The models of sequence stratigraphy and depositional architecture of the rift lacutrine basin in response to the background of extension and strike-slip tectonic mechanisms

Zhao Chunchen1, Liu Hao1* and Zhou Xinhuai2

Huanghekou depression of Bohai Bay basin is in a special tectonic environment. Due to the existing of the Tan-Lu fault zone the tectonic mechanism of extension and strike slip affected the whole strata profoundly, especially the sequence and depositional models of Palaeogene. This phenomenon led to huge differences of the sequence statigraphy and depositional architecture. Thus this study aims in using seismic datas, complemented by well logs and cores to analyze thoroughly the sequence stratigraphy and depositional architecture of the Huanghekou depression and their models in response to the background of extension and strike-slip tectonic mechanisms in this rift lacustrine basin. Palaeogene is divided into 9 composite sequences on the basis of unconformities on depression margins and correlative conformities in the depression center. Every sequence is composed of a regional depositional cycle from transgression with an onlapping lacustrine expanding systems tract (EST) to regression with a prograding highstand systems tract (HST). There are five depositional systems in the Huanghekou depression including fan delta, braid river delta, meandering river delta, the lacustrine depositional system and sublacustrine fan. One of two depositional models is that fan delta and sublacustrine fan were developed in north steep slope. The middle was similar with the north. In south gentle slope depositional systems were braided river deltas. The other is that the depositional system was mainly developed by meandering river delta in the north. In the middle the large-area beach bar can be found and the large scales of braided river deltas were developed continuously in south gentle slope. Finally through the analysis of the physical characters and the sandstone reservoir of the different micro-facies, we know that under the extensional model the best sandstone reservoir distributed in mouth bar and far bar of braided river delta in south gentle slope belt. Under the duplex tectonic mechanisms, the best sandstone reservoir can be seen in beach bar of shore and shallow lacustrine deposit¬ional system.

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Numerical Analysis of DOT Shield 45° crossing the Masonry Structure Buildings

Wei Gang

Considering the intersection of building - soil – tunnel, 3D MIDAS / GTS software is used to simulate the conditions of DOT shield tunnel 45° crossing the raft foundation under masonry structure buildings. Additional subsidence and force of the building caused by tunnel construction are studied and the impact of the horizontal position change between tunnels and buildings is considered. The analysis results show that as the DOT shield machine crosses the building, the building would generate uneven horizontal subsidence, it would tilt more in the back-end than the front-end, building subsidence would be stable and slightly rebound after the shield entirely passed through the building; longitudinal differential subsidence would first increase and then decrease, at last the buildings are permanently distorted. With the increase of horizontal distance between the tunnel axis and buildings axis, the building presents a trend dumping to one side of the tunnel, the local inclination of the foundation first increased and then decreased, the maximum shear strain and the first principal stress roughly showed the same changing trend which increased first and then decreased linearly.

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RSpatial and Temporal Distribution Characteristics of Microseismic Events in Deep Mining

Wang Chun-lai

The microseismic monitoring is an effective means for the microseismic events which are induced by instability of ruptured rock mass in deep mining. Based on the complex geological condition of lead and zinc mine in Southwest China, a digital 24-channel microseismic monitoring system was established to monitor the microseismic events in deep mining. In the microseismic events monitoring data, the spatial and temporal distribution characteristics of microseismic events were analyzed by using system clustering analysis method. Results show that the microseismic events have the distributions characteristics from the same time different spatial domain and the same spatial different time domain. In spatial domain, the microseismic events were characterized in cluster, intermittency and tapability. In time domain, the microseismic events were characterized in stable, supervention and intermittency. It was concluded that the close relationship exists between the distribution characteristics of active microseismic events and deep mining.

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Research on Web-Based Dynamic Thematic Mapping Services Technologies

Guo Lixia1, 2* and YanYunxuan1

With the help of Geographic Information System (GIS), thematic maps have come into wide use and played importand roles in the field of natural disaster applications, such as flood, forest fire and draught, so as to assist the decision makers to better understand the spatial phenomena and to take effective measures. Recently, Web Map Service (WMS) has become closely related with people life regarding geographic information. However, on the one hand, so far as symbol rendering and vector expression are concerned, current specifications provided by OGC (Open Geospatial Consortium), such as Styled Layer Descriptor (SLD), can not meet the demands of thematic mapping; on the other hand, present WMS is just simply publishing predefined map on internet, not for the dynamic thematic mapping with material provided by amateur user, neither familiar with geographic information, nor internet knowledge. In view of existing problems in thematic mapping in the web environment, we propose the concept of “Web Thematic Mapping Service” and develop its dynamic mapping model and architecture, aiming at creating customizable thematic map dynamically in way of user interaction on the client side. Additionally, taking into account the efficiency, we also focus on the key technologies in web mapping such as fast map publishing of spatial data and automatic linking technology of spatial data with attribute data. Finally, we dynamicly make the thematic map of the Huaihe River flood disaster, based on the theory and architecture.

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Research on Connectivity of Deep Ore-lodes of Borehole based on Digital Borehole Camera

Zengqiang Han1*, Chuanying Wang1, Shaobo Liu1 and Hengyin Zhu2

Ore-lodes in deep mineral exploration borehole can be obtained by digital borehole camera technology. The conditional restriction of connectivity of ore-lodes in adjacent boreholes was further studied according to their depths, rock characters and orientation of lodes. Finally, a case study of the ore-lodes of adjacent boreholes in certain mining area was carried out and it is proved to be available for researching the connectivity of deep ore-lodes in adjacent boreholes by digital borehole camera technology.

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Disaster Avoidance in Industries through Weld Flaw detection from Radiographic Weld Images using Radon Transform and Improved Fuzzy C-Means Clustering

Vaithiyanathan V.,1* Anishin Raj M.M.1 and Venkatraman B.2

The weld flaw detection using image processing techniques helps in avoiding huge disaster in industries such as petrochemical, power generation and nuclear power plant, since this automated defect detection is more reliable and faster than other techniques. This paper proposes a new advanced Fuzzy c-Means (FCM) clustering for the detection of weld defect in radiographic images which arise due to various reasons which affect adversely at the time of welding process. The welding defect such as Burn-through, Lack of Penetration and Slag Inclusion can lead to disaster if undetected at the initial stage of installation of the machine or pipeline etc. Feature extraction is the process of detecting and isolating the distinguishable features for pattern identification which plays a major role in the success of pattern recognition. This paper adopted a new method of extracting feature vector by performing Radon transform for a single angle along the major orientation axis of the weld defect. This paper also proposes a new improved FCM clustering where the objective function is minimised in less number of iterations when compared with ordinary FCM and Hard c-Means. The implementation and result analysis of clustering shows that a better veracity is achieved in less number of iterations with the proposed advanced FCM with Radon transform based feature extraction when compared to Zernike moment based feature extraction.

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Numerical Simulation of Tectonic Stress Field in Longmenshan Tectonic Belts

He Hujun1,3, Su Shengrui2, Zhang Ying2 and Li Peng2

Two-dimensional finite element model of Longmenshan area was built on the basis of depth study on geological structure conditions and of rock mechanical properties in Longmenshan area. Tectonic stress field and variation process of Longmenshan fault belt were inversed before the earthquake, in the earthquake and after the earthquake. The results show that: (1) the direction of maximum main stress in the study area has regionalization, according to stress direction differences before the earthquake, in the earthquake and after the earthquake and can be divided into the southwest region of Houshan fault, the middle section of Houshan fault, the region near Yingxiu of central fault, Xiaoyudong area between central fault and Qianshan fault, the region between Qingping village of central fault and Guangming village of Houshan fault, the region between central fracture and Houshan fault in the west of Beichuan. (2) there are local shear stress concentration areas in Longmenshan fault zone before the earthquake and in the earthquake, especially near Yingxiu but after the earthquake, shear stress distribution is more uniform. Shear stress concentration zone of Longmenshan central fault presents the migration at northeast, the most prominent near Yingxiu.

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On the Characteristics of the Hourly Precipitation Intensity Variation according to Climate Change in the Korean Peninsula

Park Jong-Kil1*, Seong Ihn-Cheol2, Kim Baik-Jo3, Jung Woo-Shik4 and Lu Riyu5

In the present study, hourly precipitation data collected over 40 years (1970–2009) from 26 points throughout the country were used. Using those data, the changing trends in precipitation patterns and hourly precipitation intensities in relation to regional climate change were studied in order to analyze the trend of events of heavy rain concentrated during several hours and the resulting increases in damage. Over the last 40 years, whereas the total annual amounts of precipitation in the Busan region increased slightly, the average hourly precipitation intensity (28.2%) increased much faster than the average daily precipitation intensity (5.0%). Although the frequency and amount of precipitation of 5 mm/h or lower hourly precipitation intensities decreased, those of 10 mm/h or higher hourly precipitation intensities increased and those of 30 mm/h or higher hourly precipitation intensities increased greatly. Thus, as hourly precipitation intensities increased, their frequency and the amounts of precipitation increased particularly fast. The amounts of precipitation, precipitation frequencies and precipitation intensities at 26 points throughout the country were compared. The results showed that the amounts of precipitation and hourly precipitation intensities increased, along with frequencies, faster than daily precipitation intensities. The entire Korean Peninsula showed characteristics similar to those of Busan, although there were some differences between points.

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A Method for Building Block Model 0f Layered Geologic Object from Geological Cross-Section Data

Chen Guoliang1* and Liu Xiuguo2

Some new data-processing methods and modeling algorithms are developed on the base of multi-layer modeling technology which is a direct and effective way to build layered geological objects. A method to extract the arc of geological cross-section quickly is presented which enhances the interpolation efficiency in building the interface of strata levels. Then, a new algorithm, in terms of the overlapping interface between upper and lower strata levels is provided to build geological block. The algorithm first sets different label for each triangle of each stratigraphic surface and then separates each stratigraphic surface into some sub-surfaces by the breadth-first search algorithm. Finally, the geological blocks of each stratum are established quickly according to the relationship between these sub-surfaces. To reduce the redundant data generated from stratigraphic surface intersection in each strata level, a simplified algorithm for geological modeling is presented which is benefit for subsequent visualization and analysis. The methods and algorithms above are programmed as a special module on the MapGIS-TDE platform and then the 3D geological model of urban groundwater in a certain region is built by this module. The results show that the methods and algorithms are feasible for geological modeling.

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Spatial and Temporal Distribution of Earthquakes Disasters in China’s Northwest Region

Ying Wang1,2* and Juan Li 1, 2

Earthquakes are major Natural disasters affecting the Northwest region and every year there are destructive earthquakes above magnitude 5 occurring in this region. According to the catalogue of historical earthquakes above Ms 5, the characteristics of their spatial distribution are: nearly 60% of the county-level administrative regions have experienced earthquakes above magnitude 5, earthquakes above Ms 6 are concentrated in nine seismic belts. Earthquakes above magnitude 5 and 6 follow Poisson distribution. If 83 days have elapsed since the last earthquake, then the probability of an earthquake of Ms ≥ 5.0 occurring will be 80%; if there are 505 days of quiescence following an earthquake of Ms ≥ 6.0, then there is also a 80% probability of earthquake occurrence. The frequency of destructive earthquakes in the Northwest region is higher between 16:00 and 17:00 each day than during other periods; great importance must be attached to this when defending against earthquakes. Historical record shows that Shaanxi and Gansu provinces have the highest death tolls from earthquakes and Qinghai Province has the lowest death toll from earthquakes. Due to poor seismic resistance of residential buildings, an earthquake of the same magnitude will be a greater disaster in the Northwest region than in China’s other regions with a similar level of economic development.

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