构造活动地区工程构造稳定性研究     

刘行松  钟嘉猷 《工程地质学报》1995,3(1):1-9

拟建的新疆喀拉喀什河乌鲁瓦提水电站位于现代地壳运动十分活跃的区域。野外证据显示出，坝区的Ｆ＿（１２）断层新活动延续到晚更新世，电站附近的石门北断层在第四纪有活动。对采自坝区及附近几条断层的断层物质样品进行了变形显微构造、石英颗粒表面形貌和微结构类型、ＴＬ年龄的分析测定，结果表明，Ｆ＿（１２）最新活动的上限时间不晚于３万年，Ｆ＿（３０）和石门断层的活动持续到晚更新世，石门北断层最新的活动的上限时间约２万年。根据区域断裂的分布和应力场的情况，进行了构造模拟实验，预测出工程区在区域应力场的继续作用下，应力集中在远离坝址的部位，坝址附近不会出现新的应力集中点。总体看，所选坝址是地壳活动区中相对较稳定的地段。  相似文献   

粘滑失稳及其物理场时空分布的实验研究   总被引：6，自引：3，他引：6  

邓志辉  马胜利 《地震地质》1995,17(4):305-310

摩擦滑动的物理场实验研究表明：（１）能量空间分布的差异是失稳的重要条件，单发型大事件常发生于高能量向低能量的突变带或高能量背景区内的相对低能量区；（２）单发型大事件的孕育过程常常经历若干个能量输入输出循环，产生多个前兆阶段，并在失稳前源区常有一个弱化过程。小震或群发型事件失稳前常常只有一个能量积累与强化的过程，失稳前兆阶段性反映较差；（３）粘滑失稳时断层的位错与声发射的大小未见明显关系  相似文献   

则木河断裂的现今活动方式及其地形变鉴别标志探讨   总被引：2，自引：0，他引：2  

张崇立  任金卫 《地震地质》1995,17(4):427-431

根据地壳形变测量资料，探讨了则木河断裂的现今活动方式及其定性的地形变鉴别标志问题。结果表明：则木河断裂的现今活动具有明显的分段性特征，即以大箐为界分为南北两段，北段以粘滑活动为主，南段以蠕滑活动为主；沿则木河断裂带垂直位移速率空间分布特征的显著差异，可以作为鉴别断裂现今活动方式的标志之一，其位移速率的相对大小，可作为鉴别断裂现今活动方式的一种参考标志  相似文献   

大灰厂跨断层形变资料的地震信息识别   总被引：1，自引：0，他引：1  

李志雄  吴邦素 《地震》1995,(3):222-227

利用具有明显物理意义的断层蠕动模型在充分考虑可能存在的干扰因素影响的基础上，对大灰石台跨断层地形变资料在１９８９年大同地震前后出现的较大幅度变化进行了异常属性分析。结果表明，这个时期的异常变化尽管叠加有一定的降雨影响，但蠕动模型计算得出的地表变化理论值与实际变化有一定程度的符合，显示出在区域应力场作用下，八宝山断层局部地段在大同地震前后可能存在着与区域应力场应力增强及应力调理有关的构造活动。  相似文献   

Constitutive relations for fault slip and earthquake instabilities   总被引：1，自引：0，他引：1  

James R. Rice 《Pure and Applied Geophysics》1983,121(3):443-475

Constitutive relations for fault slip are described and adopted as a basis for analyzing slip motion and its instability in the form of earthquakes on crustal faults. The constitutive relations discussed include simple rate-independent slip-weakening models, in which shear strength degrades with ongoing slip to a residual frictional strength, and also more realistic but as yet less extensively applied slip-rate and surface-state-dependent relations. For the latter the state of the surface is characterized by one or more variables that evolve with ongoing slip, seeking values consistent with the current slip rate. Models of crustal faults range from simple, single-degree-of-freedom spring-slider systems to more complex continuous systems that incorporate nonuniform slip and locked patches on faults of depth-dependent constitutive properties within elastic lithospheric plates that may be coupled to a viscoelastic asthenosphere. Most progress for the rate and state-dependent constitutive relations is at present limited to single-degree-of-freedom systems. Results for stable and unstable slip with the various constitutive models are summarized. Instability conditions are compared for spatially uniform versus nonuniform slip, including the elastic — brittle crack limit of the nonuniform mode. Inferences of constitutive and fracture parameters are discussed, based on earthquake data for large ruptures that begin with slip at depth, concentrating stress on locked regions within a brittle upper crust. Results of nonlinear stability theory, including regimes of complex sustained stress and slip rate oscillations, are outlined for rate and state-dependent constitutive relations, and the manner in which these allow phenomena like time-dependent failure, restrengthening in nearly stationary contact, and weakening in rapidly accelerated slip, is discussed.  相似文献   

永平水泄铜钴矿控矿因素     

杨宏城 《云南地质》2007,26(4):416-420

水泄铜钴矿区地质条件较为复杂,控矿因素较多,通过分析认为主要受断层及岩性控制,地层初始富集,构造及区域变质作用提供通道及热源。水的循环、溶解作用形成热卤水成矿。  相似文献   

Fault induced permanent ground deformations: Experimental verification of wet and dry soil, numerical findings’ relation to field observations of tunnel damage and implications for design     

Jrgen Johansson  Kazuo Konagai 《Soil Dynamics and Earthquake Engineering》2007,27(10):938-956

Few building codes contains provisions fault surface ruptures and accompanying soil deformations which constitutes a great risk to human lives, buildings and infrastructure. A numerical and experimental comparison show a fair agreement of result. Analysis of “real” scale show the how water increases the incompressibility of wet soil causing shear deformations to become larger and conjugate ruptures to appear for reverse faults. Field observations and numerical analysis indicates that horizontal compression of soil surrounding underground structures should be taken into account in design.  相似文献   

A new fault rupture scenario for the 2003 M_w 6.6 Bam earthquake, SE Iran: Insights from the high-resolution QuickBird imagery and field observations     

Bihong Fu  Xinglin Lei  Khaled Hessami  Yoshiki Ninomiya  Takashi Azuma  Hisao Kondo 《Journal of Geodynamics》2007,44(3-5):160-172

The December 26, 2003 M_w 6.6 Bam earthquake is one of the most disastrous earthquakes in Iran. QuickBird panchromatic and multispectral satellite imagery with 61 cm and 2.4 m ground resolution, respectively provide new insights into the surface rupturing process associated with this earthquake. The results indicate that this earthquake produced a 2–5 km-wide surface rupture zone with a complex geometric pattern. A 10-km-long surface rupture zone developed along the pre-existing Bam fault trace. Two additional surface rupture zones, each 2–5 km long, are oblique to the pre-existing Bam fault in angles of 20–35°. An analysis of geometric and geomorphic features also shows that movement on the Bam fault is mainly right-lateral motion with some compressional component. This interpretation is consistent with field investigations, analysis of aftershocks as well as teleseismic inversion. Therefore, we suggest that the 2003 Bam earthquake occurred on the Bam fault, and that the surface ruptures oblique to the Bam fault are caused by secondary faulting such as synthetic shears (Reidel shears). Our fault model for the Bam earthquake provides a new tectonic scenario for explaining complex surface deformations associated with the Bam earthquake.  相似文献   

Geology and hazard implications of the Maraunot notch in the Pinatubo Caldera,Philippines     

A. M. F. Lagmay  K. S. Rodolfo  F. P. Siringan  H. Uy  C. Remotigue  P. Zamora  M. Lapus  R. Rodolfo  J. Ong 《Bulletin of Volcanology》2007,69(7):797-809

The 1991 Pinatubo eruption left 5–6 km³ of debris on the volcano slopes, much of which has been mobilized into large lahars in the following rainy seasons. Also during the eruption, collapse, localized in part along preexisting faults, left a caldera 2.5 km in diameter that almost immediately began to accumulate a 1.6 × 10⁸ m³ lake. By 2001, the water had risen to the fault-controlled Maraunot Notch, the lowest, northwestern portion of the caldera rim comprising the physiographic sill of the Caldera Lake. That year, a narrow artificial canal dug into an old volcanic breccia underlying the outlet channel failed to induce a deliberate lake breakout, but discharge from heavy rains in July 2002 rapidly deepened the notch by 23 m, releasing an estimated 6.5 × 10⁷ m³ of lake water that bulked up into lahars with a volume well in excess of 1.6 × 10⁸ m³. Lakes in other volcanoes have experienced multiple breakouts, providing practical motivation for this study. Fieldwork and high-resolution digital elevation models reveal andesites and ancient lacustrine deposits, strongly fractured and deformed along a segment of the Maraunot Fault, a prominent, steeply dipping, left-lateral fault zone that trends N35°–40°W within and parallel to the notch. Seismicity in 1991 demonstrated that the Maraunot Fault is still active. The fault zone appears to have previously been the erosional locus for a large channel, filled with avalanche or landslide deposits of an earlier eruption that were exhumed by the 2002 breakout floods. The deformed lacustrine sediments, with an uncalibrated ¹⁴C age of 14,760 ± 40 year BP from a single charcoal sample, attest to the existence of an earlier lake, possibly within the Tayawan Caldera, rim remnants of which survive as arcuate escarpments. That lake may well have experienced one or more ancient breakouts as well. The 2002 event greatly reduced the possibility of another such event by scouring away the erodible breccia, leaving less erodible fractured andesites and lacustrine rocks, and by enlarging the outlet channel and its discharge capacity. Several lines of evidence indicate, however, that future lahar-generating lake breakouts at the notch may keep populations of Botolan municipality downstream at risk: (1) a volume of 9.5 × 10⁷ m³ of lake water remains perched 0.8 km above sea level; (2) seismicity in 1991 demonstrated that the Maraunot Fault is still active and movements of sufficient magnitude could enlarge the outlet and the discharge through it; (3) more likely, however, with or without earthquake activity, landslides from the steep to overhanging channel walls could block the channel again, and a major rainstorm could then cause a rise in lake level and sudden breakouts; (4) intrusion of a new dome into the bottom of the lake, possibly accompanied by phreatic explosions, could expel large volumes of lahar-generating water.  相似文献   

吉林红石蓄能电站区域稳定性研究     

高常波  钟以章  万波  谷晓曦 《东北地震研究》2001,17(1):9-17

以有关规范为基础，分别从区域、近区域和场址区三个尺度对吉林红石蓄能电站场址的稳定性作了评价。从地质构造、新构造、火山、地震等方面来分析，区域和近区域均是稳定的，场址区内虽有5条断裂构造发育并有发生轻微崩塌和泥石流等灾害的可能，但不会对场址产生的影响，因而场址区也是稳定的。  相似文献