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The pore structure and movable fluid characteristics of tight conglomerate reservoirs are complex, which are greatly different from conventional reservoirs. The depositional mechanism is the fundamental factor controlling the physical properties of conglomerate reservoirs. However, there is a lack of systematic research on the pore structure and movable fluid characteristics of conglomerate reservoirs with typical sedimentary facies. This paper investigates the pore structure and movable fluid characteristics of conglomerate of different sedimentary facies based on various experiments. Casting thin sections, X-ray diffraction, scanning electron microscopy, high-pressure mercury injection, and nuclear magnetic resonance experiments were conducted on 32 conglomerates samples from the Mahu Sag, Junggar Basin, China. The quality classification method of tight conglomerate reservoirs is established. The results show that the conglomerate can be divided into three sedimentary facies; traction flow conglomerate (TFC) and pebbled sandstone (PSS) mainly develop intergranular pores and dissolved pores; and the pore diameter curves are mainly a double peak, single peak, and flat peak. Gravity flow conglomerate (GFC) mainly develops dissolved pores and interstitial micropores, and the pore diameter curve is mainly a single peak. PSS includes pebbled gritty sandstone (P(G)SS) and pebbled fine sandstone (P(F)SS). TFC and P(G)SS are favorable class I reservoirs, while GFC and P(F)SS are nonfavorable class II reservoirs. A new parameter, the ratio of the major axis to the minor axis of the pore outer ellipse (axial ratio), is proposed to quantitatively describe the compaction effect. The average axial ratios of the three lithofacies are 3.04, 3.98, and 8.78, respectively, indicating that the compaction is intensified and the pore structure becomes worse. By analyzing the correlation between pore structure parameters and permeability, it is found that the main controlling factors of permeability of GFC and TFC are sorting and connectivity, respectively, and the main flow radius is the most suitable parameter to describe permeability. A linear spectral decomposition method was used to establish a new quantitative calculation method of movable fluid saturation for different types of pores, and the results show that the movable fluid saturation of intergranular pores is the highest (average: 65.43%), and the movable fluid saturation of TFC and P(G)SS with more intergranular pores is the highest. Movable fluid saturation is inversely proportional to the content of I/S and the compaction rate and positively proportional to the content of quartz and feldspar and the cementation rate. The fluid mobility of water-wet samples is weaker. The research results provide theoretical support for the identification of favorable reservoirs and the cognition of a development mechanism.

The rock joint roughness greatly affects the mechanical behaviors and permeability characteristics of rock mass. To accurately and effectively estimate the roughness of rock joints, an appropriate sampling interval is required to be specified during the point cloud collection using laser scanning systems and the roughness coefficient calculation. Firstly, seventeen point clouds of rock joints with sampling size ranging from 60×60 to 2000×2000 mm was collected using a terrestrial laser scanner in the field to investigate the effect of sampling size on the selection of the appropriate sampling interval. Then, a portable laser scanner was employed to acquire the dense point clouds of thirteen small-scale rock joint specimens, which have various roughness levels, to assess the influence of roughness level on the appropriate sampling interval. Furthermore, fitting analyses were performed to establish relationships between the appropriate sampling interval vs. sampling size and the appropriate sampling interval vs. roughness level, respectively. The results show that the curves of sampling interval vs. roughness coefficient followed a power distribution, and the inflection point with the maximum curvature could be regarded as the appropriate sampling interval; the appropriate sampling interval increased with the sampling size, while a negative correlation between the appropriate sampling interval and roughness level was observed. To facilitate the application of findings into practical engineering, a simplified workflow was provided to determine the appropriate sampling interval: 0.015×sampling size and 0.03×sampling size were recommended to be considered as appropriate sampling intervals for the rock joints with high-level and low-level roughness, respectively.

Concentration of elements or element groups in a geological body is the result of multiple stages of rock-forming and ore-forming geological processes. An ore-forming element group can be identified by PCA (principal component analysis) and be separated into two components using BEMD (bi-dimensional empirical mode decomposition): (1) a high background component which represents the ore-forming background developed in rocks through various geological processes favorable for mineralization (i.e. magmatism, sedimentation and/or metamorphism); (2) the anomaly component which reflects the ore-forming anomaly that is overprinted on the high background component developed during mineralization. Anomaly components are used to identify ore-finding targets more effectively than ore-forming element groups. Three steps of data analytical procedures are described in this paper; firstly, the application of PCA to establish the ore-forming element group; secondly, using BEMD on the ore-forming element group to identify the anomaly components created by different types of mineralization processes; and finally, identifying ore-finding targets based on the anomaly components. This method is applied to the Tengchong tin-polymetallic belt to delineate ore-finding targets, where four targets for Sn (W) and three targets for Pb-Zn-Ag-Fe polymetallic mineralization are identified and defined as new areas for further prospecting. It is shown that BEMD combined with PCA can be applied not only in extracting the anomaly component for delineating the ore-finding target, but also in extracting the residual component for identifying its high background zone favorable for mineralization from its ore-forming element group. Keywords: Bi-dimensional empirical mode decomposition (BEMD), Principal component analysis (PCA), Anomaly components, Ore-forming element groups, Sn (W) and Pb-Zn-Ag-Fe polymetallic deposits, Tengchong tin-polymetallic belt

There is an increasing trend towards using numerical wave simulations for the design of offshore structures, especially for the stochastic prediction of nonlinear wave loads like those related to air-gap and wave impact. Unlike experimental facilities, where the complex nonlinear physics of wave propagation is simply enforced by the laws of nature, numerical wave tanks (NWTs) rely on assumptions and simplifications to solve the propagation equations in a reasonable amount of time. It is therefore important to verify the quality of the waves generated by NWTs in terms of realistic physical properties. As part of the effort to develop reliable numerical wave modeling practices in the framework of the “Reproducible Offshore CFD JIP”, qualification criteria are formulated for the wave solutions generated from either potential-flow based or CFD-based codes. The criteria have been developed based on experiences from physical wave tank tests and theoretical/numerical studies. They are being evaluated using results from several numerical models and available benchmark data. This paper presents the proposed qualification criteria and on-going evaluation efforts by comparing results from different codes.

Landslide is one of the most common geological hazards, which causes a large number of property damage and loss of life in China every year. This case study was a 330-kV transmission line project located in Longnan City, Gansu Province, China, which is known as an area prone to landslides. A hybrid model of fractal theory-information value-random forests algorithm (FT-IV-RF) was proposed to evaluate the landslide susceptibility. First, sixteen landslide conditioning factors and pre-existing landslide events were selected as the initial evaluation indexes of landslide susceptibility from four datasets (geology, topography, climate and environment, and landslide inventory). Second, Pearson coefficient and sensitivity analyses were conducted to extract ten landslide conditioning factors with small correlation and large contribution to landslide occurrence from sixteen factors. Third, the weight of each class for a given factor were determined by using a combination of fractal theory and information value algorithms, which was regarded as one of input parameters and used to select the training samples in the random forest model. Four, k-means clustering was performed to classify the landslide susceptibility indices, which were predicted using the random forest model, into five levels to produce the landslide susceptibility map of the study area. Furthermore, the proposed model of FT-IV-RF model was validated by comparing with results obtained using information value (IV), back-propagation neural network (BPNN), and fuzzy logic (FL) models. Good agreements on the susceptibility estimation were observed among four models, and the hybrid model had the largest area under the curve (AUC) value of 0.996, indicating a good performance of the proposed hybrid model.

Over the last decade, Fengcheng oil field rich in heavy oil geological reserves has had a broad prospect of exploration. The reservoirs are mainly composed of high porosity, high permeability sandstone and conglomerate in study area. The reservoir characteristics led to poor fluid and gas injection causing ground surface deformation with the injection of gas and fluid and threatened the safety of nearby construction facilities. Interferometric Synthetic Aperture Radar (InSAR) technology has been used to identify ground surface deformation with high precision, which is widely used in various fields. This paper adopted Small Baseline Subset InSAR (SBAS-InSAR) method to monitor oil field for the period of February 2007 to September 2010. In this study, the Fengcheng oil field in Xinjiang served as an example; we measured subsurface fluid and gas injection-induced ground surface deformation by SBAS-InSAR technique and investigated the causes of observed deformation. The results showed significant uplift over Fengcheng oil field and testified the feasibility of SBAS-InSAR method. The Phased Arrary L-band Synthetic Aperture Radar (PALSAR) datasets outcome revealed ground surface maximum cumulative uplift for 4 years was 40 cm in the line of sight (LOS) direction, and annual average deformation rates were ranging from − 80 to 120 mm/year. Further, the time series analysis based on monitoring results found that the causes of ground surface uplift were related to the increase in pore pressure under the reservoir, and the surface deformation area corresponded to the production well position of study area. Therefore, InSAR technique is an essential tool for the ground surface deformation monitoring due to fluid and gas injection in heavy oil field, ensuring the safety of personnel and property.

An approach was proposed to automatically measure the discontinuity geometric properties from a point cloud acquired using Light Detection and Ranging (LiDAR). The procedure primarily includes the following features: (Assali et al., 2016) Grid data from the point cloud was created to enhance computational efficiency for data processing and retrieval; (Barton & Choubey, 1977) A modified region growing (MRG) algorithm, which is characterized by more efficient grow criterion, was used to recognize discontinuities from the point cloud; (Cao et al., 2017) Four geometric properties from identified discontinuities were calculated based on analytic geometry; (Chen et al., 2016) Influence of threshold T on the identified results was investigated through sensitivity analysis, and threshold T was suggested to be less than the minimum normal difference among all joints and larger than 0°. Two cases (regular polyhedrons and a tunnel in the Rumei hydropower station) were taken as case studies to validate the developed approach, and calculation results have good agreement with real situations.

Power transmission towers have a strong backscattering property in SAR images. In high-resolution SAR images, the target property of UHV towers is reflected as a series of bright spots and form into bright lines that are wide in range and narrow in azimuth. The power transmission towers can be precisely extracted from high-resolution SAR images by their geometric structures, spatial topological relations, texture features and other information. In this paper, we put forward the long time series interferometry for deformation monitoring of UHV power transmission towers in goafs, and an experiment on the deformation monitoring of UHV power transmission towers in the study area is carried out. The result indicates there are two clear subsidence centers in the study area and the ground subsidence is expected to get worse year by year as new infrastructures are constructed in the study area.

Incremental vertical ground movements due to coal mining can increase landslide susceptibility greatly in a short time and have thus triggered a large number of geological disasters, especially in the Karst Region, where a lot of steep slopes are on fractured rocks. Therefore, the landslide susceptibility maps (LSM) in Karst Region should be updated regularly. This paper presents an efficient methodology to update and refine LSM by using Persistent Scatterer Interferometry (PSI) data directly. First, an original LSM was produced by using a support vector machine (SVM) algorithm, and the distribution of coal mining was considered a crucial factor to generate the LSM. Then, the Permanent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR) technique was implemented to retrieve displacement time-series. Finally, the landslide displacement map, produced by the PSInSAR analysis, was projected to the direction of the steepest slope and resampled to the same cell in the LSM, to update the original LSM. This methodology is illustrated with the case study of Bijie in the Karst Region of Southwest China, wherein the ascending RADARSAT-2 and descending Sentinel-1 datasets are processed for the period of 2017–2019. The results show that the susceptibility degree increased in 56.41 km2 of the study area, and 80 percent of the increased susceptibility degree was caused by coal mining. The comparison between original and refined LSM in two specific areas revealed that the proposed method can produce more-reliable landslide susceptibility maps in areas of intense mining activities in the Karst Region.

Deformation monitoring is a powerful tool to understand the formation mechanism of earth fissure hazards, enabling the engineering and planning efforts to be more effective. To assess the evolution characteristics of the Yangshuli earth fissure hazard more completely, terrestrial laser scanning (TLS), a remote sensing technique which is regarded as one of the most promising surveying technologies in geohazard monitoring, was employed to detect the changes to ground surfaces and buildings in small- and large-scales, respectively. Time-series of high-density point clouds were collected through 5 sequential scans from 2014 to 2017 and then pre-processing was performed to filter the noise data of point clouds. A tiny deformation was observed on both the scarp and the walls, based on the local displacement analysis. The relative height differences between the two sides of the scarp increase slowly from 0.169 m to 0.178 m, while no obvious inclining (the maximum tilt reaches just to 0.0023) happens on the two walls, based on tilt measurement. Meanwhile, global displacement analysis indicates that the overall settlement slowly increases for the ground surface, but the regions in the left side of scarp are characterized by a relatively larger vertical displacement than the right. Furthermore, the comparisons of monitoring results on the same measuring line are discussed in this study and TLS monitoring results have an acceptable consistency with the global positioning system (GPS) measurements. The case study shows that the TLS technique can provide an adequate solution in deformation monitoring of earth fissure hazards, with high effectiveness and applicability.

Heavy rainfall and reservoir drawdown rate are primary factors when evaluating landslide stability. This paper intends to ensure the feasibility of increasing reservoir drawdown rate before flood season influenced by those two factors in the Three Gorges Reservoir (TGR) area. At first, a heavy rainfall was calculated by Pearson type ? distribution (PE3) using rainfall data of 20 counties from 1960 to 2010. Based on the reservoir operation, annual rainfall data was divided into four groups and calculated separately. The parameters of PE3 were estimated by curve fitting method and validated by Kolmogorov-Smirnov test. Then a reservoir drawdown model was proposed considering the actual regulation of reservoir. At last, a seepage-slope analysis was carried out using extreme rainfall and reservoir drawdown model on Sifangbai landslide. The extreme rainfall results show that the extreme rainfall during flood season was 2.5, 1.4 and 2.2 times greater than that in other three parts. Stability analysis showed that the landslide stability was mainly influenced by reservoir drawdown. Total time and elevation in rapid drawdown model would reduce with the increase of reservoir drawdown rate. With extreme rainfall data and reservoir drawdown model provided in this paper, similar partially submerged landslides in the TGR can be evaluated before increasing reservoir drawdown rate.

A coupled floating body-mooring line model is developed by combining a boundary element model for a two-dimensional floating body and a catenary mooring line model. The boundary element model is formulated in the time domain by a continuous Rankine source, and a reflection potential is introduced to account for the wave reflection due to sloping seabed. This newly developed model is validated by comparisons against available data. Then, dynamic response analyses are performed for the moored body in various seabed conditions. Compared with a flat seabed, a sloping seabed causes unsymmetrical mooring line configuration and generates noticeable effects in the motion responses of the floating body.

Landslides cause damages to land and infrastructure and pose serious threat to human survival. To prepare a landslide susceptibility map of the region in Longnan, City Gansu Province, with a 330-kV transmission line, 10 parameters were selected by correlation analysis and sensitivity analysis from initial 18 and five different methods were used, including analytical hierarchy process (AHP), information value (IV), fractal theory (FT), back propagation neural network (BPNN), support vector machine (SVM). The susceptibility maps were validated through receiver operating characteristic (ROC) and cumulative landslides percentage curves based on 77 existing landslide events. The results indicate that BPNN and SVM model are most accurate, time-saving and easily implemented. All of the five methods accurately predict the spatial distribution of landslides and can be well applied to landslide susceptibility mapping. What needs to be emphasized is that the machine learning methods have the advantages of high efficiency, accurate prediction, time-saving, convenient implementation, which are relatively new and better evaluation models of susceptibility.

The universal features of the gas wells in Sulige gas field are low pressure, low production rate, and the liquid-carrying capabilities of the wells that are poor. Accompanied with the gas well entering the process of middle and late life span, the pressure of the well bottom gets low and the liquid-carrying capability of the well becomes poorer. Liquid-carrying capability of gas well could be effectively improved by using velocity string. However, the former effect evaluations of drainage gas recovery by velocity string are confined to individual well. On the basis of all the gas wells which use the technology of velocity string in Sulige gas field, classification evaluations are made in this paper according to the pretest gas production rate. The technological principle of drainage gas recovery by velocity string is analyzed, and the model of critical liquid-carrying which fits for Sulige gas field is derived. Then, coiled tubing of φ38.1 mm is optimally selected which serves as velocity string according to this model. Finally, the scope of applications of drainage gas recovery by velocity string in Sulige gas field is obtained and the new application fields of this technology are proposed.

In rough sea conditions, Semi-submersible platform often suffers from extreme wave impact loads, which can result in structural damage. It is important to predict the wave impact loads on Semi-submersible platform. A CFD method, based on a fixed regular Cartesian grid system, has been developed by the authors for wave impact loads on semi-submersible platform (Liao et al., 2017). However, time consuming is still the bottleneck of CFD method for industry application. In this study, a coupled potential-viscous flow method is developed for improving computational efficiency. In the present method, our CFD in-house code is coupled with MrNWB dynamic libraries using the Euler Overlay Method (EOM) (Baquet et al., 2017). Comparison of the computational accuracy and efficiency between our original CFD in-house code and the present coupled method will be discussed in detail, and benchmark model test will also be used to validate the present coupled method in wave impact simulation.

The transmission distance of transmission lines is long, the line affected by the diversity of climate and topography of the corridors of transmission lines, differences in regional geological structure conditions, variability of rock and soil types, and the complexity of groundwater. Under the influence of extreme weather conditions (ice-covered, strong wind, etc.) and sudden geological disasters (such as mudslides, flash floods, earthquakes, etc.), catastrophic damage and basic deformation problems of the tower foundations are prone, and even tower collapse accidents occur in severe cases, which affect the safe operation of transmission lines. Monitoring the deformation of power transmission towers and surrounding grounds, it is critical to ensuring the normal operation of transmission lines by assessing and controlling potential risks in advance. In this paper, using ALOS-2 PALSAR radar satellite data, differential interferometry was used to monitor surface deformation near the Sichuan Jinsu line transmission channel. The analysis found that a significant landslide hazard was found near the transmission channel tower in Yibin-Zhaotong section of Jinsu, Sichuan Province, the cumulative deformation reaches 9cm. The results of this paper can provide new monitoring means for safety monitoring of transmission towers.

The Gejiu tin polymetallic ore deposit, located at the westernmost end of the Cathaysia Block, is one of the largest tin polymetallic ore deposits in the world. It is associated with a magmatic-hydrothermal ore-forming system triggered by the deeply buried geological structures and concealed granites. A singular value decomposition (SVD) program on a MATLAB platform was effectively used to extract deeply buried geological information reflecting deep-seated geological structures and the concealed granites by decomposing gravity signals within the Gejiu tin polymetallic ore field. Firstly, the gravity signals were decomposed into a few components with different eigenvalues using a singular value decomposition (SVD) approach. Secondly, the thresholds between the eigenvalues of gravity components reflecting deeply and shallowly buried ore-controlling geological structures and/or geological bodies were established by a multifractal method. Finally, the images of gravity components reflecting deeply and shallowly buried ore-controlling geological structures and/or geological bodies were reconstituted. This yielded two layers of significant two dimensional singular value gravity component images that indicate deeply and shallowly buried ore-controlling geological structures and/or geological bodies, respectively. The deep layer of gravity component image reveals a negative gravity anomaly (I) which indicates that the granites exposed in the west ore field, bounded by the Gejiu Fault, may be extended to the east ore field at depth, forming concealed granites (Fig. 4). The shallow layer of gravity component image reveals a structural framework created by two groups of NW-trending and three groups of NE-trending positive gravity component images defining two negative gravity anomalies (I and II), which may reflect existence of the exposed granites in the western ore field (I) and the concealed granites in the eastern ore field (II) (Figs. 5 and 6). Almost all tin polymetallic deposits are located within the negative gravity anomalies (Figs. 4 and 5). This approach, combined with the identification of geochemical anomalies plays an important role in the discovery of deeply buried tin polymetallic ore deposits, including the 0.78 million tons of tin reserves over the last ten years.

In rough sea conditions, semi-submersible platform often suffers from extreme wave impact loads, which can result in structural damage. It is important to predict the wave impact loads on semi-submersible platform. Therefore, the purpose of this study is to investigate the wave impact loads on semi-submersible platform with numerical methods. A numerical method, based on a fixed regular Cartesian grid system, has been developed by the authors. In the method, the FDM (Finite Difference Method) is applied for solving flow field, and the THINC/SW (Tangent of Hyperbola for INterface Capturing with Slope Weighting) model, which is kind of VOF (Volume-of-Fluid) model, is adopted to capture the free surface. Some selected model test cases, form Exwave JIP project, will be used to validate the present numerical method and to analyze the wave impact loads on semi-submersible platform.

A bidimensional empirical mode decomposition (BEMD) program on a MATLAB platform was effectively used to handle gravity signals for the Tongshi gold field. This yielded a two-dimensional intrinsic mode function (IMF"3) image that meticulously depicts the spatial distribution relationship between various gold deposits and the different geological units of the gold field. By combining the IMF"3 image with geological features, the Tongshi gold field can be divided into three geological units. Unit I is made up of both Archean greenstone and Cambrian-Ordovician carbonate rocks and is defined as a concealed basement that exhibits weak negative and positive gravity anomalies. Unit II is defined as a Mesozoic volcanic sediment basin consisting of Jurassic and Cretaceous volcanic-sedimentary rocks, which developed on the concealed basement and exhibits an obvious negative gravity anomaly. Unit III, located on the concealed basement on the SW side of the Mesozoic volcanic-sedimentary basin, can be subdivided into subunits IIIa and IIIb. The former, with a negative circular gravity anomaly, indicates that the Tongshi complex consists of both Yanshan diorite-porphyrite and syenite-porphyry. Unit IIIb, with a positive ring gravity anomaly distributed around a negative circular gravity anomaly, indicates a possible contact metasomatic mineralization zone around the Tongshi complex. Almost all types of gold deposits are located within this contact metasomatic mineralization zone and thus the zone is a prospective area for gold deposits.

Platinum has been one of the highly needed mineral resources in China. The geochemical exploration at two survey scales was applied in telescoping ore targets for the first time in Eastern Yunnan Pt geochemical province that was delineated using Pt data from flood plain sediments with extra-low sampling density. Our study was based on the delineations and assessments of both regional and local Pt anomalies using the Pt data by analyzing with C-OES the composite samples with two sampling densities. The composite samples were obtained by recomposing at two sampling densities the original stream sediment samples collected by the National Geochemical Mapping Project. Semi-variograms were used to quantitatively describe the variability of Pt anomalies and further analyze the factors controlling the variability. Pt resource potentials of both the regional Pt anomalies and the local Pt anomalies in the study area were estimated based on the geochemical block methods, respectively. It comes to the conclusions as follows. (1) From the regional to local Pt anomaly, the factors controlling their variability from the deep seated faults-basalts turn into the basalts-branch faults, which suggest that Semi-variograms could identify the geological factors controlling the variability of the Pt anomalies identified by the Pt data from the stream sediments with different sampling densities. (2) There exist two types of Pt anomalies in the study area. One is those displaying at sampling densities, and its average Pt concentration significantly increases with sampling density increasing. The other is getting weaker and/or disappears with sampling density increasing. This shows that TOTGEMS could gradually eliminate non-ore anomalies and keep ore anomalies. (3) The average Pt concentration of the local Pt anomaly blocks delineated using Pt data from stream sediments with sampling density of one composite per 16 km2 is twice as much as that of the regional Pt anomaly blocks delineated using Pt data from stream sediments with sampling density of one composite per 64 km2. The Pt resource amount of the local Pt anomaly blocks is 60% of the regional anomaly blocks, but the area of the former is just 35% of the latter, which suggests that the Pt resource amount is mainly concentrated in its local anomalies, and that TOTGEMS has a good exploration function that efficiently approaches ore targets.

The principle of Bi-dimensional empirical mode decomposition(BEMD)is elucidated in this paper. A BEMD program on MATLAB platform was compiled and effectively used to handle regional and local gravity signals for the western Shandong uplift block. This yielded two significant two-dimensional intrinsic mode function (BIMFs) images: regional intrinsic mode function (RIMF) and local intrinsic mode function (LIMF). The former depicts spatial distribution relationships between regional mantle swells and igneous rock bodies associated with gold deposits within Shandong Uplift Block; and the latter does the spatial distribution relationships between the various types of gold deposits and the different geological units in Tongshi gold field within Shandong Uplift Block, which provide a reliable evidence for searching for new gold deposits in this area. The BEMD method is suitable not only for analysis of gravity data, but also might be extended for analysis of the scattered data like magnetic data and exploration geochemical data.

Exploration data from geophysics and geochemistry have anisotropic features because anisotropy is an intrinsic property of geological bodies, including ore bodies. Lovejoy et al developed Generalized Scale Invariance (GSI) to account scaling anisotropy. The Scale Invariant Generator technique (SIG) is used for decomposing the gravitational data of different frequencies and extracting ore-forming anomalies from them in frequency domain combining with the principle of spectral analysis. The anisotropy of the Tongshi gold field and the spatial relationship of the Tongshi complex and gold deposits will be studied. This will provide valuable information for predicting the gold mineralization at depth.

The Green-Naghdi (GN) theory is used here to simulate two-dimensional (2D) underwater landslide-induce tsunamis. Finite difference method is used to solve the GN equations. GN theory has different levels. There are GN-1, GN-2, ⋯, GN-K theory in GN theory. When K goes up, the GN equations will be more complicated, and the results will be more accurate. For the case simulated here, results of GN-5 theory are better than results of GN-3 theory. GN-7 results are almost the same as GN-5 results. That means GN-5 results are the converged results from GN theory. GN-5results agree well with other's experimental results.