Land subsidence hazards in Hanoi, Vietnam

In China, there exist various regional sediments of the Quaternary such as loess soils of the Yellow River in northern China, lateritic soils in southern China and expansive soils in the broad plains of the Yangtze River. In the past, these Quaternary Sediments were often treated as special soils and their engineering properties tended to be studied accordingly. However, not much attention was given to relationships that may exist between these regional soils and, so far, the distribution and formation of regional Sediments have not been systematically studied. Only when it was found that regional classifications of soils (their names and their engineering properties) were in disagreement with each other for adjacent areas was the subject of relationship considered. Recently, the author has tested and studied a number of samples of various Quaternary regional Sediments. The relationship of their composition and microstructural features to their engineering properties has first been analysed on the basis of their basic properties. The distribution of regional sediments has then been studied in detail according to geographical environment and climatic conditions. Finally, formation and development processes for the various regional Sediments of the Quaternary in China have been postulated.

Provenance of fine-grained Quaternary sediments in the Tengger Sandy Desert recorded by Sr-Nd isotopes and its linkage with Quaternary aeolian silts on the Chinese Loess Plateau

In this paper, the earthquake-induced liquefaction susceptibility of Hanoi city is assessed using the recent published geological and geomorphologic data. A combination of classification methods based on the distribution of sedimentary deposits proposed by Youd and Perkins (1978) and geomorphologic units proposed by Iwasaki (1982) was applied. The subsurface lithology and geomorphologic maps were combined in a GIS platform for assessing the liquefaction susceptibility of Hanoi city.The resulting map shows that the liquefaction hazard of Hanoi city classified into four categories: high, moderate, low liquefaction potential and not likely areas. In the most of Hanoi area, the ground liquefaction potentials are moderate. The high liquefaction likely areas spread along the river beds and around the lake areas. The not likely and low liquefaction potential areas are observed mainly in the northwest and northeast of the study region such as Chanchim, Soc Son, and Bavi mountains. The present map can help the scientists, engineers, and planners to have the general information on regional liquefaction potential of the Hanoi city. ReferencesBird JF, Bommer JJ, 2004b. Earthquake Losses due to Ground Failure. Submitted to Engineering Geology, 75(2), 147-179.Bird Juliet F, Bommer Julian J., 2004a. Evaluating earthquake losses due to ground failure and identifying their relative contribution (Paper no. 3156). In Proceedings of the 13th world conference on earthquake engineering, Vancouver, B.C., Canada, august 1-6.Bui Van Duan, Nguyen Cong Thang, Nguyen Van Vuong, Pham Dinh Nguyen, 2013. The magnitude of the largest possible earthquake in the Muong La-Bac Yen fault zone. J. Sci. of the Earth, 35(1), 53-59.Dao Dinh Bac, Dang Van Bao, 2010. Geomorphologic characteristics, the ancient river beds system of the capital city and their values to the development of the Thang Long - Hanoi. International Workshop commemorating the 1000 years of Thang Long, Hanoi. Vietnam national University, Hanoi.Ganapathy, G. P., Rajawat, A. S., 2012. Evaluation of liquefaction potential hazard of Chennai city, India: using geological and geomorphological characteristics. Natural hazards, 64(2), 1717-1729.Goyal, A., Sinha, R., Chaudhari, M. and Jaiswal, K., 2001. Performance of Reinforced Concrete Buildings in Ahmedabad during Bhuj Earthquake January 26, 2001. Workshop on Recent Earthquakes of Chamoli and Bhuj: Volume I, Roorkee, India, May 24-26.Iwasaki, T., Tokida, K., Tatsuoka, F., Watanabe, S., Yasuda, S., Sato, H., 1982. Microzonation for soil liquefaction potential using simplified methods. In Proceedings of the 3rd international conference on microzonation, Seattle, 3, 1310-1330.Kuribayashi E., Tatsuoka, F., 1975. Brief review of liquefaction during earthquake in Japan," Soils and Foundations, 15(4), 81-92.Lew M, Naeim F, Huang SC, Lam HK, Carpenter LD, 2000. Geotechnical and geological effects of the 21 September 1999 Chi-Chi earthquake, Taiwan. Structural Design of Tall Buildings, 9, 89-106.National Research Council, 1985. Ishihara 1985. Liquefaction of Soils During Earthquake, National Academy press, 240, p.34. Nguyen Hong Phuong (Project Manager), 2002. Study of seismic risk of Hanoi city. Project code 01C-04/09-2001-2. Institute for Marine Geology and Geophysics, VAST.Nguyen Hong Phuong (Project Manager), 2007. Application of GIS technology to Development of a model for seismic risk analysis for Hanoi city. Institute for Marine Geology and Geophysics, VAST.Nguyen Hong Phuong (Project Manager), 2014. Estimation of Site Effects and Assessment of Urban Seismic Risk for Hanoi city. National Scientific Research Project Final report, Institute of Geophysics, VAST.Nguyen Hong Phuong and Pham The Truyen, 2014. Probabilistic seismic hazard assessment for South Central Vietnam. J. Sci. of the Earth, 36(4), 451-461.Phan Trong Trinh, Hoang Quang Vinh, Nguyen Van Huong, Ngo Van Liem, 2013. Active fault segmentation and seismic hazard in Hoa Binh reservoir, Vietnam. Cent. Eur. J. Geosci, 5(2), 223-235.Phan Trong Trinh, Ngo Van Liem, Nguyen Van Huong, Hoang Quang Vinh, Bui Van Thom, Bui Thi Thao, Mai Thanh Tan, Nguyen Hoang, 2012. Late Quaternary tectonics and seismotectonics along the Red River fault zone, North Vietnam. Earth-Science Reviews 114, 224-235.Susumu Yasuda, Nozomu Yoshida, Hiroyoshi Kiku, Hidenori Abo, and Masato Uda, 2001. Analyses of Liquefaction-Induced Deformation of Grounds and Structures by a Simple Method (March 26). International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics, p.27. http://scholarsmine.mst.edu/icrageesd/04icrageesd/session04/27.Updike, R. G., Egan, J. A., Moriwaki, Y., Idriss, I. M., Moses, T. L., 1988. A model for earthquake-induced translatory landslides in Quaternary sediments. Geological Society of America Bulletin, 100(5), 783-792.Vu Thanh Tam (Project Manager), 2014. Study and propose a reasonable threshold for preventing the subsidence caused by ground water exploitation, pilot application for downtown area of the Hanoi city. Final report of the Scientific research and technology development Project, National Center for water resource planning and investigation. Ministry of Natural Resources and Environment.Youd T. L., 1993. Liquefaction, ground failure and consequent damage during the 22 April 1991 Costa Rica earthquake. Abridged from EERI Proceedings: U.S. Costa Rica Workshop, http://nisee.berkeley.edu/costarica/Youd T. L., and Hoose S.N., 1977. Liquefaction Susceptibility and Geologic Setting, Proceedings, 6th World Conference on Earthquake Engineering, New Delhi, India, 6, 37-42.Youd T. L., and Perkins D. M., 1978. Mapping liquefaction-induced ground failure potential. Journal of the Geotechnical Engineering Division, ASCE, 104, GT4, 433-446.

The soil liquefaction potential has been evaluated for the Ariana Region because of its important socio-economic interest and its location. Liquefaction susceptibility mapping is carried out using a decisional flow chart for evaluation of earthquake-induced effects, based on available data such as paleoliquefaction, geological, groundwater depth, seismotectonic, sedimentary features and geotechnical parameters in particular laboratory testing like grain size analyses and state parameters. Survey results showed that some of these localities are considered as possible sites to soil liquefaction. Indeed, Quaternary alluvium deposits, paleo beaches and recent deposits that edge the lake and the sebka constitute the most susceptible locations to liquefaction. In the east and the west sides of the studied zone, Quaternary deposits are less susceptible to the liquefaction due to the groundwater level deepening and to the relatively old age of the deposits. Elsewhere sedimentary formations are classified as non-liquefiable as they are heavily compacted and old.

In the Republic of Lithuania, there had been almost no experience in the road (roadbed) construction prior to the Panemunė bypass in terms of very complex geological, geotechnical and paleogeomorphological territories. All the roads constructed in previous decades in the Nemunas River Delta were built practically without special geotechnical and geological research and the resulting problems were solved either on the spot during construction or rectified later upon the emergence of reclaimed deformation. The article analyzes the whole process of the geological and geotechnical research during the bypass construction – from the first exploration work and designing to construction completion. The geological and geotechnical research stages are described; methods, research conditions, mistakes made, and recommendations for geotechnical investigations under similar conditions in the future are given. At the same time, the article contains the detailed geological and geotechnical conditions of the bypass, roadbed construction problems, forecasts of the roadbed seating during the design and construction with the assumption of additional factors. The article provides and analyses the actual results of the bed deposition monitoring and further forecast of the bed deposition.

مطالعه مخاطرات طبیعی یکی از مهم‌ترین اصول اولیه برای توسعه شهرهای درحال‌توسعه و گسترش تأسیسات زیربنایی است. ارزیابی فعالیت‏های ژئودینامیکی با استفاده از داده‏های ریخت‏شناسی یکی از روش‏های مهم و کاربردی در این راستا تلقی می‏شوند. در این مقاله سعی شده با استفاده از داده‏های سنجش‌ازدور، مطالعات صحرایی نسبت به شناسایی چین‏های فعال در شهرستان یزد اقدام و برای اولین‏ بار چین‏های فعال منطقه شناسایی شوند. بررسی‏ها نشان می‏دهد در محدوده شرق تا شمال‏شرق این شهر باستانی تعداد حداقل 5 چین فعال وجود دارد که به‌عنوان مخاطرات جدی برای منطقه محسوب می‏شوند. مقایسه موقعیت این چین‏ها با فعالیت‏های لرزه، حاکی از انطباق برخی کانون‏های زمین‏لرزه‏ای در این منطقه است. بدیهی است عبور هرگونه تأسیسات و شریان‏های حیاتی ازجمله راه‏های مواصلاتی، خطوط گاز، آب و یا سایر زیرساخت‏های شهری در این منطقه نیازمند تمهیدات ویژه می‏باشد.

The proposed article is based on an analysis of publications on field observations published in the then Polish and Ukrainian periodicals, collections of materials from scientific forums at various levels, works collections of individual Polish and foreign scientific institutes, etc. The purpose of the article was an attempt to analyze and generalize the research results of the study area in the field of Quaternary geology and geomorphology. It should also be noted that publications from the listed sections of physical geography are encountered quite sporadically and in significantly smaller numbers than articles on purely geological disciplines such as mineralogy, petrography, lithology, tectonics, etc. The study of geological and geomorphological objects and processes was carried out on the territory of Western Volyn-Podillia, which at that time was a part of the Polish-Lithuanian Commonwealth. The works mainly concerned the study of the stratigraphy of anthropogenic sediments distributed in the Podillia loess and loess soils, continental glaciations and related glacial and fluvial-glacial deposits, surface and underground karst, etc. It was established that significant in volume and depth of generalization of works on the geological and geomorphological structure the region features at that time was not. The studies that were carried out were not systematic, they were often carried out on the researchers initiative and without adequate funding, with localization mainly in the territory with open at that time deposits of certain minerals types. Analysis of publications can be stated as follows: the study of Quaternary deposits of the region and loess in particular was carried out with extensive use of laboratory studies, paleontological method, chemical, particle size distribution mineralogical and petrographic analyzes, the method of separation of loess minerals in heavy liquids, paleontological and archaeological observations, etc., were progressive at that time. It should be noted that individual reports on the determination of the age of the Quaternary strata were poorly synchronized with each other and a reliable generally accepted scale for the division of these deposits in this period was not agreed. During this period, factually substantiated schemes of geomorphological zoning of both the Podillia region as a whole and its individual components were proposed. Regular relationships of the relief features of the region with the lithogenic base, neotectonic movements, glacial and fluvial-glacial processes are traced. Significant progress is noted in the study of stratigraphy, lithology of local loess strata, problematic issues of their genesis are discussed. Among the few works on the study of the loess cover of Volyn-Podillia, the work of Yu. Polianskyi and Yu. Tokarskyi attracts attention first of all. The works on the study of loess are important due to: a) their almost ubiquitous distribution in the described territories; b) value for stratigraphic subdivision of the Pleistocene; c) controversial genesis; d) widespread use for the production of bricks and tiles. Work on the study of surface and underground forms of the Podillia karst has spread. Systematic mapping of individual underground cavities begins which gave impetus to their use in the future as objects of tourism. The largest number of works is devoted to the problems of studying the relief and modern physical and geographical processes in the interwar period. At the same time, along with purely descriptive publications, works appear where conclusions are based on the use of cartographic materials, which allowed researchers to identify significant patterns in the morphological features of the region. In the period under study, numerous publications by soil scientists also appeared, in which Quaternary sediments are considered as parent rocks on which soils were formed, the dependence of the type of soil on the lithology of the underlying rocks is established.
 In general, the works of Polish and Ukrainian researchers in the characterized period laid a reliable foundation for modern ideas about the geological and geomorphological features of the region.
 Keywords: geomorphological studies, Quaternary deposits, glacial deposits, stratigraphy, morphology, loess deposits.

This work is dedicated to Antanas Karolis Giedraitis (Antoni Karol Giedroyć, A.K. Gedroïz, А.K. Гедройц) (1848–1909) geological research that he did in Lithuania territory for geological mapping. In the History of Science, A.K. Giedraitis is called the first professional geologist of Lithuania, who investigated geology of our and neighboring countries. In 1895 he compiled a geological map of very large territory – Russian Empire governorates of Vilnius, Kaunas, Suvalkai, Gardinas, and Minskas according to international standards. It is important to understand A.K. Giedraitis’ approach to the formation of Quaternary sediments and the theory of polyglacialism. He took at that time the bold position that this entire region two or even three times had been covered by a glacier that advanced from the North. Based on the weathering (wearing) of erratic boulders and glacial incisions, he tried to describe the limits of glacier expansion and the directions of its movement. A.K. Giedraitis’ professional achievements are well-known, they are evidenced by the detailed reports and publications of his geological research in German, Polish, and Russian, which were published in 1886, 1887, and 1894. A summary of all his research was published in 1895, together with a geological map to a scale of 1:420 000. Interestingly, research carried out nowadays has confirmed some of the more than 130-year-old insights of A.K. Giedraitis about the geological formation of our country.

The Department of Geomorphology and Palaeogeography of the Faculty of Geography at the Ivan Franko National University of Lviv employs a group of palaeogeographers (A. Bogucki, O. Tomeniuk, A. Yatsyshyn, R. Dmytruk), which comprehensively studies Quaternary sediments in Western Ukraine and other territories of the country. The thematic focus of palaeogeographic research is very diversified: the study of key sections of Quaternary sediments; conditions of formation and structure of periglacial loess-palaeosol sequences; research of the deposits of the glacial complex; periglacial processes and forms; the role of tectonics in the formation of Quaternary sediments; interdisciplinary research of the Palaeolithic; engineering and geological investigations; geophysical research; mineralogical research; weathering of anhydrite; study of the Holocene stage of the formation of the Dnister River valley; river terraces; lithology of alluvium; study of the Vyshnia River valley; malacological research; research of travertines, history of geography, etc. The selected issues are a priority research topic of the palaeogeographic group of the Department of Geomorphology and Palaeogeography. On the occasion of the 70th anniversary of the department, an attempt to summarize the scientific achievements of palaeogeographers over the past twenty years, particularly in thematic directions of research, was made. A large amount of new original factual material has been received, a significant number of international and Ukrainian scientific grants have been implemented, ten PhD students have defended their theses and received a PhD degree, more than 500 scientific papers have been published, more than half of which are in European Union languages. Due to the limited scope of this article, the greatest attention among all of the publications is paid to selected monographic works, collections of scientific papers prepared by researchers, papers in the journals from Scopus and Web of Science databases, and some others. It is worth mentioning the close cooperation of palaeogeographers of the Faculty of Geography with researchers from Ukraine, Poland, Belarus, Lithuania, France, Belgium and other countries. Without doubts, there are all the reasons to talk about a progressive palaeogeographic school at the Faculty of Geography, whose work is gaining momentum. Key words: palaeogeography; key sections; loess-palaeosol sequence; Quaternary period; periglacial processes; Palaeolithic.

The study uses the applications of remote sensing in analyzing the main topographic features of the study area. The digital elevation model derived from the Shuttle Radar Topography Mission (SRTM) satellite is used to devise spillway torrents and their tributaries of the different drainage basins in the study area. The digital rainfall data recorded by the Tropical Rainfall Measuring Mission (TRMM) climate research satellite is used to determine places with the highest rainfall within the different drainage basins in the area. Other satellite data (e.g. Landsat-8) are used in identifying and studying the various geological structures in the study area, which intersect the spillway torrents. Such areas may allow seizure of large quantities of water as potential, close to the surface, groundwater (Quaternary) aquifer. Areas of potential hydrological traps have been identified and marked for further geophysical (geoelectrical) surveys. The geophysical studies helped in identifying the shallow geological structures and the thickness of the subsurface sediments. It also assists in determining the size of the groundwater aquifer and the water quality within these aquifers. The study showed a decline of freshwater aquifer in Quaternary sediments. The Tertiary groundwater aquifer is the most prevalent, where this appears normal saline aquifer. All the aquifers within the study area are being recharged from Quaternary sediments by rainwater. The cumulative annual precipitation rate increases in the South-East of the study area, specifically over Wadi Khulais and significantly drops to lower rainfall rates in the rest of the region. Running water permeates the Quaternary sediments, which in turn infiltrates and recharges the Tertiary aquifer. The salinity of the latter depends mostly on the nature of its constituent rocky material.

Introduction. Sloping structures (quarry sides, dumps, banks, cuts, dams, etc) stability forecasting accuracy improvement requires detailed elaboration of physical-mechanical properties of the rock mass under consideration. Traditional methods of well engineering-geological exploration and hydrogeological monitoring are therefore supplemented by geophysical study. Research aim is to diagnose unstable deconsolidated and wetted zones in marginal masses for the purpose of further forecast of quarry sides stability. Methodology. Databases of geophysical studies obtained by the expeditions of the services of the Republic of Uzbekistan at Angren open pit. Results. For the test area represented by 11 seismic stations at the southern side of the quarry, the criterion assessing the state of the site as potentially landslide hazardous according to the results of circular seismic sounding has been experimentally obtained. With the use of this criterion, in the plan of the landslide zone the borders have been established. For the test area represented by 16 geophysical profiles at the northers side, by electrical profiling graphs and geological sections for the corresponding profiles, 58 "Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal". No. 1. 2020 ISSN 0536-1028 the following regularities have been found: at profile areas adjacent to the runs (rivers), local negative anomalies of effective resistivity up to 20–50 Ohm ∙ m are observed connected with soils wetting; between the anomalous areas the alternation of effective resistivity qualitatively coincides with the alternation of the thickness of a layer of loose deposits. By the arrangement of the negative anomalies borders at the graphs pf effective resistivity dependence on the spread of the profile along all profiles (PR1–PR16), the borders of the wetted zones were established in the plan of the test area. Summary. For geomechanical processes monitoring in the landslide zones it is advisable to apply the method of circular seismic sounding determining the value and the anisotropy coefficient according to the extreme values of compressional arrival time. For the conditions of the Angren open pit, the criterion of potential hazard of landslide development is the value of the anisotropy coefficient higher than 1.6. When elaborating the detailes of the physical properties of landslide zones in quarry sides which are weakened by sand-clay Quaternary sediments, by the method of electrical profiling it is advisable to use: the linear dependence on the thickness of Quaternary sediments on the value of the effective resistivity; hyperbolic dependence of soils relative wetness within the water saturation zones on the value of the effective resistivity ascribed to the reference value defined in the site of soil samples collection, and the borders of wetting zones are to be established by the negative anomalies at electrical profiling graphs. In order to construct the solid geologicalgeophysical models of the landslide zones of the sides, in addition to the geological sections data, the following results of geophysical sounding should be used: the boundaries of landslide zones in the plan, detailed contact geometry of loose Quaternary sediments with bedrock; soil properties modified by wetting

The Quaternary deposits in the studied area comprise sand of fluvial origines, separated by clay deposits of swamp, backswamp, and floodplain. The fluvial channel was characterized by the increase and decrease of axial bodies. Vertically, the character of fine-grained deposits showed the changing in colour and percentage of humic and peat contents. Differences in the amount of clastic supply was caused by the changes in climatological conditions. Climate is an important and independent force in controlling the weathering, erosion, and sediment supply to Quaternary deposits of swampy alluvial basin. A systematic change in the type of fluvial system on the swampy alluvial plain could be the result of the changes in the sediment supply and ratio between coarse-grained bedload and suspended load. It means, the sedimentary processes on the basin can develop under the condition of climatic changes. Key words: Quaternary deposit, fluvial, swamp, climate

After many years of geological and geophysical studies, the South Yellow Sea (SYS) is believed to be the front of South China Block when colliding with the North China Block. The SYS basin is filled by the Mesozoic-Cenozoic terrigenous sediments overlying the Pre-Paleozoic and Mesozoic-Paleozoic marine sediments. As the results of the multi-stage tectonic activity and sedimentation events, the SYS basin has very complex structure. Many geophysical surveys have been conducted to uncover the detailed basin structures. However, the connection of the shallow and deep structures remain to be studied, either due to the low resolution of crustal structure for the magnetic and gravity methods or due to the lack of deep structure information in the shortoffset marine seismic data. Here, we use the first-arrival time data of a wide-angle OBS array (OBS2013) and the multiscale seismic tomography (MST) to invert the P-wave velocity structure of the SYS. The MST method is devised to cope with the poor determinacy caused by the uneven raypaths coverage. By decomposing the inverted area with the sub-models with different cell sizes, the MST method can invert the velocity model on the meshes with correct scale and provide a smoother velocity model that is suitable for the geologic interpretation. The accuracy of the first-arrival times is improved after adopting a five-station moving average method, which suppresses the random noise and enhances the first-arrival waveforms by averaging the nearby traces. The selection of data is based on the angle between the array and the shot-receiver line. Here, the picks with angle less than two degrees are adopted to avoid the off-line influence. To show the resolution of our MST algorithm, we conducted a checker-board test using the same inversion parameters and shotreceiver geometry with the case of field-data inversion. The resulted velocity profile shows that the velocity anomalies shallower than 6 km depth is properly recovered. By comparing the inverted velocity model with multi-channel seismic profile, the sedimentary formation is interpreted, referring to gravity and magnetic data. The final inverted velocity model shows strong lateral and vertical velocity variations. In the vertical, the sedimentary formation is divided into two parts by the Indosinian surface. The top one is the extensional formation with low P-wave velocity, and the other is the extrusion formation carrying a high speed feature. In the transverse, six boundaries of lateral velocity (F1-F6) were interpreted as six faults, which control the development of the SYS basin. Based on the research results, we infer F1 to be the boundary of Jiaolai basin and F4 to be a strike-slip fault, which is a normal fault on its top and the reverse fault at its bottom. The faults divide the sedimentary formation beneath the survey line into low or high P-wave velocity zones. Four low velocity zones (LVZs, 5 km . s (1)) are identified beneath 2013OBS line with the prior gravity, magnetic and conventional seismic data. The LVZs, namely I, II, III and IV, have the similar gravity and magnetic anomaly characteristics, and are demonstrated to be formed in the faulted period. In the HVZs, area V consists of the metamorphic rocks formed during the collision orogeny in the Qianliyan Uplift. The other four HVZs show as high-value gravity anomaly and low-value magnetic anomaly in the Northern Depression, which correlate with the feature of the marine sedimentary strata. However, sandstone is confirmed located at the strata with 2 km thickness in VIII and IX (buried depth <6 km) with a lower velocity (5 km . s P-wave), referring to the V-P/V-S. Based on the short wavelength magnetic anomaly, there might be igneous rocks in the HVZ IX of the Central Uplift.

The Vinodol Valley, situated in the north-western Adriatic in Croatia, is characterized by complex geological and morphological conditions. Palaeogene flysch deposits form the inner parts of the valley, while the steep valley flanks are composed of Cretaceous and Palaeogene carbonate rocks. Flysch bedrock is mostly covered by diverse Quaternary deposits, among which deposits originating from carbonate rock slopes are abundant. During previous investigations, based on conventional field geological mapping and mostly conducted in the north-western and central parts of the Vinodol Valley, such Quaternary deposits were addressed to the tectonic evolution of the study area and rockfalls, respectively. Therefore, they were generally named as Quaternary rockfall breccias, or Quaternary rockfall deposits. This study presents six types of the Quaternary deposits originating from carbonate rock slopes and their spatial distribution in the whole Vinodol Valley (64.57 km2 ), which are identified and mapped based on the visual interpretation of 1-m airborne LiDAR (Light Detection and Ranging) Digital Terrain Model (DTM). Lithological materials are classified according to engineering geological principles, and represent engineering formations. New insight into the types, shapes, geometric characteristics and hypsometrical positions of the identified sedimentary bodies indicate that some other gravitational mass movements, and not just rockfalls, played an important role in the formation of the Quaternary deposits originating from the carbonate rock slopes in the Vinodol Valley. This study also presents the potential of the visual interpretation of high-resolution LiDAR DTM for identification and mapping of superficial deposits in study areas characterized by complex geological and morphological conditions.

The Kachchh Mainland Fault (KMF) is a major E–W trending seismically active fault of the Kachchh palaeorift basin whose neotectonic evolution is not known. The present study deals with the eastern part of the KMF zone where the fault is morphologically expressed as steep north facing scarps and is divisible into five morphotectonic segments. The Quaternary sediments occurring in a narrow zone between the E–W trending KMF scarps and the flat Banni plain to the north are documented. The sediments show considerable heterogeneity vertically as well as laterally along the KMF zone. (The Quaternary sediments for a northward sloping and are exposed along the north flowing streams which also show rapid decrease in the depth of incision in the same direction.) The deposits, in general, comprise coarse as well as finer gravelly deposits, sands and aeolian and fluvial miliolites. The Quaternary sediments of the KMF zone show three major aggradation phases. The oldest phase includes the colluvio-fluvial sediments occurring below the miliolites. These deposits are strikingly coarse grained and show poor sorting and large angular clasts of Mesozoic rocks. The sedimentary characteristics indicate deposition, dominantly by debris flows and sediment gravity flows, as small coalescing alluvial fans in front of the scarps. These deposits suggest pre-miliolite neotectonic activity along the KMF. The second aggradation phase comprises aeolian miliolites and fluvially reworked miliolites that have been previously dated from middle to late Pleistocene. The youngest phase is the post-miliolite phase that includes all deposits younger than miliolite. These are represented by comparatively finer sandy gravels, gravelly sands and sand. The sediment characteristics suggest deposition in shallow braided stream channels under reduced level of neotectonic activity along the KMF during post-miliolite time evidenced by vertical dips of miliolites and tilting of gravels near the scarps. The tectonically controlled incision and dissection of the Quaternary deposits is the result of neotectonic activity that continues at present day. The overall nature, sedimentary characteristics and geomorphic setting of the sediments suggest that the KMF remained neotectonically active throughout the Quaternary period.