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We analyze temporal variations in the travel times of both P and S waves (Vp and Vs) for 14 months at Toyohashi (central Japan) with a continuously operating vibration source that could efficiently produce both P and S waves. Seismic waves produced by the source, which is called the accurately controlled routinely operated signal system (ACROSS), are recorded by three nearby seismic stations, and the travel time variation at each station is estimated using the transfer function calculated from the recorded data. Long-term variations in Vp and Vs are observed and can be interpreted by the change in fluid saturation and crack density of the subsurface rocks. The variation in fluid saturation and crack density are consistent with that in the groundwater level, which is measured at the station nearest to the ACROSS. Short-term responses to rainfalls are observed at the station nearest to the ACROSS system; the interpretation of the changes in crack density and saturation is inconsistent with the ground water observation, partly owing to the initial response to rainfall. This can be interpreted as an air–water mixture within pores or cracks on a fine scale.

The present study was performed in order to determine the engineering geology and geotechnical details of soils and rocks along Tabriz Metro Line 2(TML2) by using the information and raw data which were acquired by borehole drilling and all field and laboratory tests in the study area. The minimum and maximum depths of the boreholes were 15 and 40 m, respectively. The results of their analysis revealed that geologically, the areas of metro route, mainly formed by alternating layers of claystone, siltstone, marl, and conglomerate, covered mainly by the alluvial deposits and in addition to older, dextral, strike-slip North Tabriz Fault (NTF) which is a major and most important geological structure of Tabriz area, there are also many minor and generally young and seismically active faults. The results of investigation on the groundwater depth in boreholes of TML2 also indicated that the groundwater depth varies between 1.5 and 30 m, along the route of metro. Eventually, based on the standard penetration test values (N-SPT), it was revealed that soils of the western parts of TML2 are in the group of dense to very dense, the central parts are in the group of very dense (Bazaar area) and dense (Fahmideh area), and the eastern parts are very dense. And finally the results achieved from determining groundwater sulfate values according to Concrete Code of Iran (CCI) indicated that the amount of soluble sulfate in the soil is mild to extremely high. Accordingly, the amount of sulfate increases from the western to the eastern parts. So that, this value is between 200 and 26,500 ppm. Based on these studies, the average of sulfate in the western, central and eastern parts is, respectively, 1118, 1275 and 4840 ppm. Thus, the groundwater in the east part is highly aggressive, and deterioration of concrete lining of the tunnel is expected in the near future.

Investigation of groundwater level is considered a prominent research topic for the study of underground hydrologic system. Due to the complexities of underground geological structure, the accuracy of real-time ground water level prediction is limited. In this study, a novel two-phase data-driven framework to model the time-series groundwater level with spatial–temporal analysis and least square support vector machine is proposed. Groundwater data collected from four monitoring sites in the northern region of United Kingdom is utilize in this study. In phase I, the time-series analysis is conducted to study the temporal characteristics of the groundwater. Based on the time-series analysis, least square support vector machine is performed to construct the prediction model to forecast the future groundwater level. In phase-II, the spatial correlation between the water levels in four sites are computed to construct a comprehensive model regarding the interrelation between the monitoring sites. Computational results illustrated the outperformance of least square support vector machine in predicting time-series groundwater levels compared with other state-of-arts machine learning algorithms. It has been demonstrated that the spatial–temporal model may serve as an applicable approach for the future research of groundwater resources.

This study analyzed the size of 172 rainfall-induced landslides in Taiwan during 2006–2012. Comparing the landslide size with rainfall conditions, this study found that large and deep landslides usually occurred due to long-duration and moderate-intensity rainfall (11.5–31.0 mm/h; 26.5–62.5 h), whereas small and shallow landslides occurred in a wide range of rainfall intensity and duration (8.5–31.0 mm/h; 4.0–62.5 h). This observation is ascribable to the fact that large and deep landslides need a high ground water level caused by a prolonged rainfall. Concerning the area of landslides, their frequency–area distribution correlates well with a power law relation having an exponent of −1.1 ± 0.07, over the range 6.3 × 102 to 3.1 × 106 m2. The slope of the power law relation for the size–frequency distribution of landslides in Taiwan is lower than those for other areas around the world. This indicates that for the same total area or total number of landslides, the proportion of large landslides is higher in Taiwan than in other areas.

Turkey is located in a tectonically active region. In the recent years, earthquakes occurred in settlement areas caused people dead and substantial damage to buildings. In order to reduce damages of possible earthquake effects on the buildings and people’s strengthening, the buildings and structuring in safer areas is increasingly gained importance. The Burdur city, situated at the tectonically active northeastern part of the Fethiye-Burdur Fault Zone (FBFZ), SW Turkey. This fault zone is approximately 300 km in length, and it contains several normal faults with left lateral oblique slip components. The Burdur settlement area is situated on the tectonically active fault segments of the FBFZ. This paper focuses on soil-structure interaction of existing buildings in Burdur settlement area built near the active FBFZ. In order to highlight the high risky, potentially risky, and low risky buildings for guiding decisions on retrofitting or renewal these buildings. In the study, to test and quantify the spatial distribution of the buildings built on the high or low liquefaction risk zones, the Getis-Ord Gi* statistics for hot and cold spot determination are applied to buildings which are weighted with the ground water level. According to results, the NE of the area buildings was built in high liquefaction prone areas. However, in the SW of the area buildings were built in low liquefaction prone areas. Other potentially risky areas located in the center of the area include those along some of the dried streams deposits, which produce the loose young soils that are particularly susceptible to liquefaction.

Soil liquefaction have been observed and documented at least eight times during moderate to larger magnitude historical and recent earthquakes in Hungary. Surface manifestations of liquefaction were reported from Komarom (1763, 1783, 1822), Mor (1810), Ermellek (1829, 1834), Kecskemet (1911) and Dunaharaszti (1956) earthquakes. In the study, we give a brief description of these earthquakes and make available reports that demonstrate the occurrence of soil liquefaction. Where available, we describe local subsoil conditions and information regarding ground water level. Distribution of horizontal ground accelerations possibly caused by these historical earthquakes has been modelled by ShakeMap program. Simulations indicate horizontal PGA of 0.2–0.3 g in areas where liquefaction occurred.

Most countries experience periodic dry spells/droughts and climatologists predict these may become more severe and of longer duration in the future. Whilst ground movement associated with shrink/swell is well known, other implications of changes in the general climatic conditions are less often considered by the construction industry. Having discussed the effect of shrink/swell in open field and wooded areas, the pressures involved in re-hydration, the significance of desiccation cracks for slope stability and the influence of dry and moist periods on road construction, the paper highlights how a change in ground water level and/or temperature can induce the development of ground sulphates and cause irreversible heave in lime-stabilised ground.

A World Bank-aided project on sodic land reclamation in Uttar Pradesh is being executed by U.P. Bhumi Sudhar Nigam, Lucknow, and Remote Sensing Applications Centre, U.P., Lucknow has the responsibility of sodic land mapping for the execution of land reclamation programme at the cadastral level. Sodic lands are mainly concentrated in the Gangetic alluvial plains but the problem of sodicity is particularly acute in the canal-irrigated areas. A study of the distribution pattern of sodic lands in canal and noncanal command areas in a reclamation site (covering 60 villages out of which sodic lands were mapped in 51 villages) of Etah district in Uttar Pradesh, indicates that 18.39 per cent area of the canal command villages was barren sodic which was 13.41 per cent of the total geographical area of the site (15417 ha), however, 11.69 per cent area was recorded to be barren sodic in the non-canal command villages which was only 3.16 per cent of the geographical area of the site. The results of soil chemical analysis indicate that barren sodic lands of canal command area are saline-sodic with higher concentration of soluble salts (pH2 >8.5, EC2 >4 dSm−1), however, those of non-canal command area are sodic (pH2 >8.5, EC2

This study investigates the variation of matrix suction, water content and ground water level before and after the rainfall for the unsaturated colluvium slope in the campus of Fuafan University. The measuring devices including electrical matrix suction, water content and ground water level were set up in different surface of planting condition for each depth in real-time. It is observed that the matrix suction in the time from July to September is higher; however, when heavy rains caused by typhoon happened, matrix suction will drop rapidly. This variation is obvious in short grass zone and less clear in the broadleaf tree zone. The maximum value in short grass zone, long grass zone and broadleaf tree zone at 2 m depth are 90.3, 68.2, 18.5 kPa, respectively. These results are expected to serve as a reference for the study of slope stability mechanisms.

Optimum ground-water conditions of a drained mass of a polder system having one conducting channel were simulated with account for a rain or snow fall-out. The calculations were conducted with the use of an invariant (independent of the number of conducting open channels and their configuration) nonstationary mathematical polder system, involving a strategy for control of the ground-water level in a drained mass (a system of Saint-Venant differential equations for an open channel, a two-dimensional Boussineq equation, and a differential equation for the transfer of water in drains were simultaneously solved).

In this paper we have analyzed precise gravity survey and gravity effects resulted from water loading, crustal deformation, ground water level change and precipitation before and after the water impoundment in the Three Gorges Reservoir. We found that: ① In dam area of the reservoir, gravity effect resulted from water load increase is the most significant, maximum gravity change is 200×10−3 m/s2, but this effect is limited in amplitude and range. Gravity change can be observed about 5 km offshore. The gravity change caused by ground water level change is regional; and the impact of precipitation on it should not be neglected. ② At head area of the reservoir, the maximum gravity change is near Xiangxi. Monitoring the variation of gravity field and further study should continue in the future.

Kuwait City is a Middle Eastern coastal city characterized by arid conditions with shallow, saline groundwater. As some parts of the new ring road development were below the ground water level, 5,000 anchors were incorporated in the design to restrain the road against hydrostatic uplift pressures. About 750 anchors were only partially completed when they were inundated with aggressive groundwater for a period of about 2 years when dewatering was temporarily abandoned as a result of the Gulf War in 1990. Subsequently, physical, metallurgical and strength tests were undertaken to assess both the degree of corrosion and the long-term integrity of these partially completed anchors. The paper discusses the testing, the remedial measures and the long-term monitoring system. It was decided to keep some of the dewatering wells as a precautionary standby in case of future problems.

Five geoelectric potential difference (electric field, here after) monitoring stations have been in operation since September 1997 in anarea near Liwa town, southern Sumatra, Indonesia, to examine the relationship between electric field changes and earthquakes. Short-term electric field variations were found to correspond mainly to geomagnetic activity, while long-term variation was mostly gradual shift and was clearly correlated neither precipitation nor ground water level variations. Co-seismic electric field changes ranging between 1 and 8 mV were observed for five mb > 5 earthquakes at multiple stations during September ∼ December 1997. The epicenters of the earthquakes were in the Indian Ocean within about 170 km from the monitoring sites.

The area of wet grasslands on peat soil in the Netherlands is slowly increasing at the expense of drained, agriculturally used grasslands. This study aimed (i) to assess the contribution of wet grasslands on peat soil to methane (CH4) emissions, and (ii) to explain differences among sites and between years in order to improve our understanding of controlling factors. For these purposes, a field study was conducted in the period 1994–1996 in the nature preserve Nieuwkoopse Plassen, which is a former peat mining and agricultural area. Net CH4 emissions were measured weekly to monthly with vented closed flux chambers at three representative sites, and at ditches near these sites. Three-years average of CH4 emissions was 7.9 g CH4 m- 2 yr-1 for Drie Berken Zudde, 13.3 for Koole, and 20.4 for Brampjesgat. Ditches near the sites emitted 4.2–22.5 g CH4 m-2 yr-1. The time-course of CH4 emissions for all experimental sites and years was fit with a multiple linear regression model with ground water level and soil temperature as independent variables. Lowering or raising the ground water level by 5 cm could decrease or increase CH4 emissions by 30–50%. Therefore, ground water level management of these grasslands should be done with care.

By using the precursory anomalies at fixed seismological stations or observational points in China, which are obtained every year from the Assembly of National Seismologic Consideration (ANSC) from 1988 to 1996, to study the relationship between the anomalies in a certain year and the earthquakes occurring in the Chinese mainland in the next year. Based on the anomalies before 84 moderate or large earthquakes, it is concluded that except for the means of ground water level, the anomalous ratios for the other six means of earthquake forecasting in seismic regions are smaller than that in aseismic regions or that in the whole mainland of China. The means which has the maximum anomalous ratio is the means of ground water level, and the regions where the maximum ratio is observed are Xinjiang Uygur Autonomous Region, Sichuan and Yunnan provinces. The means which have the second anomalous ratios are the hydrogeochemistry and deformation and the regions where the second ratio is obtained are Xinjiang Uygur Autonomous Region, Yunnan Province. The means which has the minimum ratio is geomagnetism, the regions where the minimum ratio is observed are Inner Mongolia Autonomous Region and South China. The composite nomalous ratios for all means are 26.85% in seismic regions, 25.11% in aseismic regions. The latter also is the background level of precursory anomalies in Chinese Seismological Network. The anomalous ratios are 26.30% for the earthquakes of M s about 5.0 within the range of 200 km distant from the epicenter, 29.19% for earthquakes about 6.0 within 300 km, and 29.44% for earthquakes about 7.0 within 500 km.

An electric pulse method of investigating subsurface nonuniformities on excessively moistened forest soils is proposed. An instrument designed to use this method in practice is described. The results of field tests are presented.

This review summarizes the result of the second round of nominations for the IASPEI Preliminary List of Significant Precursors. Currently this List contains five cases of precursors: (1) foreshocks, (2) preshocks, (3) seismic quiescence before major aftershocks, (4) radon decrease in ground water, and (5) ground water level increase. A list of four cases that could not be accepted nor rejected by the panels reviewing them contains three on crustal deformations and one on seismic quiescence. In the second round 10 nominations were evaluated, nine new ones and one which had been considered previously. Two were accepted for the List, two were placed in the category of undecided cases. To date, a total of 40 nominations have been evaluated by IASPEI. For 37 of these the nominations, the mail reviews, the panel opinions, and, where supplied, the author's reply were published. This evaluation process remains active throughout the International Decade for Natural Hazards Reduction. Additional nominations are invited.

Jharia coalfield, the chief storehouse of prime coking coal in India, has lost the original controls of ground water conditions. Here, ground water level is dependent mainly upon the presently existing topography, geomorphic features such as abandoned channels, confluence of channels, losing streams etc. and human-induced recharge conditions. These features are reflected by the soil moisture content and presence of vegetative cover. The ground water map of Jharia coalfield has been prepared from the aerial photographs using the grey tone and vegetation cover as the criteria. The observations are supported with field checks. The ground water map prepared will be very much useful to the society because some parts of the coalfield suffer from severe drought during summer.

The hydrogeomechanical problems of mining are considered, which deal with rocks and ground water as a single mechanical system. Among these problems are the openpits slopes stability, rocks consolidation and surface subsidence due to ground water level lowering, water inrushes into mine workings, rock bursts prevention by using the water injection into the advance boreholes, etc. The paper contains the basic theoretical grounds, as well as in-situ and laboratory methods for the investigation of these processes. The combined study of ground water regime and rock deformations has resulted in the theoretical substantiation of the hydrodynamic and geomechanical processes within the scope of unique scientific direction-hydrogeomechanics (Mironenko, 1974). The hydrogeomechanical models are widely used now for the analysis and forecasting the extremely important processes connected with the safe and efficient mining operations, as well as with the protection of geological medium. Among these processes are

This paper describes the observation of the structural behaviour of two of the largest docks in the world, the Setenave docks, as well as the experimental techniques developed by LNEC for observing this type of structures.

Okukubi Dam, planned for construction at the midportion of Okinawa Island, is the first concrete gravity dam to be built on the Quaternary limestone and calcareous sand formation in Japan. Principal characteristics of the dam are as given below

The Keban dam on the Firat was erected on a limestone ridge deeply karstified mainly by hydrothermal activity. Extensive highly interconnected percolation paths resulted in and below the dam foundation which convey inpounded water below the 250 m deep grouted cut-off into Keban Creek and to sources downstream of the dam. The cut-off, the cavern discovered after filling the lake and its treatment, the leakages before and after remedial measures were achieved, are presented.

In the arid climate of the tropics, there is, as well as the climate-type of soil, an intrazonal soil over Ca-rich mother rock, while in the plains there is a tendency for silicic acid rock soils to be formed. A high ground water level leads to the formation of amphi-percolative alkali soils, and finally in the pans exo-percolative salt soils form. All these soils show different profiles, different chemical reactions and different percolation direction. In the young state, they all have a basic reaction, which, however, can become acid in the endo-percolative types during the process of development, while this change only begins in the amphi-percolative alkali soils when degradation sets in. All these soils have very different values agriculturally, and they must therefore in any case be kept distinct and must not all be lumped together under the name of “alkali soils”.

The author examines the effect of infiltration, acting on a strip, on the ground water level for unbounded and semibounded one-dimensional flow models, when the soil is homogeneous and the impermeable horizon has a slight tilt.

The conference, in which information was exchanged on current developments in the theory and practice of electokinetic solidification of weak soils, discussed plans for the development of an efficient method of electrokinetic solidification of weak margine soils. More than 20 papers were presented on various aspects of marine muddy sediments which included factors such as the constant electrical field on clay soil, physiomechanical and chemical properties, the use of autoclave water glass for soil solidification, electrosilicatization for the solidification of loess and quick sand below ground water level, increase of strength, and chemical solidifying additives.