A probabilistic approach for estimating return period of extreme annual rainfall in different cities of Punjab

Multi-day rainfall events are an important cause of recent severe flooding in Pakistan, and any change in the magnitude of such events may have severe impact upon urban structures such as dams, urban drainage systems, and flood. This article uses statistical distributions to define extremes of annual rainfall of different cities of Punjab (Lahore, Murree, Sialkot, and Jhelum) with given return periods. Our calculations suggest that general extreme value is the best-fitted distribution for the extreme annual rainfall of different cities of Punjab. Our calculations show that different cities of Punjab have 5 years return period for receiving more than 100 mm daily rainfall. While they have 30 years return period for receiving more than 200 mm daily rainfall. This asks for construction of new dams in Pakistan.     

Utilization of effective period of roughness to distinguish different types of waves

In a continuation of the preceding paper (p. 1150–1157) this article deals with discrimination against multiples, again employing the CDR technique. Simple and practical relations are developed. The basis of discussion is a comparison of the multiple raypath with the apparent one. — A. J. Hermont.     

Origin and distribution of different types of sinkholes in the plain areas of Southern Italy

Sinkholes constitute a significant risk in many karst areas, and may even threat human safety. Collapse sinkholes that occur catastrophically without showing premonitory signs may result in severe economic losses and casualties. In the last years, research on sinkholes and related detrimental effects has significantly increased in Italy, in the aftermath of remarkable events.

Aimed at analysing the peculiar conditions which lead to sinkhole occurrence in Southern Italy, a set of cases in the plain areas of Campania, Apulia and Calabria is discussed. The considered regions show a wide variety of environmental conditions. In Campania, the plains are underlain by alluvial deposits with intercalations of volcaniclastic sediments. Sinkholes are generally located along the Tyrrhenian margin of the carbonate massifs or within intramontane Apennine basins. In Apulia, a flat and elongated peninsula, most of the cases occur on calcarenites overlying limestone bedrock along the coast. In Calabria, one of the most seismogenic Italian regions, the surveyed cases seem to be attributable mainly to earthquake-induced liquefaction.

The article provides a first glance on the variety of sinkholes in the plain areas of Southern Italy, to highlight the possibility of further subsidence events in the considered regions, as well as in other comparable areas of the country.     

Multivariate analysis of heavy metal pollution in street dusts of Xianyang city, NW China

Urban street dust is one of important indicators of the status of urban environmental pollution. There are many studies in capital cities, but little attention has been paid to this kind of study in medium cities, especially in China. The dust samples were collected in the district of traffic crossroads in Xianyang city, Shaanxi Province. Pb, Cd, Cu, Ni, Zn, Cr and Mn concentrations were determined by using atomic absorption spectrometry. The results indicate that street dusts in Xianyang city have elevated metal concentrations as a whole in comparison with Shaanxi Province soil, except for Mn. The content of heavy metals was comparable to those in capital cities. Correlation coefficient analysis, principal component analysis and cluster analysis were used and three main sources were identified; Mn comes mainly from soil sources; Cu, Zn and Ni are mainly derived from industrial sources combined with traffic sources; Pb, Cr and Cd have traffic sources. Heavy metal enrichment factors were calculated, which can reflect human influence degree of street dusts.     

Pumpellyites and coexisting minerals in different low-grade metamorphic facies of Liguria, Italy

Pumpellyite from four-phase assemblages (pumpellyite + epidote + prehnite + chlorite; pumpellyite + epidote + actinolite + chlorite; pumpellyite + epidote + Na-amphibole + chlorite, together with common excess phases), considered to be low variance in a CaO-(MgO + FeO)-Al₂O₃-Fe₂O₃ (+Na₂O + SiO₂+ H₂O) system, have been examined in areas which underwent metamorphism in the prehnite-pumpellyite, pumpellyite-actinolite and low-temperature blueschist facies respectively. The analysed mineral assemblages are compared for nearly constant (basaltic) chemical composition at varying metamorphic grade and for varying chemical composition (basic, intermediate, acidic) at constant metamorphic conditions (low-temperature blueschist facies). In the studied mineral assemblages, coexisting phases approached near chemical equilibrium. At constant (basaltic) bulk rock composition the MgO content of pumpellyite increases, and the X_Fe3+ of both pumpellyite and epidote decreases with increasing metamorphic grade, the Fe³⁺ being preferentially concentrated in epidote. Both pumpellyite and epidote compositions vary with the bulk rock composition at isofacial conditions; pumpellyite becomes progressively enriched in Fe and depleted in Mg from basic to intermediate and acidic bulk rock compositions. The compositional comparison of pumpellyites from high-variance (1–3 phases) assemblages in various bulk rock compositions (basic, intermediate, acidic rocks, greywackes, gabbros) shows that the compositional fields of both pumpellyite and epidote are wide and variable, broadly overlapping the compositional effects observed at varying metamorphic grade in low-variance assemblages. The intrinsic stability of both Fe- and Al-rich pumpellyites extends across the complete range of the considered metamorphic conditions. Element partitioning between coexisting phases is the main control on the mineral composition at different P-T conditions.     

Characterization of the subsurface urban heat island and its sources in the Milan city area,Italy

Urban areas are major contributors to the alteration of the local atmospheric and groundwater environment. The impact of such changes on the groundwater thermal regime is documented worldwide by elevated groundwater temperature in city centers with respect to the surrounding rural areas. This study investigates the subsurface urban heat island (SUHI) in the aquifers beneath the Milan city area in northern Italy, and assesses the natural and anthropogenic controls on groundwater temperatures within the urban area by analyzing groundwater head and temperature records acquired in the 2016–2020 period. This analysis demonstrates the occurrence of a SUHI with up to 3 °C intensity and reveals a correlation between the density of building/subsurface infrastructures and the mean annual groundwater temperature. Vertical heat fluxes to the aquifer are strongly related to the depth of the groundwater and the density of surface structures and infrastructures. The heat accumulation in the subsurface is reflected by a constant groundwater warming trend between +0.1 and?+?0.4 °C/year that leads to a gain of 25 MJ/m² of thermal energy per year in the shallow aquifer inside the SUHI area. Future monitoring of groundwater temperatures, combined with numerical modeling of coupled groundwater flow and heat transport, will be essential to reveal what this trend is controlled by and to make predictions on the lateral and vertical extent of the groundwater SUHI in the study area.

     

Landslides types controlled by tectonics-induced evolution of valley slopes (Northern Apennines,Italy)

This paper investigates the role played by geomorphological and tectonic processes affecting a portion of an active mountain belt in causing the occurrence of different types of landslides developed in flysch bedrock. The adopted multidisciplinary approach (geomorphology, geology and geophysics) allowed to recognize in a portion of the Northern Apennines of Italy different types of landslides that developed in response to slope dynamics, in turn dependent on broader regional-scale tectonic processes. Sedimentary bed attitude, local tectonic discontinuities and lithology only partially influenced the type of landslides, which have been deeply affected by the activity of regional-scale antiform that controlled the hillslope geomorphic evolution in different ways. The growth of this structure and the tilting of its forelimb produced gently dipping slopes that approached the threshold angle that can cause the occurrence of (mainly) translational rockslides. Conversely, high-angle normal faulting parallel to the antiform axis (related to a later stage of activity of the antiform itself) strongly controlled the stream network evolution and caused the watercourses to deeply incise portions of their valleys. This incision produced younger steep valley slopes and caused the development of complex landslides (roto-translational slides-earth/debris flow). The results of the integrated study presented in this paper allowed to distinguish two main types of landslides whose development reflects the events that led to the geomorphological and geological evolution of the area. In this perspective, within the study area, landslides can be regarded and used as indicators of broader-scale recent tectonic processes.     

Comparison of size effect for different types of strength tests

SummaryComparison of Size Effect for Different Types of Strength Tests Different theories have been proposed to explain and predict size effect. Notable is Weibull's Weakest link theory. In addition various theories have been founded on strain energy consumption at failure. The present paper suggests a theoretical approach, based on energy considerations and mode of failure, which holds for diverse types of mechanical testing. Maximum size effect is assumed to be associated with failure through development of a single fracture plane and a lack of size effect is associated with failure affecting a volume of material. The quantitative expression of the theoretical approach is based on the relationship between load at failure (P) and cross sectional area of the specimen (A):P=KA ⁿ wheren expresses size effect andK is a constant.The theoretically lowestn-value equals 0.75 expressing maximal size effect whereas the theoretically highestn-value is 1.00 expressing lack of size effect.n-values evaluated from published data for various mechanical tests indeed lie between these limits and appear to be related to type of test, material properties and specimen shape. Point load tests and Brazilian tests are generally associated with large size effects. This may be attributed to the test conditions which promote development of single fracture planes. On the other hand relatively small size effects are generally found for uniaxial compression tests. Failure in these tests characteristically occurs through multiple fracturing and crushing and therefore affects a volume of material rather than a single plane. Brittleness seems to be associated with large size effects and ductility with small size effects.With 4 Figures     

Hazard appraisal and hazard-zone mapping of flooding and debris flowage in the Rio Combeima valley and Ibague city,Tolima Department,Colombia

Since a state law issued in 1989, every big town in Colombia has to promote its own preparedness programme for disaster relief in the framework of the Oficina Nacional para la Atencion de Desastres (1987). Such a programme includes a very detailed hazard-zone map for flooding and debris flows in the densely inhabited suburbs of Ibagué city (capital of Tolima Department), as well as enquiries about risk knowledge and consciousness among people who live at high risk. We stress the fact that both detailed hazard-zone maps and enquiries should be closely undertaken at the same time, and that distinguishing previous knowledge, existing consciousness and risk perception to forecast the behaviour of people and of the community in case of disaster, are criteria for a better risk assessment.     

Multivariate statistical analysis for the assessment of groundwater quality under different hydrogeological regimes

Multivariate statistical analysis has been widely used for hydrogeochemical characterization of groundwater quality. In this study, hydrochemical data from three hydrological basins were used and two methods (factor and cluster analyses) were applied. The first area is the coastal area of Eastern Thermaikos Gulf where groundwater is influenced by seawater intrusion and geothermal fluids. The other two areas are the inland basins of Gallikos and Perdikas in which agricultural and industrial activities constitute the main anthropogenic pollution sources of groundwater. Initially, the aforementioned methods were applied for each area separately and resulted in a different number of significant factors and clusters, while the natural and anthropogenic influences were spatially determined in each area. Additionally, factor and cluster analyses were applied coupling data from all areas. Therefore, five clusters and three major factors were determined distinguishing the hydrochemical processes and impacts from anthropogenic activities in more detail. It is worth mentioning that the application of cluster analysis in the coupled groundwater samples of all studied areas resulted beneficially in the most hydrochemically complex area. Salinization dominates in the coastal area, while in Gallikos and Perdikas basins high concentrations of NO₃ occur mainly due to agricultural activities and small livestock units. The numerous hydrochemical samples are identified as the main issue for the higher discretization and reliability of the second approach. Nevertheless, this study is associated with a number of limitations of multivariable statistical analysis regarding extreme concentrations of Cl and Na. This issue stimulates further research in overcoming and understanding these drawbacks.     

Heavy metals in sediments from different environments of a northern Adriatic Sea area,Italy

Sediments from different environments of an area directly affected by the discharge of the Po River and 13 other minor rivers have been studied. Three main sources of metals and several distribution mechanisms can be identified. Concentration profiles of metals in a core allow one to establish background levels of finegrained sediments for Cd, Hg, Pb, and Zn Seabed sediments do not appear to be very polluted, mainly because of desorption and dilution processes     

安徽池州南郊地下水水化学类型的演化与成因

通过对安徽池州南郊地下水调查及样品测试分析,发现近22年来该地区地下水水化学类型已由简单变为复杂.与1990年比,2012年HCO3-Ca和HCO3-Ca+ Mg型地下水分布面积显著缩小,HCO3-Na+ Ca型地下水完全消失,HCO3 +SO4-Ca型地下水出现并大面积分布.认为造成这种现象的主要原因是该地区近年来酸雨频发及工矿企业污染物排放.     

Beachrock as evidence of sea-level lowstand during the classical period,Parion antique city,Marmara Sea,Turkey

Results obtained from beachrock lying on the north coast of the antique city of Parion in Çanakkale province, NW Turkey, are presented based on field data, petrographic analyses, cement fabrics, and radiocarbon dating. Extending to 20?m offshore at a depth of ?2?m, the studied 50-cm thick beachrock is poorly sorted lithic sandstone. Both exposed and submerged parts are characterized by sequentially precipitated marine phreatic and vadose cements composed of micrite encrustations with micro-organism borings, pseudopeloidal aggregates of high-Mg calcites with scalenohedral habits and meniscus bridges. Radiocarbon ages point to a deposition during the classical period when the sea level was below (between ?1 and ?1.5?m) that of the present. The beachrock witnesses a granule- and pebble-dominated wide beach prior to cementation, suggesting that Parion’s fortification walls were behind the coastline during this lowstand and raises questions concerning the existence of a harbor north of the city.     

Combining Arc-GIS and OWA model in flooding potential analysis (case study: Meshkinshahr city)

Natural Hazards - “Streets have been turned into rivers”; this is a news headline which we have been hearing more often recently and refers to the floodwaters flowing into cities....     

海岸带城市地下水分布特征

我国城市海岸带地下水类型和分布主要受控于陆地地质作用,尤以大地构造作用和河流地质作用为主导。松散沉积物类海岸带地下水为孔隙水,含水介质单一,空间变化大,地下水的赋存和分布规律亦相应复杂。以距今78万年晚更新世为界线,可将第四纪松散沉积物含水层组划分为上（浅）下（深）两层（部）。下部的全新统（Q4）和上更新统（Q3）含水岩组以微咸水、咸水多见;上部的中更新统（Q2）和下更新统（Q1）分布有淡水,部分地下淡水资源有一定的供水意义。基岩类海岸带地下水主要为裂隙水和岩溶水,多为淡水,其水资源量与当地的降水量和基岩入渗系数的大小有直接关系。除砂砾石台地的基岩类海岸带、少数溺谷型泥质海岸带的河谷内和碳酸盐岩分布区外,一般无集中供水意义。     

Multivariate analysis to investigate Cl distribution in rocks from different settings

Chlorine concentration has been determined by chemical methods in 97 samples of basic rocks collected at Etna volcano (Sicily, Southern Italy), Sao Miguel (Azores Islands), and Lanzarote (Canary Islands). The samples have been processed together with data related to specific magmatic and tectonic conditions, drawn from the literature. Thus, the contents of SiO₂, K₂O, and P₂O₅ of 228 samples have been used to investigate Cl distribution in the considered environments, using principal component analysis. The log-centered variance-covariance matrix has been processed in order to overcome the closure constraints. The results indicate that a clear distinction between continental and oceanic regions can be obtained in the components space. A preliminary discriminant diagram involving chlorine thus can be proposed.     

Multivariate statistical comparison of Northern Apennines Paleozoic sequences: a case study for the formations of Monti Romani (Southern Tuscany-Northern Latium,Italy)

The Paleozoic quartzites and graphite-rich metapelites cropping out in the area of Monti Romani, in Central Italy, show very common mineralogical and petrographical features and are lacking of fossils. For this reason, their stratigraphic attribution in the general picture of the Tuscan Paleozoic is still debated.In this work 23 rock samples have been analyzed for major and trace (Li, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ag, Ba, La, Ce and Pb) elements, in order to give a contribution to their stratigraphic interpretation. Using linear discriminant analysis (LDA) on major elements, the paleozoic formations of Monti Romani have been compared with 4 “reference groups”, representing the formations of: (1) Cambro-Ordovician; (2) Middle Ordovician; (3) Late Ordovician-Silurian; (4) Permo-Carboniferous age, cropping out in Tuscany (in total 136 samples).The application of LDA to real geological data is generally limited by (a) the deviation of the data from the normal (Gaussian) distribution model, which is an important basic assumption of LDA, and (b) the closure of compositional data (e.g., major elements sum to 100), which can induce false correlations between elements. With regards to both problems, the log-ratio transformation of the data suggested by Aitchison has resulted in a satisfactory solution for the application of LDA.The results of LDA show that most Paleozoic formations of Monti Romani closely resemble the Tuscan Permo-Carboniferous formations: the samples are in fact attributed to this group with probability ranging from 0.632 to 0.995. Only the data of the “Valle Tegolaie Carbonatic-Phyllitic Complex” give contradictory indications; this unit is in fact believed to be Devonian in age, on the basis of field evidence, and should be eventually compared with the other Silurian-Devonian formations of the Northern Apennines.Correlations between elements have been studied with the Spearman rank correlation coefficient ϱ, which is much less influenced by the non-normal distribution of the data than the Pearson coefficientr. The analysis of the Spearman's matrix allowed some inferences about mineralogy. The high correlation of Fe_tot and Na with K, Al and LOI should account for a phengitic-paragonitic composition of sericite. The same mineral strongly controls the distribution of most trace elements, namely Li, Ni, Rb, Sr, Y, Nb, Ag, Ba, La and Ce (coefficients between 0.600 and 0.877). In contrast, low coefficients for Cu, Pb and, to minor extent Zn, suggest that other minerals such as graphite or sulphides are probably important for the distribution of these elements. In the same way, Zr does not show any significant correlation, as expected, being concentrated mainly in the granoblastic layers (detrital zircon).     

Radon level in different types of underground buildings in China

Total and bioavailable concentrations of rare earth elements （REEs） in the latesol of Hainan Province, China, were measured by ICP-MS, and the distribution characteristics of REEs were discussed in various latesol profiles. The results show that the total concentrations of REEs were higher than the average statistical data of the whole China. The correlation coefficients between the total and bioavailable concentrations of REEs were from 0.66 to 0.95 （P〈0.001, n=63）. This suggests that it is necessary to study the bioavailable and total heavy metal concentrations in soils in order to assess the ecological and environmental effects, and to provide scientific information on REEs application as micro-elemental fertilizers, and consequently their potential health risks. The percentage of the bioavailable concentrations in the latesol derived from some kinds of parent materials was up to 50%, indicating that it was unnecessary to apply REE micro-elemental fertilizers in the soils.