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1.
Maximiliano J. Bezada Michael Schmitz María Ins Jcome Josmat Rodríguez Franck Audemard Carlos Izarra the BOLIVAR Active Seismic Working Group 《Journal of Geodynamics》2008,45(4-5):191-200
The Falcón Basin in northwestern Venezuela has a complex geological history driven by the interactions between the South American and Caribbean plates. Igneous intrusive bodies that outcrop along the axis of the basin have been associated with crustal thinning, and gravity modeling has shown evidence for a significantly thinned crust beneath the basin. In this study, crustal scale seismic refraction/wide-angle reflection data derived from onshore/offshore active seismic experiments are interpreted and forward-modeled to generate a P-wave velocity model for a 450 km long profile. The final model shows thinning of the crust beneath the Falcón Basin where depth to Moho decreases to 27 km from a value of 40 km about 100 km to the south. A deeper reflected phase on the offshore section is interpreted to be derived from the downgoing Caribbean slab. Velocity values were converted to density and the resulting gravimetric response was shown to be consistent with the regional gravity anomaly. The crustal thinning proposed here supports a rift origin for the Falcón Basin. 相似文献
2.
The crust and upper mantle discontinuity structure beneath Alaska inferred from receiver functions 总被引：1，自引：0，他引：1
Yinshuang Ai Dapeng Zhao Xing Gao Weiwei Xu 《Physics of the Earth and Planetary Interiors》2005,150(4):339-350
In this study, three receiver function stacking methods are used to study the detailed crust and upper mantle structure beneath south-central Alaska. We used teleseismic waveform data recorded by 36 stations in the Broadband Experiment Across the Alaska Range (BEAAR) and 4 permanent stations in Alaska. H − κ stacking method using P-to-S converted wave and its multiply reflected waves between the Earth's surface and the Moho discontinuity is adopted to estimate the crustal thickness (H) and average crustal VP/VS ratio (κ) in this region. The receiver function results for 24 stations show that the crustal thickness under Alaska ranges from 26.0 to 42.6 km with an average value of 33.8 km, and the VP/VS ratio varies from 1.66 to 1.94 with an average value of 1.81 which corresponds to an average Poisson's ratio of 0.277 with a range from 0.216 to 0.320. High Poisson's ratios under some stations are possibly caused by partial melting in the crust and the uppermost mantle. Common converted point (CCP) stacking results of receiver functions along three lines show clear Moho and slab images under this subduction zone. The depths of the slab from our CCP stacking images are consistent with those estimated from the Wadati–Benioff Zone (WBZ). In the area between two stations DH2 (147.8°W, 63.3°N) and DH3 (147.1°W, 63.0°N), a Moho depth offset of about 10 km is found by both the H − κ and CCP stacking techniques. Common depth point (CDP) stacking of receiver functions shows not only the 410-, 520- and 660-km discontinuities, but also significant variations (−30 to 15 km) in the transition zone thickness under the southwest and southeast parts of the study region. The transition zone becomes thinner by 20–30 km, indicating that the temperature there is 150–200 K higher than that of the normal mantle. 相似文献
3.
M. Tahara K. Uehira H. Shimizu M. Nakada T. Yamada K. Mochizuki M. Shinohara M. Nishino R. Hino H. Yakiwara H. Miyamachi K. Umakoshi M. Goda N. Matsuwo T. Kanazawa 《Physics of the Earth and Planetary Interiors》2008,167(1-2):19-33
The Hyuganada region, a forearc region of Southwest Japan, is characterized by several interesting geological and geophysical features, i.e., significant aseismic crustal uplift of 120 m during the past 120 thousand years at the Miyazaki Plain, negative free-air gravity anomalies with the maximum magnitude of −130 mgal, and relatively less cohesive interplate coupling compared with that for off the Shikoku and Kii Peninsula. In order to examine the causes of these observations, we determined a detailed three-dimensional seismic velocity structure based on the seismic data observed by ocean bottom seismometers (OBS) and land stations. P- and S-wave tomographic velocity structures clearly indicate the subducting slab and also the zones of high Poisson's ratio at 25–35 km depth along the coastline of the northeastern part of the Hyuganada. The region with high Poisson's ratio may correspond to the serpentinized mantle wedge as suggested for other mantle wedges, and appears to be coincident with the zone for observed aseismic slips such as the slow-slip and after-slip events. Also, the detection may be related to a relatively weak interplate coupling in the Hyuganada region. The tomographic structures also indicate low velocity zones with a horizontal scale comparable to the Kyushu-Palau Ridge in and around the subducting slab. If we assume that the low velocity zones correspond to the subducted Kyushu-Palau Ridge, then the predicted gravity anomaly due to the density contrast between the low velocity zones and the surrounding region can explain about 60% of the gravity anomaly in the Hyuganada region. The buoyancy is probably an important factor for the crustal uplift observed in the Miyazaki Plain, the steep bending of the subducting slab and the normal fault-type earthquakes around the Hyuganada region. 相似文献
4.
Walter S. Kiefer 《Earth and Planetary Science Letters》2004,222(2):349-361
Syrtis Major is an ancient basaltic shield volcano on Mars with a basal diameter of 1100 km. The free-air gravity anomaly is 126 mGal at spherical harmonic degree 50 and reaches its maximum amplitude over the 2 km deep topographic caldera. The observed gravity anomaly cannot be explained by flexurally supported surface topography and requires the presence of a buried, high-density load. The geologically most reasonable interpretation of this high-density load is that it represents the magma chamber of Syrtis Major, now solidified and filled at least in part by dense igneous cumulates. Pyroxene is likely to be the dominant cumulate mineral in this system, although olivine may also be present. Gravity models presented here define the structure of the buried load and in essence provide a look at the magmatic plumbing system of this volcano. The preferred model involves a buried load that is approximately 300×600 km across, roughly twice as large as the topographic caldera. Both the buried load and the caldera are elongated in the north-south direction. In the center of the buried load, the minimum thickness is 2.8 km for an olivine-dominated cumulate system or 3.9 km for a pyroxene-dominated system. The best terrestrial analog for this structure is the Bushveld Complex, an igneous cumulate body that is similar in size and thickness to the Syrtis Major structure. Assuming that the mean crustal density is 2600 kg m−3 due to impact brecciation, the elastic lithosphere at Syrtis Major was 10-15 km thick at the time when the topographic load was emplaced. This corresponds to a lithospheric thermal gradient of 28-52 K/km and a surface heat flux of 70-130 mW m−2. Higher resolution gravity data, such as that which is planned for the 2005 Mars Reconnaissance Orbiter, will permit further refinement of the dimensions of this structure. 相似文献
5.
从Global CMT目录搜集了1976年1月至2016年6月之间的震源深度大于70km的255个震源机制解,用阻尼应力反演方法,分70～160km和170～310km两个深度,计算了帕米尔—兴都库什地区的构造应力场;同时以10km为间隔计算了兴都库什地区深度介于70～310km之间的应力形因子.得到以下初步结论:兴都库什板片向下俯冲和帕米尔地区断裂带的横向拉张,可能是导致应力场不同的原因.兴都库什俯冲带与帕米尔俯冲带碰撞,导致交汇地区(37°N—37.5°N)的应力场参数突变.兴都库什俯冲板片受到深部温度、压力等因素,出现薄弱面进而形成拆离板片.其脱离了主俯冲板片的束缚后,重力的上下拉张作用导致空区附近张轴倾伏角接近90°,拆离板片俯冲至上地幔不连续面,导致板片部分熔融进而应力形因子随着深度变小.而拆离板片受到地幔挤压其内部发生破碎,其压应力轴由西部的NS到东部NW-SE方向偏转及纵向张应力轴倾伏角变小. 相似文献
6.
M. Muoz H. Fournier M. Mamani J. Febrer E. Borzotta A. Maidana 《Physics of the Earth and Planetary Interiors》1990,60(1-4):195-211
The first magnetotelluric deep soundings in Chile were carried out during 1986 in the Villarrica active volcano zone (39°25′S, 71°57′W). In the TM mode of polarization, the curves show a distorted segment with dispersion. A static distortion at long periods is observed in curves in the TE mode of polarization; the segment was shifted vertically to fit the geomagnetic global model values at daily periods. This modified curve was used for 1D modelling to determine the electrical structure in the study area. The upper level of the intermediate conducting layer of resistivity 20–60 ω m is found to be at 35–50 km depth. A higher resistivity layer (600 ω m), starting at 100 km depth, may be resolved in the intermediate conducting layer. A sharp decrease in the resistivity is shown by the model at 500 km.
Large heterogeneities at the level of the conducting layer encountered in the 1D modelling, and increased resistivity of the ultimate layer, may account for distortion observed at long periods. Two-dimensional test models show that the conducting layer in the area of Villarrica volcano may be an anomalous heated layer surrounded by rocks of higher resistivity of about 2 × 103 ω m. These features correspond to the interaction with a subsiding oceanic lithosphere resulting in a complex thermal structure and perturbed resistivity distribution in transition zones of the Pacific type such as Chile, and to the existence of a megafault and a system of fractures in the sounding area. These facts make it difficult to determine the conductance of the electrical asthenosphere.
The parameters of the model structure correlate well with geophysical and geochemical results obtained in the area by other workers. Gravity studies indicate a maximum crustal thickness of about 37 km, which implies a non-full compensation according to the Airy hypothesis. The morphology of the Wadati-Benioff zone clearly shows a sharp decrease of earthquake foci at 50 km depth, and a reinitiation of seismic activity from a depth of 100 km down to 160 km. Kaufman and Keller and Levi and Lysak empirical relationships between heat flow and thickness of the lithosphere are somewhat consistent when the parameters of the model structure are assumed. The strontium isotope ratios are indicative of minimal crustal contamination of mantle-derived magmas, thus allowing a relatively thin crust under the area. Furthermore, the SB index of partial melting of mantle peridotite may suggest the contribution of uprising material from the deep asthenosphere through fractures extending to depth. 相似文献
7.
跨越中、印、缅三国交界的青藏高原东南的喜玛拉雅“东构造结”地区（92°E~97°E，26°N~30°N）一半以上的面积尚没有重力测点，是重力数据空白区,故无法直接研究其重力场特征与深部地壳结构（构造）.本文分析了卫星重力异常的特性，提出应用卫星重力异常作为近似空间重力异常，并作布格改正后，得到的布格重力异常具有与该地区地形高程呈镜像相关的特征，可用以研究深部地壳结构.据三条重力剖面计算得到该地区三个地壳深部结构剖面的结果，给出青藏高原地壳厚度>70 km；喜马拉雅造山带为55 km左右；布拉马普特拉河谷盆地为33~35 km；那加山山脉地区为40~45 km，显示出三者为三个不同的构造单元.同时给出布拉马普特拉构造单元为相对高密度的刚性物质构成，随着印度洋板块向北运移，在碰撞、挤压下，插入青藏高原东南缘一带.导致该地带的强烈构造运动，和频发大、小地震.最后提出了几点认识和建议. 相似文献
8.
Jeroen van Hunen Arie P van den Berg Nico J Vlaar 《Earth and Planetary Science Letters》2001,190(3-4):125-135
Very low to zero shallow dip angles are observed at several moderately young subduction zones with an active trenchward moving overriding plate. We have investigated the effects of latent heat for this situation, where mantle material is pushed through the major mantle phase transitions during shallow low-angle subduction below the overriding plate. The significance of the buoyancy forces, arising from the latent heat effects, on the dynamics of the shallowly subducting slab is examined by numerical modeling. When a 32-Ma-old slab is overridden with 2.5 cm/yr by a continent, flat subduction occurs with a 4–5 cm/yr convergence rate. When latent heat is included in the model, forced downwellings cause a thermal anomaly and consequently thermal and phase buoyancy forces. Under these circumstances, the flat slab segment subducts horizontally about 350 km further and for about 11 Ma longer than in the case without latent heat, before it breaks through the 400-km phase transition. The style of subduction strongly depends on the mantle rheology: increasing the mantle viscosity by one order of magnitude can change the style of subduction from steep to shallow. Similarly, an overriding velocity of less than 1 cm/yr leads to steep subduction, which gradually changes to flat subduction when increasing the overriding velocity. However, these model parameters do not change the aforementioned effect of the latent heat, provided that low-angle subduction occurs. In all models latent heat resulted in a substantial increase of the flat slab length by 300–400 km. Varying the olivine–spinel transition Clapeyron slope γ from 1 to 6 MPa/K reveals a roughly linear relation between γ and the horizontal length of the slab. Based on these results, we conclude that buoyancy forces due to latent heat of phase transitions play an important role in low-angle subduction below an overriding plate. 相似文献
9.
A summary of results based mainly on the inversion of available surface-wave dispersion data is given for the Mediterranean area both for crustal and upper mantle structure. The results are presented on maps outlining the regionalization of the crust and the lithosphere-asthenosphere system in the area. It is possible to distinguish several types of crust with average S-wave velocities in the range 2.8–3.8 km s−1 and thickness varying from a minimum of about 10–16 km, in the Western Mediterranean, to a maximum of about 50 km (including a possible transitional layer) beneath the Ionian Sea. The average properties of the crust and of the lithospheric part of the mantle indicate a possible continuous structure extending from North Africa through the Ionian Sea to the Adriatic Sea, characterized by the presence of a transitional layer at the crust-mantle boundary. Strong lateral variations are present in the lithosphere-asthenosphere system both in thickness, from 30 km in the Western Mediterranean, to about 130 km, under the Alps, and in S-wave velocity, from 4.1–4.2 km s−1 up to 4.7 km s−1. The relatively high position of low resistivity material that seems to characterize the Mediterranean area agrees fairly well with the shallower average top of the asthenosphere found in this area from the study of the elastic properties. The usefulness of combining seismological and electromagnetic studies is stressed. 相似文献
10.
在喜马拉雅造山带的东缘,雅鲁藏布江缝合带在这里发生急剧转折,南迦巴瓦变质体快速隆起,然而关于东构造结的形成机制一直未有定论.利用围绕南迦巴瓦峰的48个宽频带地震台站记录的远震数据提取P波接收函数,采用改进的H-κ叠加方法和共转换点叠加方法综合研究了东构造结的地壳厚度、波速比分布和地壳结构特征.结果表明:研究区平均地壳厚度为64.03 km,大部分台站介于60.48~66.55 km范围;平均波速比为1.728,主要集中范围为1.696~1.742.东构造结地壳厚度横向变化剧烈,构造结西端和北端厚而中间薄,东构造结核部Moho面呈现上隆的构造形态,东西向上隆幅度约为6~7 km,南北向的上隆超过9~10 km.东构造结核部地壳上隆减薄可能由高密度、高波速的岩石圈撕裂残片拆沉到上地幔软流圈后重力失衡所致.平均波速比超过1.8的高值异常展布于东构造结的两侧,推测为环东构造结的壳内部分熔融体.东构造结地壳上隆减薄和壳内部分熔融的存在很可能均与幔源热物质的上涌有关,而软流圈地幔的上涌则可能由印度板片的撕裂引起. 相似文献
11.
松辽盆地作为东亚裂谷系的一部分,与华北克拉通一起经历了中生代岩石圈减薄的重大地质事件.对大陆岩石圈-软流圈状态和构造的整体认识,是研究大陆岩石圈减薄深部动力学过程的关键.在获得过松辽盆地的106个宽频和30个长周期大地电磁测深数据的基础上,完成测点数据二维偏离度、构造走向等计算与分析,进一步采用非线性共轭梯度算法,对TE和TM模式数据进行二维联合反演,获得了沿剖面的壳-幔电性结构,并依此构建了松辽盆地壳-幔结构模型.研究结果表明：（1）大兴安岭地区岩石圈厚度约为160 km,松辽盆地岩石圈厚度约为45 km,张广才岭岩石圈厚度在70~100 km之间,莫霍面与岩石圈底界面不呈镜像关系.软流圈整体表现为中、低阻异常,电阻率值在30 Ωm左右,其形态呈西倾约30°的蘑菇状异常,指示了软流圈物质上涌的形式,有别于软流圈垂直上涌的传统认识.（2）松辽盆地深部存在双层高导异常（电阻率小于5 Ωm）,上层为壳内高导层,呈"蛇"状分布,推断为岩浆底侵区,下层为幔内高导层,呈"哑铃"状,为软流圈上涌区.软流圈内存在两个"哑铃"状中、高阻异常,推断为拆沉的岩石圈地幔.具有冷的、高密度的下降物质流的堆积以及拆沉块体下插到两侧山岭是促使大兴安岭与张广才岭在中生代伸展环境中快速隆升重要原因;（3）松辽盆地经历了岩石圈减薄事件,与大兴安岭岩石圈厚度相比,松辽盆地岩石圈厚度减薄了近100 km,与东侧张广才岭相比减薄了70 km,而与中生代华北地台100 km的岩石圈厚度相比,减薄了近50 km,其经历了岩石圈伸展期、裂解期、拆沉期和增长期的动力学过程. 相似文献
12.
本文简介从新疆叶城至西藏狮泉河的大地电磁测深剖面．它北起塔里木盆地，横跨昆仑山脉和喀喇昆仑山脉地区到冈底斯西段，全长８００余公里．探测结果表明，不同测点的地壳内部有的有两个低阻层，有的则只有一个低阻层，壳内第１低阻层的埋藏深度约１０－３５ｋｍ，第２低阻层的埋藏深度约３０－６５ｋｍ。在南昆仑缝合带以南，壳内低阻层的埋藏深度有从南向北不断加深的趋势；而在其以北的壳内低阻层的埋藏深度则与此相反．上地幔第１低阻层的埋藏深度约在１００－１５０ｋｍ之间，第２低阻层的埋藏深度约在３５０－５５０ｋｍ之间． 相似文献
13.
Mohan L. Gupta 《Journal of Volcanology and Geothermal Research》1981,10(4):279-292
Heat flow values from some additional locations in the Cenozoic Cambay Basin have been determined. Together with the previously published data, they show that the heat flow is moderate (55–67 mW/m′) in the southern part of the basin towards Broach and Ankleswar, and that there is a clear trend of high heat flow (75–93 mW/m2; range of average values for six different, widely separated, locations) in a part of the basin located north of the Mahisagan river between Cambay and Mehsana along a stretch of about 140 km. Conductive steady state geotherms, calculated using observed high surface heat flow values and appropriate models show, beneath the Cambay-Mehsana area, a large degree of melting in the lower crust and upper mantle, which is not suggested by the existing geodata. Considering this aspect and taking into account the existence of a normal crust about 37 km thick below the Cambay-Tarapur and Ahmedabad-Mehsana blocks (as obtained from deep seismic soundings), it has been inferred that the heat flow anomaly is due to transient thermal perturbations introduced from tectonic activity in the form of magmatic intrusions. A careful analysis of heat flow, gravity and other related geodata point out and support the possibility of a Miocene/Pliocene basic intrusive body at a depth of around 10 km under the Cambay-Mehsana area. Further, the consistent trend of the thermal and gravity fields indicates thinning of the postulated intrusive body from Cambay towards Mehsana. 相似文献
14.
Imbrication, indicating flow and source direction, occurs in three Pleistocene or upper Pliocene pumice-flow tuffs exposed in a 700-km2 area on the east flank of the Cascade Range near Bend, Oregon, and shows the location of previously unknown source vents of these tuffs. The imbrication is formed by inclined elongate and/or flat pumice or lithic fragments and locally by elongate plagioclase crystals. Imbrication is best developed within the lower zones of individual flow units; the pumiceous top zones also locally show imbrication directions parallel to that in the lower zones. Moreover, the areal pattern of size distribution of lithic and pumice fragments in the flows is concordant with the flow direction pattern indicated by imbrication.The upper pumice flow shows a fan-shaped pattern of flow directions indicated by imbrication which points to a western source. A possible vent, about 20 km west of Bend in the highland near Broken Top Volcano, is marked by many silicic domes and basaltic cinder cones where there is a 6–8 mgal negative Bouguer gravity anomaly. In contrast, imbrication in the middle and lower pumice flows indicates flow from a source southwest of Bend. Vents in this direction are not obvious. Possible buried vents are located about 30 km and 45 km southwest of Bend near Sitkum Butte and Lookout Mountain, respectively. 相似文献
15.
Daria Zandomeneghi Javier Almendros Jesús M. Ibez Gilberto Saccorotti 《Physics of the Earth and Planetary Interiors》2008,167(1-2):8-18
We determine the three-dimensional distribution of P- and S-wave velocities for Central São Miguel Island (Azores, Portugal) by tomographic inversion of local earthquake arrival times. We use P- and S-phases from 289 earthquakes recorded by a network of 20 seismometers. The model shows good resolution in the shallowest 5–6 km, as illustrated by different resolution tests. There are several velocity anomalies, interpreted as pyroclastic deposits, intrusive bodies, geothermal fields, and the effects of tectonics. A low Vp zone marks Furnas caldera, probably evidencing volcaniclastic sediments with development of intense geothermal activity. Another low Vp zone extends in correspondence of the highly fractured area between Fogo and the north coast. Conversely, strong positive anomalies are found south of Fogo and northwest of Furnas. They are interpreted in terms of high-density deposits and remnants of a plutonic intrusion. These interpretations are supported by the distribution of Vp/Vs, and are consistent with previous geological, geochemical, and geophysical data. 相似文献
16.
帕米尔高原是五大山脉汇结之中心,被称为"西构造结".在此山高耸谷陡深是人迹罕至的无人区.应用稀少的地面重力和人工地震数据和卫星重力资料,以NNW和NEE向两条长达1620 km的十字交叉剖面,对帕米尔高原地区地壳深部结构与区域地质构造进行了研讨.帕米尔高原中心地区地壳厚度(莫霍界面深度)接近70 km,并在总体上呈向四周逐渐延展减薄(变浅)的总趋势,到帕米尔的周边地区减薄为50余km左右.这里是一个壳幔结构变异的构造强烈活动地域. 相似文献
17.
南海东北部首次成功实施海陆联合深地震探测,填补了海陆过渡带深地震探测的空白. 利用该次海陆联测地震数据,通过数据处理、震相分析、射线追踪、走时模拟等方法,获得了滨海断裂带附近的纵波地壳速度结构,探明了海陆联测剖面中滨海断裂带可能位置. 地壳速度结构为陆壳结构,地壳厚度由陆地向海区逐步变薄;在上地壳下部普遍存在一层速度为5.5～5.9km·s-1、厚度为2.5～4.0km的低速层,并向海区方向减薄,该区未发现明显的高速层. 滨海断裂带为一纵向低速带,位于南澳台东南35km处,对应于重、磁异常带,断裂带断至莫霍面,是华南陆区正常型陆壳与海区减薄型陆壳的分界地壳断裂. 相似文献
18.
1303年在山西洪洞附近发生的8级巨大地震, 是中国根据现存较为详细的文献记载史料所确定的最早的一次8级地震。 这次地震距今已有700多年的历史, 而地震所在区域至今仍有持续不断的小地震活动。 本文根据地震破裂区1981年至2013年的中小地震精定位地震目录, 采用震源断层面拟合方法, 反演得到了1303年山西洪洞地震的震源断层面参数: 走向19.3°、 倾角88.5°、 滑动角-170.0°。 断层面长75.5 km, 宽26.2 km, 深度为地下11.12 ～37.35 km。 将地震破裂区的地震精确定位资料以近东西向的洪洞断裂为界划分为地震北段和地震南段, 分段进行地震震源断层拟合, 反演得到洪洞地震北段震源断层面参数: 走向13.7°、 倾角76.6°、 滑动角-157.6°。 断层面长32.7 km, 宽21.7 km, 深度为地下11.97～32.86 km; 南段震源断层面参数: 走向20.3°、 倾角87.1°、 滑动角-154.6°。 断层面长45.9 km, 宽16.6 km, 深度为地下9.32 km～25.50 km。 无论是分段还是不分段, 反演得到的洪洞地震震源断层均是右倾的近直立断层, 属于右旋走向滑动性质。 分段计算得到的地震北段震源断层深度比南段更深, 将反演得到的震源断层与临汾盆地深部构造最新研究成果进行了分析对比, 北段震源断层深度及倾角大小与深地震剖面推测得到的深大断裂几乎相同。 震源断层在地表的投影与洪洞地震的高烈度区能够较好地对应。 相似文献
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用射线分布分析法对伽师强震群区的高分辨折射地震剖面资料进行了更进一步的分析处理， 得到了伽师强震群区更完整的基底界面结构特征. 结果表明，在伽师强震群区地壳上部存在两个明显的结构界面:第一个界面的结构连续、完整，其埋深变化不大， 在2.6～3.3 km之间，为一向天山方向逐渐抬升、 近平直的倾斜界面；第二个界面的埋深变化较大， 在8.5～11.8 km之间，为古老的塔里木盆地结晶基底. 在约37 km桩号附近结晶基底有近2.5 km的深度突变， 推断可能是伽师强震群区超基底断裂所致. 以该断裂为界，结晶基底分为西南、东北两段. 每段内界面的埋深变化不大， 西南段的埋深约11.5 km， 东北段的埋深约为8.5～9.0 km，该段在从西南向东北整体抬升的背景上略有上隆，反映出在塔里木地块西北缘特殊的构造环境下上部地壳的变形特征. 相似文献
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通过对鲁西隆起区重磁资料的分析和反演计算,研究了沂沭断裂带、齐河—广饶断裂带、聊城—兰考断裂带、丰沛断裂带以及地块内部断裂的重磁异常、莫霍面和居里面深度特征,并讨论了鲁西隆起的地质构造特征和构造活动性.结果显示:鲁西隆起基底广泛出露,沉积层主要分布在由断裂下降盘控制的凹陷内,区内断裂深度达20 km以上,其中蒙山断裂深入至上地幔,控制了蒙山金伯利岩型金刚石矿的产出;鲁西隆起区莫霍面深度为30—35 km,整体呈向西开口的箕形,地块中部地壳厚度较厚,除西侧地壳呈阶梯状增厚外隆起地块四周地壳逐渐减薄;居里面深度介于20—33 km之间,中部地区较深,为整体稳定的地块,断裂带分布位置对应于居里面梯度带;地震活动主要集中于断裂带与莫霍面梯度带交会区以及断裂带上的居里面突变区. 相似文献