sectional view at different position of survey lines. The result shows that when the survey line lies in the boulder's projection area, the obvious reflection wave and diffracted wave appear. The existence of boulder can be thereby clearly detected,and the plane form and burial depth of the boulder can be determined after data processing. Finally, we applied this method to Xiamen subway shield zone. When a wave appeared abnormal, reflecting frequency became obviously low, amplitude got larger, oscillation and co-phasal axes similar to a short arc came into being at the same time, we drew the conclusion for the existence of an underground boulder. We confirmed the feasibility of the method through comparing the exploration results to the borehole data. This three-dimensional imaging method improves the visualization degree of the detection results,and provides a reference for geotechnical detection in a similar area.

For further studying seismic activity of Qianguo in Jilin Province,we collected 405 seismic events recorded by 17 permanent and temporary stations from October 2013 to February 2015, and total 2 218 high-quality P wave arrival times and 2 166 high-quality S wave arrival times. We used double-difference tomography method to invert the upper crust P and S wave velocity structure in Qianguo region (in the region of epicentral distance range of 0-200 km). The tomography results show that the velocity structure beneath thestudy area exhibits an obvious feature of stratification, the P wave velocity varies from 5.8 km/s to 7.2 km/s,and the S wave velocity is from 3.4 km/s to 4.0 km/s, with a small change on the v_P/v_S ratio. A low velocity zone beneath thestudy area is found with a trend of NE direction and a nearly vertical steep dip angle, and it extends as deep as 15 km. The earthquake cluster is located in the low P wave and low S wave velocity region corresponding to a low v_P/v_S ratio;so we suggest that the tectonic intensity of this region is weak, and prone toearthquake under the influence of the stress field derived from the subduction of Western Pacific slab.

It is difficult to represent the multi-scale structure feature of rocks by using a single resolution digital core model. Through taking a sandstone sample, by means of core multi-resolution CT imaging,the accurate matching of core images with different resolutions is realized by the feature based image registration method. The multi-scale and -component digital core model is constructed along with the segmentation of pores and minerals in the registered images based on image fusion. The results show that the multi-scale and -component digital core model could represent the cross scale pore structures; and the pore distribution agrees with the results from NMR. The mineral contents of digital core are more consistent with the results from XRD than that from Qemscan. The multi-scale and -component digital core model factually restores the structure features of all rock components.