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Aftershocks of the 2 April 2024 Mw 7.4 Hualin, Taiwan Earthqauke 2024 年 4 月 2 日台湾花莲 7.4 级地震的余震 Earthqauke

IF 1.3 4区地球科学 Q3 Earth and Planetary Sciences

Journal of the Geological Society of India

Pub Date : 2024-06-01 DOI: 10.17491/jgsi/2024/173907

Rekapalli Rajesh, Harsh K. Gupta

A devastating Mw 7.4 earthquake occurred in Taiwan on the 2 April 2024 at 23:58:11 UTC claiming 14 human lives, injuring over 1000 and causing wide spread structural damage. Moderate aftershocks of major earthquakes tend to cause further damage to already weakened built structures. An assessment of the duration of occurrence of such aftershocks is helpful in post earthquake recovery phase. This earthquake is the most significant earthquake to have occurred after 25 years of the 21 September 1999 Mw 7.7 Chi-Chi earthquake in Taiwan. Our study indicates that there was a paucity of Mw ≥ 5 aftershocks for the Chi-Chi earthquake as only 45 such aftershocks occurred in 40 days. However, an increase in the number of Mw 4.5 earthquakes was observed compared to the background seismicity. Using Omori’s Law, we estimated the duration of Mw ≥ 4.5 aftershocks using the data of first 14 days to be 110 days, that matches quite well with the the Chi-Chi earthquake sequence. The 2 April 2024 Hualin earthquake is quite similar to the 1999 Ch-Chi earthquake. There is a paucity of Mw ≥ 5 for the Hualin earthquake. No such after shock has been recorded after 7 April 2024. However, Mw ≥ 4.5 aftershoks are continuing to occur. Our study, using the data of 14 days after the Hualin earthquake, indicates that Mw ≥ 4.5 aftershocks for the Hualin earthquake shall continue for ∼ 80 days.

2024 年 4 月 2 日（世界协调时）23:58:11，台湾发生了一次破坏性的 7.4 级地震，造成 14 人死亡，1000 多人受伤，并造成大范围的结构性破坏。大地震的中度余震往往会对已经脆弱的建筑结构造成进一步破坏。评估此类余震发生的持续时间有助于震后恢复阶段。这次地震是台湾 1999 年 9 月 21 日发生 7.7 级地震 25 年后发生的最重大地震。我们的研究表明，在 Chi-Chi 地震中，Mw ≥ 5 的余震很少，在 40 天内只发生了 45 次这样的余震。然而，与背景地震相比，观察到 Mw 4.5 级地震的数量有所增加。根据大森定律，我们利用前 14 天的数据估算出 Mw ≥ 4.5 余震的持续时间为 110 天，这与池芝澳地震序列相当吻合。2024 年 4 月 2 日的华林地震与 1999 年的赤池地震十分相似。华林地震的震级≥5 级的地震极少。2024 年 4 月 7 日之后没有记录到此类余震。然而，Mw ≥ 4.5余震仍在继续发生。我们利用华林地震后 14 天的数据进行的研究表明，华林地震 Mw ≥ 4.5 余震将持续 80 天。

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引用次数: 0

Spatial Vulnerability Investigation by Morphotectonic Analysis of the Mandakini River Basin near Kedarnath, Uttarakhand, India using SRTM DEM in a GIS Platform and GPS Data 利用 GIS 平台中的 SRTM DEM 和 GPS 数据，通过形态构造分析对印度北阿坎德邦 Kedarnath 附近的 Mandakini 河流域进行空间脆弱性调查

IF 1.3 4区地球科学 Q3 Earth and Planetary Sciences

Journal of the Geological Society of India

Pub Date : 2024-06-01 DOI: 10.17491/jgsi/2024/173913

Siba Sundar Sahu, Niladri Bhattacharjee

Tectonomorphic study was carried out to evaluate the intensity of tectonic activity in and around the Mandakini River basin (1330 sq. km area) near Kedarnath. The area has witnessed several vulnerable landslides and devastating floods in the recent past. Quantitative parameters such as Bifurcation Ratio (BR), Asymmetry Factor (AF), Valley floor width Index (Vf), Hypsometric Integral (HI), Stream-length gradient Index (SL index), Sinuosity Index (Sp) and two qualitative parameters such as drainage orientation survey and the hypsometric curve is used to evaluate the spatial tectonomorphic susceptibility of the different watersheds of the Mandakini River basin. High BR, medium to high AF and low Vf show a very high vulnerability mostly close to MCT. High Sp and medium HI values are linked with continuous tectonic disturbances followed by erosion. High SL index demarcates high tectonic instability along different portions of streams which is prone to tectonic perturbation. The Index of Relative Active Tectonic also suggests variability in tectonic activities varies from very high tectonic activity to high tectonic activity. Regional geology and lower-order stream orientation survey of the study area revealed that the initial NE-SW shortening direction of the Himalayan orogeny is rotated to the N-S direction in the later stage. The resulting deformation style is expressed by the NW–SE and NE–SW striking lineaments and WNW–ESE striking thrust dipping moderately toward the north. Processed GPS data shows the rotation of the maximum principal compression direction and resultant readjustment of strains are linked with the revolving of the Indian Plate in the anticlockwise direction which is responsible for the orientation of different discontinuities, developing maximum shear stress conditions, weak internal friction and negligible resistance by low-strength rock. The present tectonic setup of the Kedarnath region is highly susceptible to devastating floods and vulnerable landslides.

为了评估曼达基尼河流域（面积为 1330 平方公里）及其周围地区的构造活动强度，我们在克达尔纳特附近开展了构造形态研究。最近，该地区发生了数次脆弱的山体滑坡和毁灭性的洪水。我们采用了分叉率（BR）、不对称系数（AF）、谷底宽度指数（Vf）、湿度指数（HI）、溪流长度梯度指数（SL 指数）、正弦指数（Sp）等定量参数以及排水方向调查和湿度曲线等两个定性参数来评估曼达基尼河流域不同流域的空间构造形态易感性。高 BR 值、中到高 AF 值和低 Vf 值表明，大部分靠近 MCT 的流域非常脆弱。高 Sp 值和中等 HI 值与持续的构造扰动和侵蚀有关。高 SL 指数表明溪流不同部分的构造高度不稳定，容易受到构造扰动。相对活跃构造指数还表明，构造活动的变化从非常活跃到非常活跃不等。研究区域的区域地质和低阶溪流走向调查显示，喜马拉雅造山运动最初的东北-西南缩短方向在后期旋转为东北-西南方向。由此产生的变形方式表现为 NW-SE 和 NE-SW 走向线状构造，以及 WNW-ESE 走向推力构造，并适度向北倾斜。经过处理的全球定位系统数据显示，最大主压缩方向的旋转和由此产生的应变重新调整与印度板块沿逆时针方向的旋转有关，这导致了不同不连续面的走向、最大剪应力条件的形成、内部摩擦力的减弱以及低强度岩石阻力的减弱。凯达尔纳特地区目前的构造设置极易造成毁灭性的洪水和脆弱的山体滑坡。

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引用次数: 0

Defining the Active Faults and the associated Geotechnical Properties using MASW Technique in Dehradun district and its Adjoining Regions, India 利用 MASW 技术确定印度德拉敦地区及其毗邻地区的活动断层和相关岩土特性

IF 1.3 4区地球科学 Q3 Earth and Planetary Sciences

Journal of the Geological Society of India

Pub Date : 2024-06-01 DOI: 10.17491/jgsi/2024/173908

P. Sivasankar, K. Satish Kumar, Guru Dayal Singh, K. Swapna Sri, Prabha Pandey, Anand K. Pandey, D. Srinagesh

Dehradun lies in the intermontane Dun Valley in the Garhwal Sub Himalaya, which lies with the Main Boundary Thrust (MBT)- Himalayan Frontal Thrust (HFT) tectonic wedge with other intrawedge faults. These faults may rupture during a great earthquake and cause damage to the existing civil structures in the fault zone. Therefore, it is essential to characterise the active faults in and around Dehradun. We carried out 2D Shear wave velocity profiles across the Markanda Thrust, Rajban Fault, Bata Fault, Santaurgarh Thrust, Bhauwala Thrust, and Majhaun Fault at 18 sites using the Multichannel Analysis of Surface Wave (MASW) technique. The obtained shear wave velocity is further utilised to calculate geotechnical parameters like the average shear wave velocity (Vs30), soil stiffness, amplification factor, and predominant frequency. The weak, weathered or shear zones and dislocations are mapped in terms of a low shear wave velocity layer overlain by a high shear wave velocity layer at deeper depths near identified fault or thrust locations. The active fault/thrust zones in the Dun Valley have a shear wave velocity of 130 m/s to <1500m/s and consist of stiff soil to dense soils of class D to C as per the National Earthquake Hazard Reduction Programme (NEHRP) classification. This study contributes to a better understanding of the seismic characteristics of Dehradun and its surroundings, which is useful for earthquake mitigation studies.

德拉敦位于喜马拉雅山下加尔瓦尔地区的敦谷山间，与主边界推力（MBT）- 喜马拉雅正面推力（HFT）构造楔和其他边缘断层相连。这些断层可能会在大地震中断裂，并对断层区内现有的民用建筑造成破坏。因此，对德拉敦及其周边地区的活动断层进行特征描述至关重要。我们采用多通道表面波分析 (MASW) 技术，在 18 个地点对马尔坎达断层、拉杰班断层、巴塔断层、圣塔尔加断层、包瓦拉断层和马杰翁断层进行了二维剪切波速度剖面测量。获得的剪切波速度可进一步用于计算岩土参数，如平均剪切波速度 (Vs30)、土壤刚度、放大系数和主要频率。弱区、风化区或剪切区和错动区在已确定的断层或推力位置附近的较深层被低剪切波速层和高剪切波速层所覆盖。邓谷的活动断层/推力带的剪切波速为 130 米/秒至小于 1500 米/秒，根据国家地震危险性减灾计划（NEHRP）的分类，由 D 级至 C 级的坚硬土壤至致密土壤组成。这项研究有助于更好地了解德拉敦及其周边地区的地震特征，对地震减灾研究很有帮助。

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引用次数: 0

Delineation of Shale Gas Play from Non-Pay Zones Using Elastic and Mechanical Properties of Organic-Rich Shales, Southern Punjab Platform, Pakistan 利用巴基斯坦南旁遮普平台富含有机质页岩的弹性和机械特性，从非付费区划分页岩气层

IF 1.3 4区地球科学 Q3 Earth and Planetary Sciences

Journal of the Geological Society of India

Pub Date : 2024-06-01 DOI: 10.17491/jgsi/2024/173916

P. Khalid, Irfan Raza, Muhammad irfan Ehsan

Energy demand has increased due to socio-economic development, and depletion in conventional hydrocarbon reservoirs. Due to this, unconventional hydrocarbon reservoirs have received considerable attention. Among the variety of unconventional hydrocarbon reservoirs, shale gas is the most significant unconventional alternate energy resource. The Cretaceous organic-rich shales of Sembar Formation are considered a shale gas play however the composition and mineralogy of these shales are extremely heterogeneous in the central parts of the Indus basin, especially in the southern extent of the Punjab Platform. The primary objective of the research is to employ petrophysical analysis to characterize shales to assess their potential for shale gas exploration. To estimate various petrophysical parameters, this study utilizes wire-well logs acquired from the J-01 well. The findings reveal that total organic content (TOC) and kerogen volume are present in significant volume, indicating the shale’s viability as a shale gas play. To evaluate shale brittleness (B) and to differentiate between ductile and brittle behavior, elastic parameters including acoustic impedance, elastic moduli, and Poisson’s ratio (PR) are computed. The cross plot of Young’s modulus and PR indicates elevated brittleness values, pointing to brittle behavior of these shales favorable conditions for fracking and horizontal drilling. Moreover, a set of three logs – neutron porosity log, bulk density log, and gamma-ray log – were used for facies modeling and identification of different lithologies. The facies modeling effectively discriminate shale intervals from other lithologies, demonstrating higher porosity and density. As a result, the organic-rich shale intervals within the Sembar Formation exhibit promising potential as a shale gas play in the southern Punjab Platform.

由于社会经济的发展和常规碳氢化合物储层的枯竭，能源需求不断增加。因此，非常规碳氢化合物储层受到了广泛关注。在各种非常规油气藏中，页岩气是最重要的非常规替代能源资源。白垩纪富含有机质的森巴地层页岩被认为是页岩气的一种，但在印度河盆地中部，尤其是旁遮普地台南部，这些页岩的成分和矿物学极为不均匀。研究的主要目的是利用岩石物理分析来描述页岩的特征，以评估其页岩气勘探潜力。为了估算各种岩石物理参数，本研究使用了从 J-01 井获得的线井测井记录。研究结果表明，页岩中含有大量的总有机物含量（TOC）和角质，这表明该页岩具有开采页岩气的潜力。为了评估页岩脆性（B）并区分韧性和脆性行为，计算了包括声阻抗、弹性模量和泊松比（PR）在内的弹性参数。杨氏模量和泊松比的交叉图显示脆性值升高，表明这些页岩的脆性行为有利于压裂和水平钻探。此外，中子孔隙度测井、体积密度测井和伽马射线测井这三种测井记录被用于建立岩相模型和识别不同岩性。岩相建模可有效区分页岩与其他岩性，显示出较高的孔隙度和密度。因此，Sembar 地层中富含有机质的页岩层段有望成为旁遮普地台南部的页岩气层。

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引用次数: 0

Landslide Occurrences under Diverse Landuse/cover in Lower Kosi Watershed, Central Himalaya 喜马拉雅中部下科西流域不同土地利用/覆盖下的滑坡发生率

IF 1.3 4区地球科学 Q3 Earth and Planetary Sciences

Journal of the Geological Society of India

Pub Date : 2023-12-20 DOI: 10.1007/s12594-023-2525-4

Vinita Joshi, Anita Pande

Present study was related to land degradation after landslide and risk analysis of Lower Kosi watershed in Central Himalaya using RS and GIS. The study was aimed to identifying the relation of land use with landslide activity in Himalayan terrain and landslide management. The landslide inventory map was prepared for the detailed study with the help of Google Earth Image and field verifications. Landslide had been sub-categorized into two categories; natural and road induced. The land use map was prepared from Google Earth image followed by toposheets. Statistical analysis of landslide frequency and density as well as frequency and density ratios were applied. The collected data was evaluated in combination with GIS. The relationship between land use categories and landslide occurrences was determined. The landslide frequency ratio (FR) and density ratio (DR) were analyzed. The FR and DR value of 1 is an average value. Hence, the value of ratio more than 1 signifies a strong relationship between landslides and the given factor while ratio values less than 1 registers a poor relationship. The FR and DR values were >1.0 in the areas of fallow land, barren/rocky land, agricultural land and open forest revealing a strong relation to landslide processes while the lesser values of FR and DR in ‘dense forest’ area determines the impact of sufficient vegetation cover on the least occurrence of landslides. This study may be applicable for new and existing land use planning projects as the adopted methodology provides rapid estimation of landslide vulnerability of the area.

本研究利用 RS 和 GIS 对喜马拉雅中部下科西流域滑坡后的土地退化和风险进行了分析。研究旨在确定喜马拉雅地形中土地利用与滑坡活动的关系以及滑坡管理。在谷歌地球图像和实地核查的帮助下，为详细研究绘制了滑坡目录图。滑坡分为两类：自然滑坡和道路滑坡。土地利用图是根据谷歌地球图像和地形图绘制的。对滑坡频率和密度以及频率和密度比进行了统计分析。结合地理信息系统对收集到的数据进行了评估。确定了土地利用类别与滑坡发生率之间的关系。分析了滑坡频率比（FR）和密度比（DR）。频率比和密度比的 1 值为平均值。因此，比率值大于 1 表示滑坡与给定因素之间的关系密切，而比率值小于 1 则表示关系不密切。在休耕地、贫瘠/石质地、农田和疏林区，FR 值和 DR 值均为 1.0，表明滑坡过程与这些因素关系密切，而在 "密林 "区，FR 值和 DR 值较小，这说明充足的植被覆盖对减少滑坡的发生具有重要影响。这项研究适用于新的和现有的土地利用规划项目，因为所采用的方法可快速估算该地区的滑坡脆弱性。

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引用次数: 0

Recent Trends and Techniques in the Study of Brittle Deformation: Implications in Upper Crustal Fluid Flow 脆性变形研究的最新趋势和技术：上地壳流体流动的影响

IF 1.3 4区地球科学 Q3 Earth and Planetary Sciences

Journal of the Geological Society of India

Pub Date : 2023-12-20 DOI: 10.1007/s12594-023-2535-2

Tridib Kumar Mondal

引用次数: 0

Super High Organic Sulphur (SHOS) in Tertiary coals of North-East India 印度东北部第三纪煤炭中的超高有机硫（SHOS）

IF 1.3 4区地球科学 Q3 Earth and Planetary Sciences

Journal of the Geological Society of India

Pub Date : 2023-12-20 DOI: 10.1007/s12594-023-2538-z

Manabendra Nath

引用次数: 0

Indian Endeavour in Antarctic Geoscience 印度在南极地球科学方面的努力

IF 1.3 4区地球科学 Q3 Earth and Planetary Sciences

Journal of the Geological Society of India

Pub Date : 2023-12-20 DOI: 10.1007/s12594-023-2534-3

Rasik Ravindra

引用次数: 0

Insights from the Five-day National Training Programme on “Earth Observation Data Analytics for Disaster Management Focusing on Flood and Drought” 为期五天的 "地球观测数据分析促进以水灾和旱灾为重点的灾害管理 "国家培训计划的启示

IF 1.3 4区地球科学 Q3 Earth and Planetary Sciences

Journal of the Geological Society of India

Pub Date : 2023-12-20 DOI: 10.1007/s12594-023-2539-y

Surajit Ghosh, Jayesh Mukherjee, Anuva Chowdhury, Kounik De Sarkar, A. Taron, Biplab Biswas, Ashish Ghosh

引用次数: 0

Numerical Analysis of a Tunnel Passing through Jointed Rockmass 隧道穿越节理岩体的数值分析

IF 1.3 4区地球科学 Q3 Earth and Planetary Sciences

Journal of the Geological Society of India

Pub Date : 2023-12-20 DOI: 10.1007/s12594-023-2524-5

Harshal Verma, Arunava Ray, Rajesh Rai, Bappaditya Manna, T. N. Singh

With the increase in the pace of development, the demand for tunnels has increased in recent years. Analysing the stability of a tunnel in a fractured rock mass is a very challenging and cumbersome activity. The tunnel stability depends on the strength of the rock, joints bolt strength, in-situ stresses, and their orientation. This paper focuses on constructing tunnels in fractured/jointed rock mass. Three different software namely Rocscience Phase2 (finite element based), FLAC^3D (finite volume based) and PFC^3D (distinct element based), were used to analyse the performance and stability under static and dynamic loading conditions. The geomaterial properties used for the analysis were taken from data obtained after laboratory testing and based on available literature. The effect of joint orientation and bolt length was analysed using Phase 2 assuming plain strain conditions. The effect of earthquake and performance of fully grouted, energy absorbing and deformation-controlled bolts under seismic loading conditions were compared using FLAC^3D. While the 3D distinct element analysis of geometry was performed using PFC^3D to evaluate the effect of joints and their orientation. The performance of the different types of bolts was also analysed numerically. The behaviour of bolts can be customised using the ‘fish‘function. The results indicate that analysis must incorporate the fusion of various numerical simulation techniques like finite element-, finite volume- and distinct element-based methods for more reliable results.

随着发展速度的加快，近年来对隧道的需求也在增加。分析断裂岩体中隧道的稳定性是一项极具挑战性的繁琐工作。隧道稳定性取决于岩石强度、连接螺栓强度、原位应力及其方向。本文的重点是在断裂/节理岩体中建造隧道。本文使用了三种不同的软件，即 Rocscience Phase2（基于有限元）、FLAC3D（基于有限体积）和 PFC3D（基于独特元素），来分析静态和动态加载条件下的性能和稳定性。用于分析的土工材料属性来自实验室测试后获得的数据，并以现有文献为基础。使用第 2 阶段分析了连接方向和螺栓长度的影响，并假设了平应变条件。使用 FLAC3D 比较了地震的影响以及地震荷载条件下全灌浆螺栓、能量吸收螺栓和变形控制螺栓的性能。同时，使用 PFC3D 对几何形状进行了三维独特元素分析，以评估接头及其方向的影响。此外，还对不同类型螺栓的性能进行了数值分析。使用 "fish "功能可以定制螺栓的性能。结果表明，分析必须结合各种数值模拟技术，如有限元、有限体积和基于不同元素的方法，才能获得更可靠的结果。

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