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1.
《Geodinamica Acta》1999,12(3-4):193-200
In northeast Vietnam, the karst of Halong Bay is characterized by very active neotectonics. The directional distribution of fracturing of the calcareous rocks is characterized by the influence of two major fault zones: the Red River fault zone (N140) and the Tan-Lu fault zone (N050). Karst development was favoured by intense fracturing, according to these two major directions, and reactived during recent tectonics by a compressional regime with σ1 N070, followed by an extensional regimes with σ1 near to EW that led to significant vertical movement. These tectonics, coupled with intense erosion, led to genesis and evolution of the spectacular morphology of this peak karst.  相似文献   

2.
At the end of the western part of Bagharan Kuh Mountain in the northeast of Iran, mountain growth has been stopped toward the west because of the stress having been consumed by the thrusting movements and region rising instead of shear movement. Chahkand fault zone is situated at the western part of this mountain; this fault zone includes several thrust sheets that caused upper cretaceous ophiolite rocks up to younger units, peridotite exposure and fault related fold developing in the surface. In transverse perpendicular to the mountain toward the north, reduction in the parameters like faults dip, amount of deformation, peridotite outcrops show faults growth sequence and thrust sheets growth from mountain to plain, thus structural vergence is toward the northeast in this fault zone. Deformation in the east part of the region caused fault propagation fold with axial trend of WNW-ESE that is compatible with trending of fault plane. In the middle part, two types of folds is observed; in the first type, folding occurred before faulting and folds was cut by back thrust activity; in the second type, faults activity caused fault related folds with N60-90W axial trend. In order to hanging wall strain balance, back thrusts have been developed in the middle and western part which caused popup and fault bend folds with N20-70E trend. Back thrusts activity formed footwall synclines, micro folds, foliations, and uplift in this part of the region. Kinematic analysis of faults show stress axis σ1 = N201.6, 7, σ2 = N292.6, 7.1, σ3 = N64.8, 79.5; stress axis obtained by fold analysis confirm that minimum stress (σ3) is close to vertical so it is compatible with fault analysis. Based on the results, deformation in this region is controlled by compressional stress regime. This stress state is consistent with the direction of convergence between the Arabian and Eurasian plates. Also study of transposition, folded veins, different movements on the fault planes and back thrusts confirm the progressive deformation is dominant in this region that it increases from the east to the west.  相似文献   

3.
The Western Alps’ active tectonics is characterized by ongoing widespread extension in the highest parts of the belt and transpressive/compressive tectonics along its borders. We examine these contrasting tectonic regimes using a multidisciplinary approach including seismotectonics, numerical modeling, GPS, morphotectonics, fieldwork, and brittle deformation analysis. Extension appears to be the dominant process in the present-day tectonic activity in the Western Alps, affecting its internal areas all along the arc. Shortening, in contrast, is limited to small areas located along at the outer borders of the chain. Strike-slip is observed throughout the Alpine realm and in the foreland. The stress-orientation pattern is radial for σ3 in the inner, extensional zones, and for σ1 in the outer, transcurrent/tranpressional ones. Extensional areas can be correlated with the parts of the belt with the thickest crust. Quantification of seismic strain in tectonically homogeneous areas shows that only 10–20% of the geodesy-documented deformation can be explained by the Alpine seismicity. We propose that, Alpine active tectonics are ruled by isostasy/buoyancy forces rather than the ongoing shortening along the Alpine Europe/Adria collision zone. This interpretation is corroborated by numerical modeling. The Neogene extensional structures in the Alps formed under increasingly brittle conditions. A synthesis of paleostress tensors for the internal parts of the West-Alpine Arc documents major orogen-parallel extension with a continuous change in σ3 directions from ENE–WSW in the Simplon area, to N–S in the Vanoise area and to NNW–SSE in the Briançon area. Minor orogen-perpendicular extension increases from N to S. This second signal correlates with the present-day geodynamics as revealed by focal-plane mechanisms analysis. The orogen-parallel extension could be related to the opening of the Ligurian Sea during the Early-Middle Miocene and to compression/rotation of the Adriatic indenter inducing lateral extrusion.  相似文献   

4.
Abstract

In New Zealand, the Marlborough strike-slip faults link the Hikurangi subduction zone to the Alpine fault collision zone. Stratigraphic and structural analysis in the Marlborough region constrain the inception of the current strike-slip tectonics.

Six major Neogene basins are investigated. Their infill is composed of marine and freshwater sediments up to 3 km thick; they are characterised by coarse facies derived from the basins bounding relief, high sedimentation rates and asymmetric geometries. Proposed factors that controlled the basins generation are the initial geometry of the strike-slip faults and the progressive strike-slip motion. Two groups of basins are presented: the early Miocene (23 My) basins were generated under wrench tectonics above releasing-jogs between basement faults. The late Miocene (11 My) basins were initiated by halfgrabens tilted along straighter faults during a transtensive stage. Development of faults during Cretaceous to Oligocene times facilitated the following propagation of wrench tectonics. The Pliocene (5 My) to current increasing convergence has shortened the basins and distorted the Miocene array of faults. This study indicates that the Marlborough Fault System is an old feature that connected part of the Hikurangi margin to the Alpine fault since the subduction and collision initiation. © Elsevier, Paris  相似文献   

5.
ABSTRACT

At the end of the Cenozoic, western Turkey was fragmented by intense intra-continental tectonic deformation resulting in the formation of two extensional areas: a transtensional pull-apart basin systems in the northwest, and graben systems in the central and southwest areas. The question of the connection of this Late Cenozoic extensional tectonics to plate kinematics has long been an issue of discussion. This study presents the results of the fault slip data collected in Bak?rçay Basin in the west of Turkey and addresses changes in the direction of extensional stresses over the Plio-Quaternary. Field observations and quantitative analysis show that Bak?rçay Basin is not a simple graben basin that has evolved during a single phase. It started as a graben basin with extensional regime in the Pliocene and was transformed into a pull-apart basin under the influence of transtensional forces during the Quaternary. A chronology of two successive extensional episodes has been established and provides reasoning to constrain the timing and location of subduction-related back-arc tectonics along the Aegean region and collision-related extrusion tectonics in Turkey. The first NW–SE trending extension occurred during the Pliocene extensional phase, characterized by slab rollback and progressive steepening of the northward subduction of the African plate under the Anatolian Plate. Western Turkey has been affected, during the Middle Quaternary, by regional subsidence, and the direction of extension changed to N–S, probably in relation with the propagation of the North Anatolian Fault System. Since the Late Quaternary, NE–SW extension dominates northwest Turkey and results in the formation and development of elongated transtensional basin systems. Counterclockwise rotation of Anatolian block which is bounded to the north by the right-lateral strike-slip North Anatolian Fault System, accompanies to this extensional phase.  相似文献   

6.
This paper examines the morphotectonic and structural–geological characteristics of the Quaternary Martana Fault in the Umbria–Marche Apennines fold‐and‐thrust belt. This structure is more than 30 km long and comprises two segments: a N–NNW‐trending longer segment and a 100°N‐trending segment. After developing as a normal fault in Early Pleistocene times, the N–NNW Martana Fault segment experienced a phase of dextral faulting extending from the Early to Middle Pleistocene boundary until around 0.39 Ma, the absolute age of volcanics erupted in correspondence to releasing bends. The establishment of a stress field with a NE–ENE‐trending σ3 axis and NW–NNW σ1 axis in Late Pleistocene to Holocene times resulted in a strong component of sinistral faulting along N–NNW‐trending fault segments and almost pure normal faulting on newly formed NW–SE faults. Fresh fault scarps, the interaction of faulting with drainage systems and displacement of alluvial fan apexes provide evidence of the ongoing activity of this fault. The active left‐lateral kinematic along N–NNW‐trending fault segments is also revealed by the 1.8 m horizontal offset of the E–W‐trending Decumanus road, at the Roman town of Carsulae. We interpret the present‐day kinematics of the Martana Fault as consistent with a model connecting surface structures to the inferred north‐northwest trending lithospheric shear zone marking the western boundary of the Adria Plate. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

7.
Initiation and formation of folds and the Kazerun high-angle fault zone, in the Zagros fold-and-thrust belt, were related to the continuing SW–NE oriented contraction that probably initiated in the Late Cretaceous, and intensified, starting in Miocene, when the Arabian and Eurasian plates collided. The contraction that led to folding and thrusting of the Phanerozoic sequence in the belt has led to the strike–slip reactivation of basement faults that formed during the Precambrian. Two major systems of fractures have developed, under the same regional state of contraction, during the folding and strike–slip faulting processes. Folding led to the formation of a system of fold-related fractures that comprises four sets of fractures, which include an axial and a cross-axial set that trend parallel and perpendicular to the confining fold axial trace, respectively, and two oblique sets that trend at moderate angles to the axial trace. Slip along high-angle, strike–slip faults formed a system of fractures in the damage zone of the faults (e.g., Kazerun), and deformed folds that existed in the shear zone by rotating their axial plane. This fault-related fracture system is made of five sets of fractures, which include the two sets of Riedel shear fractures (R and R′), P- and Y-shear fractures, and an extensional set.

Remote sensing analysis of both fracture systems, in a GIS environment, reveals a related kinematic history for folding outside of the Kazerun shear zone and faulting and deformation (fracturing and rotation of folds) within the Kazerun fault zone. Rotation of the folds and formation of the five sets of the fault-related fractures in the Kazerun shear zone are consistent with a dextral motion along the fault. The mean trends of the shortening directions, independently calculated for the fold- and fault-related fracture systems, are remarkably close (N53 ± 4°E and N50 ± 5°E, respectively), and are perpendicular to the general NW–SE trend of the Zagros fold-and-thrust belt. Although segments of the Kazerun fault are variably oriented within a narrow range, the angular relationships between sets of fault-related fractures and these segments remain constant.  相似文献   


8.
陕西宁强禅家岩天坑群是汉中天坑群中 4 个相对独立的喀斯特系统之一,位于扬子陆块北缘,发育有多样的地质遗迹。文章通过大量野外勘测,总结出陕西宁强禅家岩天坑群地质遗迹的分布特点,并分析了主要地质遗迹的基本特征及形成原因,以揭示南北过渡带峡谷地貌下喀斯特的形成及演化机理。结果表明:（1）研究区形成了以天坑、台原、溶洞、峡谷以及次生化学沉积物为特色的2大类4类5亚类的地质遗迹;（2）区内喀斯特地貌典型,天坑和溶洞最为发育;（3）受峡谷深切影响,研究区内形成有4个地表喀斯特台原,其均具有相对独立的喀斯特水文地质特征,而天坑和竖井均已进入退化期;（4）在地层、岩性和构造多因素作用下,区内天坑孕育于新构造运动时期。   相似文献   

9.
Abstract: Four months after the Wenchuan Ms 8 earthquake in western Sichuan, China, in situ stress measurements were carried out along the Longmenshan fault zone with the purpose of obtaining stress parameters for earthquake hazard assessment. In-situ stresses were measured in three new boreholes by using overcoring with the piezomagnetic stress gauges for shallow depths and hydraulic fracturing for lower depths. The maximum horizontal stress in shallow depths (~20 m) is about 4.3 MPa, oriented N19°E, in the epicenter area at Yingxiu Town, about 9.7 MPa, oriented N51°W, at Baoxing County in the southwestern Longmenshan range, and about 2.6 MPa, oriented N39°E, near Kangding in the southernmost zone of the Longmenshan range. Hydraulic fracturing at borehole depths from 100 to 400 m shows a tendency towards increasing stress with depth. A comparison with the results measured before the Wenchuan earthquake along the Longmenshan zone and in the Tibetan Plateau demonstrates that the stress level remains relatively high in the southwestern segment of the Longmenshan range, and is still moderate in the epicenter zone. These results provide a key appraisal for future assessment of earthquake hazards of the Longmenshan fault zone and the aftershock occurrences of the Wenchuan earthquake.  相似文献   

10.
The seismotectonic deformations related to the Chuya earthquake September 27, 2003 in the Gorny Altai (Ms = 7.5) are studied in detail. These deformations developed as advanced systems of R-and R’-shears, gash fractures, and compression structural features in loose sediments. In bedrocks, the older shear zones were reactivated, the previously existing fractures were renewed and propagated further, and new faults and crush zones were formed. The system of seismic dislocations is a fault zone no less than 4 km wide that extends in the northwestern direction. As follows from the structural elements that reveal a systematic mutual orientation, the internal structure of this zone is typical of a right-lateral strike-slip fault. The initial stress field that led to the development of the entire assemblage of seismotectonic deformations related to the Chuya earthquake corresponds to the strike-slip type with the NNW, almost meridional direction of compression axis (σ1) and the ENE, almost latitudinal direction of the tension axis (σ3). The local variations of the stress state were expressed in an insignificant shift of σ1 to the northwest or northeast, in the short-term change of relative stress values with retention of their spatial orientation, and in the increasing inclination of σ1 in front of the previously existing fault. The comparison of the internal structure of the seismotectonic fault zone with a tectonophysical model of faulting in large continental systems with a right-lateral offset indicates that the distribution of the advanced faults corresponds to the late stage of faulting, when the main fault is still not formed completely, but its particular segments are already developed distinctly. It is shown that at high rates of displacement the structural features in markedly different rocks develop according to the general laws of solids’ deformation even near the day surface.  相似文献   

11.
郯庐断裂带的平移运动与成因   总被引：61，自引：4，他引：61  
在华北、华南板块碰撞期间，郯庐断裂带究竟是何种边界仍是没有解决的重大地学问题，许多学者对此提出了不同的构造解释模式。关于郯庐断裂的平移距离仍存在着较大的分歧与有待深入研究之处。在华北、华南板块拼合之后，郯庐断裂带发生了一次大规模的左行平移，其糜棱岩的^40Ar／^39Ar年龄为132～119Ma，指示为早白垩世的平移活动，平移活动中伴生了强烈的岩浆活动。这期左行平移标志着中国东部构造的重大转折，是滨太平洋构造对前期古特提斯构造的叠加，其动力学机制为太平洋区伊侨奈岐板块突然出现的高速斜向俯冲。  相似文献   

12.
ABSTRACT

The Late Mesozoic tectonics strongly reworked the tectonic framework of East Asia. In the South China Block (SCB), the major Late Mesozoic phenomena are featured by numerous magmatic activities, (half-) graben basins opening, and abundant ore deposits formation. The intrinsic relationships of these phenomena with the tectonic regime are still hotly debated, partly due to the lack of structural data. To advance the understanding of these issues, we conducted a detailed structural analysis including field and microscopic observations as well as an Anisotropy of Magnetic Susceptibility (AMS) investigation in the Laoshan’ao shear zone (LSA), which is the northern branch of the major Chaling–Chenzhou–Linwu Fault (CCLF) in the SCB. The new data enable us to reach the following conclusions: the evolution of the LSA can be divided into three deformation phases. D1 is a NW–SE-stretching event featured by the SE-dipping normal fault with a top-to-the-SE shear sense, coeval with the emplacement of the 154 Ma Batuan syn-tectonic pluton that leads to the development of the Xiangdong tungsten deposit and the opening of the Cretaceous Chaling basin; D2 is a NE–SW-striking dextral strike–slip event that dislocated the ore veins formed during the D1 event; D3 is a NW-directed thrusting event that cross-cut the previous gneissic foliation. D1 is the major event of the LSA shear zone, interpreted as the reactivation of the CCLF in response to the Late Mesozoic tectonics in the SCB, and indicates a NW-SE extensional regime since the Late Jurassic in the study area. This study also provides an example for an ore-forming process controlled by both the hydrothermal fluid coming from a syn-tectonic granite and the accommodation of tension gashes opened by the regional extensional event.  相似文献   

13.
淮北夹沟—桃山集地区推覆构造研究   总被引：1，自引：0，他引：1  
本区存在大型中生代推覆构造,所有震旦纪—古生代的沉积岩层都卷入了褶皱和断裂,构造推覆发生在较高构造部位,属脆性变形域,以台阶状逆断层和断层相关褶皱为特征。区内存在若干推覆构造,每个岩片均可分为上盘、下盘和滑动层系三部分,共查明8个滑动岩系。是一种发生在早中生代的盖层推覆,无根褶皱,也是徐宿地区最重要的控煤构造。最后对推覆构造的地球动力学机制进行了讨论。  相似文献   

14.
汶川地震后沿龙门山裂断带原地应力测量初步结果   总被引：2，自引：0，他引：2  
2008年5月12日在中国四川省西部汶川发生Ms8.0地震,震中位于青藏东缘龙门山断裂带。地震发生后的4个月,沿龙门山断裂带中南段开展了原地应力测量,获得了3个测点的应力大小和方向。在3个测孔中浅部采用压磁应力解除法,深部采用水压致裂法。浅部测量结果显示,位于震中区映秀测点,水平最大主应力值为4.3MPa,最大主应力方向为N19°E;宝兴测点位于震中区西南的龙门山断裂带南段,汶川地震没有导致该段地表破裂,该点获得的水平最大主应力值为9.8MPa,最大主应力方向为N51°W;位于龙门山断裂带最西南端的康定测点,水平最大主应力值为2.6MPa,最大主应力方向为N39°E。利用水压致裂法对各钻孔100～400m深度进行了应力测量,获得了应力随深度变化趋势和应力状态。与震前其它应力测量结果和中国其它地区表层地应力测量结果比较,龙门山断裂带西南段处于相对高应力水平,震中区仍处于中等应力水平。这项研究成果将为评价龙门山断裂带余震和今后强震发展趋势提供关键构造物理参数。  相似文献   

15.
Re-examination of the outcrop of conjugate of strike-slip faults mapped by Roday et al. (1989) near forest rest house at Hirapur reveals that the main dextral strike-slip fault that strikes N35°E and is a manifestation of the earliest NE-SW trending subhorizontal σ1 that produced extensional reef system in the Bundelkhand massif. Although the change in the stress system though 90° rotation of the principal compressive stress σ1 and σ3 (with σ2 maintaining near vertically) is correct, another point of interest is that the σ1 for the system of faults bisects the obtuse angle between the two sets and not an acute one as required by the brittle failure criterion. The sinistral strike-slip faults were probably formed by rejuvenation of the initial dextral strike-slip faults that were generated when the maximum principal compressive stress was oriented NS. The reversal of fault displacement is seen on all scales in the Bundelkhand massif. The dextral strike-slip fault related to the late stress system was preferentially produced along pre-existing tensile fractures that were generated under NE-SW directed subhorizontal σ1. Some of these fractures were converted into sinistral strike-slip faults under NS directed maximum principal compression acting subhorizontally.  相似文献   

16.
The recent tectonics of the Arctic Basin and northeastern Asia are considered as a result of interaction between three lithospheric plates: North-America, Eurasia and Spitsbergen. Seismic zones (coinciding in the Norway-Greenland basin with the Kolbeinsey, Mohns and Knipovich ridges, and in the Arctic Ocean with the Gakkel Ridge) clearly mark the boundaries between them. In southernmost Svalbard (Spitsbergen), the secondary seismic belt deviates from the major seismic zone. This belt continues into the seismic zone of the Franz Josef Land and then merges into the seismic zone of the Gakkel Ridge at 70°–90°E. The smaller Spitsbergen plate is located between the major seismic zone and its secondary branch.Within northeastern Asia, earthquake epicenters with magnitude over 4.5 are concentrated within a 300-km wide belt crossing the Eurasian continent over a distance of 3000 km from the Lena estuary to the Komandorskye Islands. A single seismic belt crosses the northern sections of the Verkhoyansky Ridge and runs along the Chersky Ridge to the Kolymo-Okhotsk Divide.To compute the poles of relative rotation of the Eurasian, North-American and Spitsbergen plates we use 23 new determinations of focal-mechanism solutions for earthquakes, and 38 azimuths of slip vectors obtained by matching of symmetric mountain pairs on both sides of the Knipovich and Gakkel ridges; we also use 14 azimuths of strike-slip faults within the Chersky Ridge determined by satellite images. The following parameters of plate displacement were obtained: Eurasia/North America: 62.2°N, 140.2°E (from the Knipovich Ridge section south of the triple junction); 61.9°N, 143.1°E (from fault strikes in the Chersky Ridge); 60.42°N, 141.56°C (from the Knipovich section and from fault strikes in the Chersky Ridge); 59.48°N, 140.83°E, α = 1.89 · 10−7 deg/year (from the Knipovich section, from fault strikes in the Chersky Ridge and from the Gakkel Ridge section east of the triple junction). The rate was calculated by fitting the 2′ magnetic lineations within the Gakkel Ridge).North-America/Spitsbergen: 70.96°N, 121.18°E, α = −2.7 · 10−7 deg/year from the Knipovich Ridge section north of the triple junction, from earthquakes in the Spitsbergen fracture zone and from the Gakkel Ridge section west of the triple junction). Eurasia/Spitsbergen: 70.7°N, 25.49°E, α = −0.99 · 10−7 deg/year (from closure of vector triangles).  相似文献   

17.
将大地电磁测深用于寻找深层地下水,在北京东部平谷盆地实施3条剖面25个测点,在资料分析过程中,对部分测点实施Mohr圆阻抗张量分解技术;在自动反演过程中,引入Rhoplus和Rebocc反演程序。通过对反演解释结果的分析,认为测区第四系地下水含量丰富,断裂构造及含水岩溶发育。对比3条剖面的电性分布特征,推测存在走向NNE的区域性断裂F1,其所经之处控制基岩中含水岩溶的发育;与F1相交的NW向次级断裂带控制了另一深部含水岩溶发育区,不同方向的含水岩溶发育区因断裂构造相通,呈现“网络”式的分布格局。  相似文献   

18.
Abstract

In this paper we concentrate particularly on the geomorphological indicators left by active tectonics. In the central foothills of Taiwan, we used topography, drainage pattern and structural data to perform quantitative morphometric analysis and to determine relative age of fault-related anticlines. The Tiehchen, Tatu and Pakua ridge belt is a fault-related anticline system located in the hanging wall of the Changhua fault along the western thrust front of the foothills. Geomorphic systems are analysed with intent to detect the various responses of landforms and drainage pattern to late Quaternary deformation. Topography and drainage basin register uplift and are valuable tools to discriminate lateral propagation of an active frontal fold. Geomorphic field evidence and quantitative morphometric parameters are used to define the evolution of the rising anticline ridges and to infer tectonism style along an active front. Geometry of alluvial fans, formed along the frontal side of the anticlines, and weathered terrace deposits provide relevant information on neotectonics. Knowledge concerning these younger anticline ridges, makes this area a good example of an actively forming mountain front. We discuss in detail the origin of N045°, N095 and N120° trending oblique fault scarps which delimite numerous fault blocks. The fault scarps morphology is characterized by imbricate talus facets. Steeper topography accompanied by breaks in the slope along some transverse profiles, seems to correspond to the traces of successive uplifts. © 2001 Éditions scientifiques et médicales Elsevier SAS  相似文献   

19.
喀斯特断陷盆地环境地质分区及功能   总被引：9，自引：6，他引：3  
喀斯特断陷盆地是随着新生代高原隆升产生的断裂活动所引起的断块差异沉陷及溶蚀作用共同形成的山间盆地。由其以局部地块断陷为主导并伴随侵蚀及溶蚀的成因机制所决定,具有地貌分区明显、新构造运动强烈、水资源分布不均、土壤植被分带性强、气候垂向变化明显、人类活动区间差异大等特征。其中,地貌形态—成因类型既是地质环境本质特征的综合反映,又是对生境具有重大影响的自然因素,而且容易认识和识别,是环境地质分区的良好标志。以地貌形态—成因类型为标志,喀斯特断陷盆地可划分为侵溶蚀山区、溶蚀丘峰谷地区、沉积平坝区、侵溶蚀河谷区4个环境地质分区。侵溶蚀山区生态功能突出,溶蚀丘峰谷地区生态与经济功能并重,沉积平坝区经济功能尤显重要,侵蚀河谷区视所处大江大河流域的区位及宏观影响而定。资源开发和环境恢复治理,应与环境地质分区功能相协调,按流域系统评价和全面权衡利弊、科学规划布局,才能取得可持续的成效。   相似文献   

20.
As part of a larger regional research program “KarstEAU”, the authors have applied electrical resistivity tomography (ERT) techniques to characterize heterogeneities in the Port-Miou coastal karst aquifer (Cassis, SE France). Field surveys were carried out on intensely fractured and karstified Urgonian carbonates. Extensive research has characterized macro- and micro-scale geology of the Port-Miou area and particularly underground water-filled conduits and fault/fracture and karst systems within a former quarry. The authors applied 2D ERT along two surface profiles of length 420 and 595 m to test capability for delineating subsurface conduits and possibly relationship between conduit and fault/fracture/karst orientation; and 3D ERT with a dense 120 electrode array at 1 m spacing (11 × 10 m) was applied over an area of the quarry that had been profiled using 3D georadar and which has had intensive nearby structural geological interpretation. The 2D profiling imaged several underground conduits at depths to >50 m below ground surface and below sea level, including possibly the main Port Miou submarine spring and smaller springs. The 2D profiling within the quarry provided a better understanding of the connectivity between major fractures and faults on the quarry walls and secondary springs along the coast supporting flow of the secondary springs along interpreted fracture orientations. In addition, 2D inversion-derived conductivity models indicate that high resistivity zones above sea-level are associated with non-saturated zones and low resistivity anomalies in the non-saturated zone are associated with residual clays in paleokarsts. A partitioned lower resistivity zone below sea-level can be associated with a higher porosity/permeability zone with fractures and karstic features. Inversion models of the dense 3D ERT data indicate a higher resistivity volume within the larger surveyed block. The survey characterized the non-saturated zone and the ERT resistivities are correlated with karst features interpreted by 3D georadar and visible in the inferior wall of the quarry.  相似文献   

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