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1.
Geostatistical topographic analysis is widely recognized as a useful tool for the statistical reconstruction of planar geomorphic markers from relict surfaces. This work is aimed at improving the geostatistical approach used in previous works and developing a method for evaluating the incision rates of rivers in their lower catchments during the Late Quaternary. We chose the major valleys of the Adriatic foothills (central Italy), affected since Late Miocene by a differential tectonic uplift which is still active. In particular, (i) we applied the geostatistical analysis to reconstruct the original top‐surfaces of fluvial‐to‐coastal terrace bodies at the Metauro River and Cesano River mouths; (ii) we performed correlations between the height distribution of the alluvial terrace sequences and the Quaternary climatic curve to estimate the average long‐term fluvial incision rates in the lowermost reaches of the Metauro, Cesano, Misa and Esino Rivers. The obtained averaged incision rates have been interpreted also in the light of the Stream‐Length Gradient Index (SL Index), Steepness Index (Ks), and Concavity Index (θ) as proxies of the stream‐power per unit length. Results confirm that geostatistical and terrain analysis of topographic and geometric arrangements of fluvial and coastal terraces is an effective tool in detecting geomorphic and tectonic factors inducing perturbations on planar geomorphic markers. In particular, we better delineated the surface geometry and boundaries of well‐developed coastal fans at the mouths of the Metauro and Cesano Rivers, already recognized in previous works through sedimentological, morphostratigraphic, and chronological data. Moreover, we found evidence for cut‐and‐fill phases that took place during and immediately after the river aggradation of the late Quaternary glacial periods. Despite the Slope–Area analysis evidenced a widespread influence of the regional differential uplift on single river basin configuration, we observed some space and time variability of averaged incision rates for adjacent valleys, mainly explained by physiographic configuration and dynamics of drainage network. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
2.
Justin C. Stout Ian Rutherfurd James Grove J. Angus Webb Adrian Kitchingman Zeb Tonkin 《地球表面变化过程与地形》2017,42(4):647-656
Reporting uncertainty in environmental measurements and estimates is important for cross‐comparison and inter‐comparison of sites and other spatial units. One such measure is the load of large in‐stream wood in river systems. In this paper we propose the use of the Weibull distribution to describe the central tendency and variability of wood loads along a river reach. We illustrate the link between the average wood load and the central tendency or scale parameter of the Weibull distribution. The shape of the Weibull distribution is strongly related to the ability of rivers to transport and rearrange the wood in a reach. We use six Victorian rivers to test the fit of the Weibull distribution, showing that the Weibull is a useful and flexible distribution that provides common reporting metrics useful for future studies. Using common reporting metrics provides a stronger tool for comparisons of wood loads between rivers and with reaches. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
3.
Our objective is to understand general causes of different river channel patterns. In this paper we compare an empirical stream power‐based classification and a physics‐based bar pattern predictor. We present a careful selection of data from the literature that contains rivers with discharge and median bed particle size ranging over several orders of magnitude with various channel patterns and bar types, but no obvious eroding or aggrading tendency. Empirically a continuum is found for increasing specific stream power, here calculated with pattern‐independent variables: mean annual flood, valley gradient and channel width predicted with a hydraulic geometry relation. ‘Thresholds’, above which certain patterns emerge, were identified as a function of bed sediment size. Bar theory predicts nature and presence of bars and bar mode, here converted to active braiding index (Bi). The most important variables are actual width–depth ratio and nonlinearity of bed sediment transport. Results agree reasonably well with data. Empirical predictions are somewhat better than bar theory predictions, because the bank strength is indirectly included in the empirical prediction. In combination, empirical and theoretical prediction provide partial explanations for bar and channel patterns. Increasing potential‐specific stream power implies more energy to erode banks and indeed correlates to channels with high width–depth ratio. Bar theory predicts that such rivers develop more bars across the width (higher Bi). At the transition from meandering to braiding, weakly braided rivers and meandering rivers with chutes are found. Rivers with extremely low stream power and width–depth ratios hardly develop bars or dynamic meandering and may be straight or sinuous or, in case of disequilibrium sediment feed, anastomosing. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
4.
我国海洋地质地球物理工作起步晚,整体调查程度较低,进一步加强我国海洋地学编图显得十分必要.我国实施的"海洋地质保障工程",将分"中国海陆"、"中国海及邻域"和"中国各海区"三个层次来进行地学编图.第一层次编制了空间重力异常图、布格重力异常图、磁力异常图、地震层析成像图、莫霍面深度图、地质图、大地构造格架图和大地构造格架演化图等8种图件.编图反映出中国海陆重力异常是"线性异常带纵横交错,块状异常区坐落其间"、重力梯级带主要为块体结合带;陆地磁力异常大致正负磁异常相间分布,海域北部为沟-弧-盆相关异常、南部磁条带异常;莫霍面总体特征为"东西分带,南北分块";地震层析成像反映出中国东部和西部岩石层厚度的差异以及上地幔软流层的分布特点;大地构造格架和演化图再现了块体体制向板块体制的转换过程.本次编图强调地球深部结构的变化对表层构造的关联,重视地球物理资料与地质构造的结合,以深-浅层结合来划分中国大地构造格架.已有成果表明,中国海陆大地构造格局可以用"块体构造学说"来描述. 相似文献
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6.
Based on DEM data and ArcGIS software, we extract the geomorphic parameters of drainage basins and rivers that flow through the Huashan piedmont, which include stream length-gradient index (SL), stream-power incision model normalized channel steepness index (ksn), hypsometric integral (HI), valley floor width to valley height ratio (Vf)and mountain front sinuosity (Smf). Study shows that all parameter indexes have obviously different distributions roughly bounded by Huaxian and Huayin. In the Huaxian to Huayin section, the stream length-gradient index has extremely high abnormal values near the fault, the values of river mean SL, mean ksn, HI, Vf and Smf are concentrated in 500~700, 120~140, 0.5~0.6, 0~0.1 and 1.0~1.1, respectively. Between Lantian and Huaxian and between Huayin and Lingbao, the parameter indexes distributional characteristics are largely the same, with the values in 300~500, 100~120, 0.4~0.5, 0.2~0.6 and 1.2~1.5, respectively. Comprehensive analysis suggests that tectonic activity is the primary factor responsible for these differences. We divide each geomorphic parameter into three classes (strong, medium, and low)and calculate the relative active tectonics (Iat)of the Huashan piedmont. The results show that the Iat values in Huaxian to Huayin section are in 1.0~1.5, those at other places are in 1.5~3.0, indicating that the tectonic activity from Huaxian to Huayin is most intense, while that of other places are relatively weak. Field geological investigations show that the Huashan piedmont fault can be divided into Lantian to Huaxian section, Huaxian to Huayin section and Huayin to Lingbao section. In Huaxian to Huayin section the fault has been active several times since Holocene indicative of strongest activity, while in Lantian to Huaxian section and Huayin to Lingbao section the fault was active only in the late Pleistocene and its activity was weaker as a whole. Tectonic activity of the Huashan piedmont derived from river geomorphic parameters is consistent with field geological investigations, indicating that geomorphic parameters of rivers can be used to characterize activity of faults on a regional scale. 相似文献
7.
The equilibrium form of the fluvial long profile has been used to elucidate a wide range of aspects of landscape history including tectonic activity in tectonic collision zones, and in continental margin and other intraplate settings, as well as other base‐level changes such as due to sealevel fluctuations. The Hack SL form of the long profile, which describes a straight line on a log–normal plot of elevation (normal) versus distance (logarithmic), is the equilibrium long profile form that has been most widely used in such studies; slope–area analysis has also been used in recent years. We show that the SL form is a special case of a more general form of the equilibrium long profile (here called the DS form) that can be derived from the power relationship between stream discharge and downstream distance, and the dependence of stream incision on stream power. The DS form provides a better fit than the SL form to river long profiles in an intraplate setting in southeastern Australia experiencing low rates of denudation and mild surface uplift. We conclude that, if an a priori form of the long profile is to be used for investigations of regional landscape history, the DS form is preferable. In particular, the DS form in principle enables equilibrium steepening due to an increase in channel substrate lithological resistance (parallel shift in the DS plot) to be distinguished from disequilibrium steepening due to long profile rejuvenation (disordered outliers on the DS plot). Slope–area analysis and the slope–distance (DS) approach outlined here are complementary approaches, reflecting the close relationship between downstream distance and downstream catchment area. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
8.
Mountainous river basins are one of the main sources of sediment. Over long time scales, sediment production is sustained by the persistent dissection of river basins, which is promoted by tectonic activity. The response or adjustment of rivers to forcing factors such as uplift is based on the concept of the graded river and a feedback mechanism between the incision and uplift. Although the development of graded rivers under natural circumstances has been discussed for a long time, knowledge about the transition of river basins under heterogeneous uplift is not enough. To understand the development of a river basin with a non‐uniform uplift rate, two simple cases are examined: landward and seaward tilting uplift, where the uplift rate varies linearly in space. For our study, laboratory experiments were conducted and the results were compared with those of natural river basins; two river basins in Yakushima Island were selected for this purpose. In both the laboratory and Yakushima, the longitudinal profile of the river basin under landward‐tilting uplift has a convex‐up zone and a specific knickpoint is formed at the upstream end of this zone. This knickpoint is inactive with respect to migration and incision owing to the insufficient cumulative uplift to the equilibrium state. It was also observed in both the experimental and natural cases that the profile of the river basin under seaward tilting is unlikely to have such a convex‐up zone in the long term, and will instead have a smooth concave profile. Therefore, the spatiotemporal pattern of dissection differs depending on the type of tilting uplift, which suggests that sediment production also varies in time and space according to the type of uplift. 相似文献
9.
Groundwaters feeding travertine‐depositing rivers of the northeastern segment of the Barkly karst (NW Queensland, Australia) are of comparable chemical composition, allowing a detailed investigation of how the rate of downstream chemical evolution varies from river to river. The discharge, pH, temperature, conductivity and major‐ion concentrations of five rivers were determined by standard field and laboratory techniques. The results show that each river experiences similar patterns of downstream chemical evolution, with CO2 outgassing driving the waters to high levels of calcite supersaturation, which in turn leads to widespread calcium carbonate deposition. However, the rate at which the waters evolve, measured as the loss of CaCO3 per kilometre, varies from river to river, and depends primarily upon discharge at the time of sampling and stream gradient. For example, Louie Creek (Q = 0·11 m3 s?1) and Carl Creek (Q = 0·50 m3 s?1) have identical stream gradients, but the loss of CaCO3 per kilometre for Louie Creek is twice that of Carl Creek. The Gregory River (Q = 3·07 m3 s?1), O'Shanassy River (Q = 0·57 m3 s?1) and Lawn Hill Creek (Q = 0·72 m3 s?1) have very similar gradients, but the rate of hydrochemical evolution of the Gregory River is significantly less than either of the other two systems. The results have major implications for travertine deposition: the stream reach required for waters to evolve to critical levels of calcite supersaturation will, all others things being equal, increase with increasing discharge, and the length of reach over which travertine is deposited will also increase with increasing discharge. This implies that fossil travertine deposits preserved well downstream of modern deposition limits are likely to have been formed under higher discharge regimes. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
10.
At watershed extents, our understanding of river form, process and function is largely based on locally intensive mapping of river reaches, or on spatially extensive but low density data scattered throughout a watershed (e.g. cross sections). The net effect has been to characterize streams as discontinuous systems. Recent advances in optical remote sensing of rivers indicate that it should now be possible to generate accurate and continuous maps of in‐stream habitats, depths, algae, wood, stream power and other features at sub‐meter resolutions across entire watersheds so long as the water is clear and the aerial view is unobstructed. Such maps would transform river science and management by providing improved data, better models and explanation, and enhanced applications. Obstacles to achieving this vision include variations in optics associated with shadows, water clarity, variable substrates and target–sun angle geometry. Logistical obstacles are primarily due to the reliance of existing ground validation procedures on time‐of‐flight field measurements, which are impossible to accomplish at watershed extents, particularly in large and difficult to access river basins. Philosophical issues must also be addressed that relate to the expectations around accuracy assessment, the need for and utility of physically based models to evaluate remote sensing results and the ethics of revealing information about river resources at fine spatial resolutions. Despite these obstacles and issues, catchment extent remote river mapping is now feasible, as is demonstrated by a proof‐of‐concept example for the Nueces River, Texas, and examples of how different image types (radar, lidar, thermal) could be merged with optical imagery. The greatest obstacle to development and implementation of more remote sensing, catchment scale ‘river observatories’ is the absence of broadly based funding initiatives to support collaborative research by multiple investigators in different river settings. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
11.
River networks have been shown to obey power scaling laws and to follow self‐organization principles. Their self‐similar (fractal) properties open a path to relate small scale and large scale hydrological processes, such as erosion, deposition or geological movements. However, the existence of a self‐similar dimension has only been checked using either the whole channel network or, on the contrary, a single channel link. No study has explicitly addressed the possible spatial variation of the self‐similar properties between these two extreme geomorphologic objects. Here, a new method based on self‐similarity maps (SSM) is proposed to spatially explore the stream length self‐similar dimension Dl within a river network. The mapping principle consists in computing local self‐similar dimensions deduced from a fit of stream length estimations using increasing divider sizes. A local uncertainty related to the fit quality is also computed and localized on every stream. To assess the efficiency of the approach, contrasted river networks are simulated using optimal channel networks (OCN), where each network is characterized by an exponent γ conditioning its overall topology. By building SSM of these networks, it is shown that deviations from uniform self‐similarity across space occur. Depending on the type of network (γ parameter), these deviations are or are not related to Strahler's order structure. Finally, it is found numerically that the structural averaged stream length self‐similar dimension Dl is closely related to the more functional γ parameter. Results form a bridge between the studies on river sinuosity (single channel) and growth of channel networks (watershed). As for every method providing spatial information where they were lacking before, the SSM may soon help to accurately interpret natural networks and help to simulate more realistic channel networks. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
12.
We present an aeromagnetic survey of the Gulf of Valencia and the Balearic Islands (western Mediterranean). A total field anomaly map and a map of the anomalies reduced to the pole have been obtained. From these maps, it is apparent that there are two regions of opposing magnetic style: the Balearic archipelago which is magnetically very smooth, and the north Balearic basin (or Gulf of Valencia) where anomalies are in places very intense. From a comparison of these two domains, we conclude that the Valencian basin was created during an extensional tectonic phase. 相似文献
13.
GEOMORPHIC FEATURES OF THE SHULE RIVER DRAINAGE BASIN IN QILIANSHAN AND ITS INSIGHT INTO TECTONIC IMPLICATIONS 
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下载免费PDF全文 SU Qi YUAN Dao-yang XIE Hong SHAO Yan-xiu LIANG Ming-jian. Lanzhou Institute of Seismology China Earthquake Administration Lanzhou China . Lanzhou National Observatory of Geophysic 《地震地质》2016,38(2):240-258
Because of the strong uplift of the Qilian Shan since late Cenozoic,the drainage basins that are derived from the mountains have undergone strong tectonic deformation.So the typical geomorphology characteristics of these drainage basins may indicate the strong tectonic movement in the region.For example,the Shule River drainage basin,which originates from the western part of the Qilian Shan owns unique geomorphology characteristics which may indicate the neotectonic movement.
Stream networks of the Shule drainage basin extracted from the DEM data based on GIS spatial analysis technology are graded into five levels using Strahler classification method.Four sub-catchments,numbered 1,2,3 and 4 are chosen for detailed analysis.Furthermore,the four sub-catchments,the hypsometric integral curves,Hack profiles,SL index and average slope of the Shule drainage basin are determined by GIS tools.In addition,we analyzed the slope spectrum of the Shule drainage basin.
The average elevation of the Shule drainage basin is very high,however,the slope of the drainage basin is very low,the gentle slope occupies so large area proportion that the slope spectrum shows a unimodal pattern and a peak value is in low slope region (0°~5°),so tectonic movement has a strong influence on the drainage basin.Under the intensive impact of the tectonic movement of the active fault and regional uplift,the hypsometric integral curve is sigmoid,revealing that the Shule drainage basin is in the mature stage.The Hack profile is on a convex,the longitudinal profile is best fitted by linear fitting and the abnormal data of the SL index of the Shule River has a good fit with the section through which the active fault traverses,that means the tectonic movement of the active fault has strong influence on the river's SL index.It is worth noting that lithologic factors also have great impact on the river geomorphology in some sections.
According to the above analysis,we recognize that in the interior of active orogen,the evolution of river geomorphology usually is influenced by tectonic movement and reveals the regional neotectonics in turn. 相似文献
14.
V.N.Golosov 《国际泥沙研究》1996,(2)
ＳＯＭＥＡＰＰＲＯＡＣＨＥＳＦＯＲＳＴＵＤＹＩＮＧＴＨＥＩＮＴＥＮＳＩＴＹＯＦＳＭＡＬＬＲＩＶＥＲＡＧＧＲＡＤＡＴＩＯＮＶ．Ｎ．Ｇｏｌｏｓｏｖ（ＬａｂｏｒａｔｏｒｙｏｆＳｏｉｌａｎｄＦｌｕｖｉａｌＰｒｏｃｅｓｓｅｓ，ＦａｃｕｌｔｙｏｆＧｅｏｇｒａｐｈ... 相似文献
15.
Ayd?n Büyüksaraç 《Physics of the Earth and Planetary Interiors》2007,160(1):86-95
The residual aeromagnetic and gravity anomalies of inner East Anatolia, surveyed by the Mineral Research and Exploration (MTA) of Turkey, display complexities. Some faults, which are known and new lineaments, are drawn from maxspot map derived from the location of the horizontal gradient of gravity anomalies. Tectonic lineaments of inner East Anatolia exhibit similarities to the direction of East Anatolian Fault Zone. Anticlockwise rotation, approximately −30°, defined from disorientations of aeromagnetic anomalies. The lineaments obtained from maxspots map produced from the gravity anomalies and disoriented aeromagnetic anomalies are in-line with the mobilistic system revealed by the palaeomagnetic data. These Alpine age continental rotations caused westward wrenching of the global lithosphere and led to significant tectonic reactivation and deformations. GPS measurements, current tectonic knowledge and the results of the evaluation of potential field data were combined in a base map to demonstrate similarities. 相似文献
16.
Modelling hydrological connectivity of tropical floodplain wetlands via a combined natural and artificial stream network 下载免费PDF全文
下载免费PDF全文 Fazlul Karim Anne Kinsey‐Henderson Jim Wallace Paul Godfrey Angela H. Arthington Richard G. Pearson 《水文研究》2014,28(23):5696-5710
The ecological condition and biodiversity values of floodplain wetlands are highly dependent on the hydrological connectivity of wetlands to adjacent rivers. This paper describes a method for quantifying connectivity between floodplain wetlands and the main rivers in a wet tropical catchment of northern Australia. We used a one‐dimensional hydrodynamic model to simulate time‐varying water depths across the stream network (i.e. rivers, streams and man‐made drains). The timing and duration of connectivity of seven wetlands (four natural and three artificial) with the two main rivers in the catchment were then calculated for different hydrological conditions. Location and areal extent of the wetlands and the stream network were identified using high‐resolution laser altimetry, and these data formed key inputs to the hydrodynamic model. The model was calibrated using measured water depths and discharges across the floodplain. An algorithm was developed to identify contiguous water bodies at daily time steps, and this gave the temporal history of connection and disconnection between wetlands and the rivers. Simulation results show that connectivity of individual wetlands to both rivers varies from 26 to 365 days during an average hydrological condition. Location, especially proximity to a main river, and wetland type (natural stream or artificial drain) were identified as key factors influencing these levels of connectivity. Some natural wetlands maintain connection with the river for most or all of the year, whereas the connectivity of some artificial wetlands varies from 26 to 36 days according to their patterns of network connection to adjacent rivers – a result that has important implications for the accessibility of these types of wetland to aquatic biota. Using readily available river gauge data, we also show how connectivity modelling can be used to identify periods when connectivity has fallen below critical thresholds for fish movement. These connectivity patterns within the floodplain network are central to the setting of river flows that will meet environmental requirements for biota that use floodplain wetlands during their life history. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
17.
Modelling wetland connectivity during overbank flooding in a tropical floodplain in north Queensland,Australia 总被引：2，自引：0，他引：2
Fazlul Karim Anne Kinsey‐Henderson Jim Wallace Angela H. Arthington Richard G. Pearson 《水文研究》2012,26(18):2710-2723
Hydrological connectivity between floodplain wetlands and rivers is one of the principal driving mechanisms for the diversity, productivity and interactions of the major biota in river–floodplain systems. This article describes a method of quantifying flood‐induced overbank connectivity using a hydrodynamic model (MIKE 21) to calculate the timing, the duration and the spatial extent of the connections between several floodplain wetlands and rivers in the Tully–Murray catchment, north Queensland, Australia. Areal photogrammetry and field surveyed stream cross data were used to reproduce floodplain topography and rivers in the model. Laser altimetry (LiDAR)–derived fine resolution elevation data, for the central floodplain, were added to the topography model to improve the resolution of key features including wetlands, flow pathways and natural and artificial flow barriers. The hydrodynamic model was calibrated using a combination of in‐stream and floodplain gauge records. A range of off‐stream wetlands including natural and artificial, small and large were investigated for their connectivity with two main rivers (Tully and Murray) flowing over the floodplain for flood events of 1‐, 20‐ and 50‐year recurrence intervals. The duration of the connection of individual wetlands varied from 1 to 12 days, depending on flood magnitude and location in the floodplain, with some wetlands only connected during large floods. All of the wetlands studied were connected to the Tully River for shorter periods than they were to the Murray River because of the higher bank heights and levees on the Tully River and wetland proximity to the Murray River. Other than hydrology, land relief, riverbank elevation and levee banks along the river were found key factors controlling the degree of connectivity. These variations in wetland connectivity could have important implications for aquatic biota that move between rivers and off‐stream habitats during floods. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
18.
There are many field techniques used to quantify rates of hyporheic exchange, which can vary in magnitude and direction spatially over distances of only a few metres, both within and between morphological features. We used in‐stream mini‐piezometers and heat transport modelling of stream and streambed temperatures to quantify the rates and directions of water flux across the streambed interface upstream and downstream of three types of in‐stream geomorphic features: a permanent dam, a beaver dam remnant and a stream meander. We derived hyporheic flux estimates at three different depths at six different sites for a month and then paired those flux rates with measurements of gradient to derive hydraulic conductivity (K) of the streambed sediments. Heat transport modelling provided consistent daily flux estimates that were in agreement directionally with hydraulic gradient measurements and also identified vertical heterogeneities in hydraulic conductivity that led to variable hyporheic exchange. Streambed K varied over an order of magnitude (1·9 × 10?6 to 5·7 × 10?5 m/s). Average rates of hyporheic flux ranged from static (q < ±0·02 m/day) to 0·42 m/day. Heat transport modelling results suggest three kinds of flow around the dams and the meander. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
19.
Stephen J. Dugdale Christa A. Kelleher Iain A. Malcolm Samuel Caldwell David M. Hannah 《水文研究》2019,33(7):1152-1163
Climate change is altering river temperature regimes, modifying the dynamics of temperature‐sensitive fishes. The ability to map river temperature is therefore important for understanding the impacts of future warming. Thermal infrared (TIR) remote sensing has proven effective for river temperature mapping, but TIR surveys of rivers remain expensive. Recent drone‐based TIR systems present a potential solution to this problem. However, information regarding the utility of these miniaturised systems for surveying rivers is limited. Here, we present the results of several drone‐based TIR surveys conducted with a view to understanding their suitability for characterising river temperature heterogeneity. We find that drone‐based TIR data are able to clearly reveal the location and extent of discrete thermal inputs to rivers, but thermal imagery suffers from temperature drift‐induced bias, which prevents the extraction of accurate temperature data. Statistical analysis of the causes of this drift reveals that drone flight characteristics and environmental conditions at the time of acquisition explain ~66% of the variance in TIR sensor drift. These results shed important light on the factors influencing drone‐based TIR data quality and suggest that further technological development is required to enable the extraction of robust river temperature data. Nonetheless, this technology represents a promising approach for augmenting in situ sensor capabilities and improved quantification of advective inputs to rivers at intermediate spatial scales between point measurements and “conventional” airborne or satellite remote sensing. 相似文献
20.
Petar Stavrev 《Geophysical Prospecting》2006,54(2):153-166
The calculable magnitudes of the anomalous magnetic field from simple 2D sources and their gradients and Laplacians appear as ratios that can be synthesized in functional forms, corresponding to the different source shapes. Field components and first‐order derivatives are involved in the inversion procedures presented. The structural index and source depth are estimated independently of each other. The applied functions allow magnetic profiles and magnetic maps to be shape‐ and depth‐converted with immediate imaging of the inversion results. The contours of these functions outline elongated loops around the 2.5D anomaly axis on magnetic maps. The width of the loops reflects the depth and structural index N of the source in the scale units of the inverted map. Model and field tests illustrate the effectiveness of this approach for fast automatic inversion of large sets of magnetic data for depth, shape, length and location of simple sources. 相似文献