Relationship between magnetic parameters and heavy element contents of arable soil around a steel company, Nanjing

Magnetic parameters and element contents were determined in core NJ008 collected from the uppermost ca. 40 cm in a steel company in southwest Nanjing. The results showed that magnetic susceptibility (χ), saturation isothermal remanent magnetization (SIRM) and anhysteretic remanent magnetization (ARM) were enhanced in the uppermost 20 cm, with a mean magnetic susceptibility value of 112.5×10-8 m3 kg-1. Below 20 cm, χ decreased sharply with a mean value of 27.8×10-8m3 kg-1. Low-coercivity minerals such as magnetite dominate in arable soils, while the relative content of antiferromagnetic minerals increases below 20 cm. Heavy metals (Ni, Cu, Fe, Pb, V, and Zn) have similar vertical trends as χ. Principal component analysis reveals common high loadings of the same factor for magnetic concentration parameters (χ, ARM, and SIRM) and elements (Ni, Cu, Fe, Pb, V, and Zn) with an excellent linear correlation (0.69≤R≤0.98) between them. Magnetic susceptibility of paddy soil core NJ013, which had the same parent material as NJ008 but was far from pollution sources, showed stable values of magnetic concentration parameters along the whole core. Absolute values correspond to the so-called magnetic background value (below 20 cm) of NJ008. This indicates that pesticide and fertilizer had little effect on magnetic signals of the upper part of core NJ008 and the extremely enhanced magnetic concentration parameters originate from the steel company emission. Although, the arable soil does not reveal the pollution history and transportation due to annual ploughing, the significant linear relationship between magnetic concentration parameters and heavy metal contents suggests that magnetic parameters can serve as a proxy for quickly detecting soil metallic pollution and estimating the extent of contamination.     

Magnetic characteristics of dustfall in urban area of north China and its environmental significance

Urban particulate pollutants not only affect urban air quality but also directly threaten public health. Lanzhou has been one of the most seriously polluted cities in the world due to its special geophysical location and weather conditions, which makes it an ideal place for urban particulate pollution study. In this study a set of environmental magnetic parameters (χlf, χfd%, χARM, SIRM, HIRM, SOFT and back field IRM) were measured and analyzed for the dustfall samples collected monthly during 1997.4―2000.5 and 2004.11―2005.10 at Lanzhou University campus (KLD and CCS) and at a clear site of Gaolanxian (GLX). Results demonstrate that the main magnetic minerals in the dustfall are magnetite, with some maghaemite and haematite. Cross plots of Mrs/Ms vs. Bcr/Bc and χfd% vs. χARM/SIRM indicate that the main magnetic grain sizes are pseudo-single-domain (PSD). The high concentration of magnetic min-erals in the dustfall indicates that Lanzhou is seriously polluted. The main pollution sources are an-thropogenic activities and nature dust, with the former posing a great threat during the whole year, which is different from the general view that the natural dust is the main contributor in summer. With great efforts of the government and local authority in the past decades, the air quality in Lanzhou has been improved in winter, but it is not so obvious in summer. This study also reveals that as a simple, rapid and accurate technology, environmental magnetism could be a valuable tool for urban pollution study.     

Loess magnetic properties in the Ili Basin and their correlation with the Chinese Loess Plateau

Over the past two decades, magnetoclimatological studies of loess-paleosol sequences in the Chinese Loess Plateau (CLP) have made outstanding achievements, which greatly promote the understanding of East Asian paleomonsoon evolution, inland aridification of Asia, and past global climate changes. Loess magnetic properties of the CLP have been well studied. In contrast, loess magnetic properties from outside the CLP in China have not been fully understood. We have little knowledge about the magnetic properties of loess in the Ili Basin, an intermontane depression of the Tianshan (or Tien Shan) Mountains. Here, we present the results of rock magnetic measurements of the Ili loess including mass magnetic susceptibility (χ) and anhysteretic remanent magnetization (ARM), high/low temperature dependence of susceptibility (TDS) and hysteresis, as well as X-ray diffraction (XRD) for mineral analysis. Based on the comparison with loess-paleosol sequences in the CLP (hereafter referred to as the Chinese loess), we discuss the possible magnetic susceptibility enhancement mechanism of the Ili loess. The results show that 1) the total magnetic mineral concentration of the Ili loess is far lower than that of the Chinese loess, though they have similar magnetic mineral compositions. The ferrimagnetic minerals in the Ili loess are magnetite and maghemite, and the antiferromagnetic mineral is hematite; XRD analysis also identifies the presence of ilmenite. The ratio of maghemite is lower in the Ili loess than in the Chinese loess, but the ratios of magnetite and hematite are higher in the Ili loess than in the Chinese loess. 2) The granularity of magnetic minerals in the Ili loess, dominated by pseudo-single domain (PSD) and multi-domain (MD) grains, is generally much coarser than that of the Chinese loess. Ultrafine pedogenically-produced magnetic grains have a very limited contribution to the susceptibility enhancement. Rather, PSD and MD particles of magnetite and maghemite are the main contributors to the enhancement of susceptibility in the Ili loess. 3) The susceptibility enhancement mechanism for the Ili loess is complicated and superimposes both a wind velocity/vigor model (Alaskan or Siberian model) and the in situ ultrafine grain pedogenic model; the former might play an important role in the Ili loess. 4) Magnetic susceptibility enhancements of the Ili loess are related not only to the eolian input of the source area, but also to the local climate, landform, and geological background. Therefore, great care should be taken when reconstructing paleoclimate using magnetic susceptibility data from the Ili loess.     

THE EQUIVALENT SLOPE - A NEW METHOD FOR CALCULATING SOIL LOSS FROM IRREGULAR SLOPES

he slopes in field conditions are always irregular, but the supposed uniform slopes are used in most erosion models. Some studies used several uniform slopes to approximate an irregular slope for estimating soil erosion. This approximation is both time-consuming and weak in physical insights. In this paper, the concept of equivalent slope is presented based on that runoff potential on uniform slope is equal to that of irregular slope, and the equivalent uniform slope is used to estimate soil erosion instead of the irregular slopes. The estimated results of slope-length factors for convex and concave slopes are consistent with those from the method of Foster and Wischmeier, The experiments in the southern part of the Loess Plateau in China confirmed the applicability of the present method. The method is simple and has, to some extent, clear physical meanings, and is applicable for estimating soil erosion from irregular slopes.     

Magnetostratigraphic and paleoclimatic studies on the Red Earth Formation from the Chengdu Plain in Sichuan Province,China

Two red earth sections from the Chengdu Plain in Sichuan Province are dated using geomagnetic methods. The Brunhes/Matuyama (B/M) reversal boundary is recognized within the upper parts of the two sections,and the Jaramillo normal subzone occurs in the middle-lower parts of the vermiculated red soil (VRS),which indicate that the parent material for the VRS deposited in the middle Quaternary. Sedimentologic and geochemical studies suggest that the Chengdu Clay and part of the parent material for the VRS are of aeolian origin. Pollen analysis indicates that the Chengdu Plain was mainly covered by needle-leaved forest with a cool to cool temperate humid climate when the parent material for the VRS deposited. The relatively cool to cool temperate climatic condition in the Chengdu Plain in the middle Quaternary,which may be caused by the uplift of the Tibetan Plateau,was a response to the geo-environmental changes of global significance.     

Wavefield continuation datuming using a near surface model

When topography and low velocity zone differences vary greatly, conventional vertical static time shifts will cause wavefield distortion and influence wave equation seismic imaging for seismic data acquired on a complex near surface. In this paper, we propose an approach to datum correction that combines a joint tomography inversion with wavefield continuation to solve the static problem for seismic data on rugged acquisition topography. First, the near surface model is obtained by refracted wave tomography inversion. Second, the wavefield of sources and receivers are continued downward and upward to accomplish datum correction starting from a flat surface and locating the datum above topography. Based on the reciprocal theorem, Huygens＇ and Fresnel principles, the location of sources and receivers, and regarding the recorded data on the surface as a secondary emission, the sources and receivers are upward-continued to the datum above topography respectively. Thus, the datum correction using joint tomography inversion and wavefield continuation with the condition of a complex near surface is accomplished.     

Magmatism and tectonic processes in Area A hydrothermal vent on the Southwest Indian Ridge

The hydrothermal vent in Area A(37.78°S,49.65°E)is the first active hydrothermal vent discovered on the Southwest Indian Ridge(SWIR).Heat source and adequate bulk permeability are two necessary factors for the formation of a hydrothermal vent.Along the SWIR 49.3°E to 51.2°E,the gravity-derived crustal thickness is up to 9.0 km,much thicker than the average thickness of the global oceanic crust.This characteristic indicates that the magma supply in this area is robust,which is possibly affected by a hotspot.The large-scale residual mantle Bouguer anomalies(RMBA)reveal prominent negative-gravity anomalies between the first-order ridge segment(from Indomed to Gallieni,46.0°E to 52.0°E)and the Marion-Del Cano-Crozet region.These anomalies indicate the channel of the hotspot-ridge interaction.The tomography data corrected with theoretical thermal model indicate that the low-velocity anomalies corresponding to this channel can reach the base of the lithosphere.Near the hydrothermal vent area,the topography and crustal thickness at the off-axis area are extremely asymmetrical.South of the SWIR,the high topography corresponds to the thinning crustal thickness.The residual isostatic topography anomalies indicate that Area A is a deviation from the local isostatic equilibrium,similar to the characteristics of the transform fault inside corner.The forward profiles of the magnetic data indicate that the thinning magnetic layer at the south side of Area A corresponds to the shallow,high-velocity area revealed by the OBS,which is the result of tectonic extension of a detachment fault.The active tectonic processes in Area A can provide sufficient crustal permeability to the hydrothermal circulation and may form massive sulfide deposits.     

The effects of plant density of Melastoma malabathricum on the erosion rate of slope soil at different slope orientations

Malaysia’s cut slopes,especially for road lines accommodation,are prone to erosions and landslides.These problems mainly occur due to lack of vegetation cover and strong erosive forces.In addition,the topography factors have also become a major factor affecting soil degradation.Thus,this study is aimed at determining the effects of planting density of a selected species,namely Melastoma malabathricum;one,two,and three seedlings per box,on the erosion rate at selected slopes of different orientation(morning and evening sun) at the Guthrie Corridor Expressway,Selangor.In six months of observation,treatment with three seedlings/box on the morning sun slope showed a lower erosion rate by 69.2%than those with the same treatment on the evening sun slope.In addition,the treatment of the three seedlings recorded at month six(final observation) had the highest reduction of soil saturation level(STL),by 23.6%.Furthermore,the physiological values of the species studied,grown on the morning sun slope,were higher in terms of stomatal conductance and photosynthetic rate by 12.1%and 15.8%(three seedlings/box),respectively.The overall results showed that plant density was inversely related to the STL and erosion rate on the slope.In conclusion,a planting density of three seedlings/box and morning sun orientation gave positive effects on the plant’s physiological performance of the slope,reducing the STL,as well as alleviating the erosion rate of slope soils.     

Estimating seismic moments and Lg Q using Lg spectra

A multi-event and multi-station inverse method is presented in the paper to simultaneously estimate the seismicmoments (Mo) and source comer frequencies (fc) of several Jiashi (Xinjiang, China) earthquakes, as well as theapparent Lg Q models for the paths from Jiashi to eight seismic stations (WMQ, AAK, TLG MAKZ, KUR, VOS,ZRN and CHK) in Central Asia. The resultant seismic moments correlate well with the Mo values obtained by Harvard University using the centroid moment tensor (CMT) inversion and the surface-wave magnitudes as well. Afterthe correction by a typical value of average radiation coefficient for regional SV waves, the Mo values from Lgspectral inversion are still close to the corresponding values obtained from CMT inversion. The obtained apparentQOLg values (Lg Q at 1 Hz) are consistent with the tectonic features of corresponding propagation paths. The QoLgvalues are 351±87, 349±86 and 300±27 for the paths from Jiashi to AAK, TLG and MAKZ, respectively. They aresmaller than QoLg values for the paths to KUR, VOS, ZRN and CHK, which are 553±72, 569±58, 550±57 and603±65, respectively. These results agree with the condition that the paths to AAK, TLG and MAKZ mainlypropagate through the mountainous Tianshan area where relatively strong seismic activities and large variations oftopography are exhibited, while the paths to KUR, VOS, ZRN and CHK mainly propagate through the stable areaof Kazak platform. The QoLg value for the path to WMQ is 462±56. This is also in agreement with the conditionthat the path to WMQ is basically along the border area between Tianshan Mountain and Tarim Basin, and alongthis path the variations of topography and crustal thickness are moderate in comparison with that along the path toMAKZ.     

Effects of Integrated Exploration in Hydrocarbon-Prospective Areas of South China

The complicated topography, morphology and geology are characteristic of South China, where the frequently covered waters and igneous bodies and widely exposed carbonates are difficult to seismic survey. This paper describes the effect of combining exploration of gravitational, magnetic and electric methods in the complicated hydrocarbon areas in South China by some case histories. Many year‘‘s exploration practices in the exploring areas of more than 20 show that the non-seismic integrated (gravity/magnetic/electric) geophysical prospecting can play an important role not only in regional assessment, basin optimization and early basin evaluation,but also in finding objective of low resistance in areas of exposed carbonate with high resistance, contouring local structure, outlining igneous body and reef, and differentiating rock facies of basement. The results of the non-seismic integrated geophysical survey have pointed out the direction for deploying next prospecting in the specific areas of South China and the valuable experiences have been accumulated to carry out hydrocarbon-hunting in the future.     

Statistical characteristics of the equatorial boundary of the nightside auroral particle precipitation

Based on the auroral electron/ion precipitation boundary database observed by the DMSP satellites during 1984–2009, the characteristics of the nightside equatorial boundaries of the electron precipitation(B1E) and the ion precipitation(B1I) in the Northern/Southern Hemispheres(NH/SH) are statistically investigated. The results show: That most of the boundaries are located between magnetic latitude(MLAT) of 60°–70° with the mean MLAT for B1E/B1 I to be 64.30°N/63.22°N and 64.48°S/63.26°S in the NH and SH, respectively, indicating that B1 E and B1 I in both hemispheres are located in conjugated magnetic field lines with B1 E ~1.2° poleward of B1I; that the MLAT of B1 E and B1 I in both hemispheres shift to lower MLAT(from ~70° to ~55°) as geomagnetic activity increases; that MLAT of both B1 E and B1 I and their differences slowly decrease from dusk to midnight with some difference in both hemispheres during different levels of geomagnetic activities; that B1 E and B1 I in both hemisphere decrease linearly with Kp and exponentially with Dst, AE, and SYM-H, respectively, demonstrating that auroral particle precipitation is closely related with geomagnetic activity; that in different magnetic local time(MLT) sectors, the changing rates of the boundaries with Kp are different, and the rates of B1 E are generally larger than that of B1 I, implying that the difference between B1 E and B1 I reduce with increasing geomagnetic activity. Compared with previous studies, the statistical results based on the long-term large database in this paper can well reflect the properties of the equatorial boundaries of auroral precipitation and may be used for physical modeling or space weather forecasting in future.     

Rock-magnetic properties of Neogene sediments, northern flank of Tianshan Mountains

Analyses of rock-magnetic properties of Neogene sediments of the Taxihe section, northern Tianshan Mountains, show that the section can be classified into three categories including lacustrine facies, fluvial facies and alluvial facies, which correspond to the lower, middle and upper of the Taxihe section respectively. The magnetic minerals of the lacustrine facies may be affected by the process of weath- ering, lithogenesis and biolithogenesis besides the source of the sediments. The natural remanence intensities are between 10-3 A/m and 10-2 A/m. The minerals are dominated by magnetite and the high coercive magnetic mineral may be goethite. The magnetic grains are the mixture of PSD SD or SD SP. The natural remanence intensities of the strata of fluvial facies are between 10-2 A/m and 10-1 A/m, about ten times that of the lacustrine facies. The magnetic minerals are mainly magnetite and hematite, and the magnetic grains are mainly PSD. The characteristic remanence (ChRM) carriers are magnetites. In the alluvial facies, the natural remanence intensities are mostly less than 1×10-2 A/m. The magnetic minerals of the series are dominated by magnetite and hematite, almost the same as the fluvial facies. But the difference is that most of the stepwise demagnetization can reveal two components and the ChRM carriers are hematites. The magnetic grains are PSD in terms of the hysteresis parameters.     

New insights on the age of the Mengyejing Formation in the Simao Basin,SE Tethyan domain and its geological implications

Knowledge on the origin and mechanism of the large potash formation in the southeast Tethyan tectonic domain are still under debate,one of which mainly due to the controversial ages of the potash-bearing strata.Here we present a detailed detrital zircon U-Pb geochronologic-magnetostratigraphic study of the potash-bearing Mengyejing(MYJ)Formation(Fm)from the Simao Basin.948 paleomagnetic cores and 4 detrital zircon U-Pb samples were collected from a 932-m thick Jiangcheng section.Thermal demagnetization isolated 857 primary characteristic remnant magnetization(ChRM)directions,indicated by positive reversals and fold tests and petrologic examinations.Seven normal and seven reversed polarity zones were identified and correlated well with chrons C27r to C34n of the geomagnetic polarity timescale(GPTS2012),yielding the first known age sequence of>112 to~63 Ma for the MYJ Fm.The ages for the potash bearing strata in the Simao commenced~20 Ma earlier than those in the adjacent Khorat basins,opposite to the traditional viewpoint that the former would rather correspond to the middle and lower parts of the latter.Given the paleogeographic reconstruction of likely a pan-Simao-Khorat basin during the Cretaceous,~85 Ma would be another important potential period for future potash exploration in the Simao Basin.     

Portable rainfall simulator for plot-scale investigation of rainfall-runoff,and transport of sediment and pollutants

A low-cost, simple to use portable rainfall simulator is developed for use over a 5 m^2 plot. The simulator is easy to transport and assemble in the field, thereby allowing for necessary experimental replicates to be done. It provides rainfall intensities of between 20 and 100 mm/h by changing the number and type of silicon nozzles used. The Christiansen coefficient of uniformities obtained in the field are appropriate and vary from 79 to 94% for rainfall intensities ranging from 30 to 70 mm/h. In addition, the median volumetric drop diameters measured for rainfall intensities of 30, 50, and 70 mm/h are in the lower range of that of natural rainfall and equal to 1.10 ± 0.08,1.69 ± 0.21, and 1.66 ± 0.20 mm, respectively. The velocities of the raindrops with diameters less than 1.2 mm reached terminal velocities, while raindrops less than 2.0 mm achieved velocities reasonably close to the terminal velocity of natural rainfall. Furthermore,the average time-specific kinetic energy(KET) for rainfall intensities of 30, 50, and 70 mm/h are 257.7,760.1, and 1645.2 J/m^2/h, respectively accounting for about 78.0 and 86.5% of the KET of natural rainfall for50 and 70 mm/h rainfall intensity, respectively. The applicability of the portable rainfall simulator for herbicide transport study is investigated using two herbicides(atrazine and metolachlor); herbicide losses in runoff and sediment samples are in the ranges reported in the literature. As a percentage of the amount of herbicide applied, 5.29% of atrazine and 2.15% of metolachlor are lost due to combined water and sediment runoff. The results show that the portable rainfall simulator can be effectively used in studying processes such as pesticide runoff, infiltration mechanisms, and sediment generation and transport at a field plot scale with an emphasis on how surface characteristics such as slope and soil properties affect these processes.     

Rock magnetic properties and palaeomagnetic results of sediments from a stone implement layer in the Bose Basin,Guangxi

Directional samples were taken to study rock magnetism and palaeomagnetic records from the Dong- sheng profile, which is 5 m thick and on the northwest edge of the Bose Basin. Mineralogy and rock magnetism of typical samples indicate that coarse granular titanomagnetite, and fine-grained hematite, superparamagnetic maghemite formed by pedogenesis are in the sediment, which has undergone many transformative processes during different stages of pedogenesis. Parallel samples were taken for thermal demagnetization (TH) (0 to 680℃) and alternating field (AF) demagnetization (0 to 80 mT) respectively. Experimental results of these two kinds of demagnetization illustrate that there are two or more magnetic components in the samples. Intensity of NRM decreases by almost 60% to 90% rapidly when the temperature ranges from 100℃ to 350℃, with a steady magnetic component. It is impossible to analyze the magnetic components at high temperature because those fluctuate widely when the temperature is higher than 400℃. Steady magnetic components from 100℃ to 350℃ indicate that the remanence was mainly carried by fine-grained hematite formed by pedogenesis, reflecting a change in the geomagnetic field while the magnetite was being oxidized into hematite by chemical weathering after deposition. The formative age of the sediments cannot be obtained by magnetic methods in this profile.     

Kinematic source model for simulation of near-fault ground motion field using explicit finite element method

1 Introduction The prediction of broadband near-fault ground motion is an important aspect of seismic risk analysis, and is essential for the evaluation of urban seismic safety. Many methodologies are used to model the near-fault ground motions, such as the Green function method, ?nite element (FE) / ?nite difference (FD) method and a hybrid method (Aagaard, 1999; Oprsal and Zahradnik, 2002; Oprsal et al., 2003 a and b). In the hybrid method, the FE / FD method is used to model the low fr…     

Discovery and implications of catenary-bead subaqueous dunes

Measurements of topography at the segment of bifurcation between the South Channel and North Channel in the Yangtze Estuary were conducted, and a new type of subaqueous dune was discovered. This structure, newly defined as a catenary-bead dune, consists of a catenary dune and its associated elliptical pit bedform. Based on this finding, the nomenclature of "morphology of dune associated with accompanying bedform" is first proposed. The measured data indicate a mean height and wavelength of 1.29 m and 31.89 m, respectively; wavelength/height ratio(L/H) of 14 to 56; and elliptical pits of mean and maximum depth 0.98 m and 1.98 m, respectively. Flow information was obtained using an Acoustic Doppler Current Profile(ADCP), and the bed material components were gathered with a bottom sampler. The results show mean flood and ebb velocities of 0.27 and 0.78 m s?1, respectively, with shorter duration of flood tide than ebb tide. The silt, very fine sand, and fine sand fractions were within the ranges 21.6–23.4%, 28.2–32.2%, and 39.7–41.6%, respectively, revealing complex bed material composition. Water depth at the study site varies from 13 to 17 m. This finding will enrich the study of dunes and provide important data for geomorphological research. Moreover, the results are significant for engineering applications to estuaries.     

Converted-wave Seismology in Anisotropic Media Revisited, Part I： Basic Theory

We have developed new basic theories for calculating the conversion point and the travel time of the P-SV converted wave (C-wave) in anisotropic, inhomogeneous media. This enables the use of conventional procedures such as semblance analysis, Dix-type model building and Kirchhoff summation, to implement anisotropic processing, and makes anisotropic processing affordable. Here we present these new developments in two parts: basic theory and application to velocity analysis and parameter estimation. This part deals with the basic theory, including both conversion-point calculation and moveout analysis.Existing equations for calculating the PS-wave (C-wave) conversion point in layered media with vertical transverse isotropy (VTI) are strictly limited to offsets about half the reflector depth (an offset-depth ratio, x/z, of 0.5), and those for calculating the C-wave traveltimes are limited to offsets equal to the reflector depth (x/z=1.0). In contrast, the new equations for calculating the conversion-point extend into offsets about three-times the reflector depth (x/z=3.0), those for calculating the C-wave traveltimes extend into offsets twice the reflector depth (x/z=2.0). With the improved accuracy, the equations can help in C-wave data processing and parameter estimation in anisotropic, inhomogeneous media.     

The elusive mantle dynamic topography

The Earth's surface is characterized by a bi-modal distribution of topography,where continents on average are about 5 km higher than the ocean basins.This basic topographic property of the planet Earth could be intuitively explained by isostasy,in that the felsic・to・intermediate continental crust is thick(~40 km)and light(~2.8 g/cm3)while the mafic oceanic crust is thin(〜7 km)and dense(〜3 g/cm3).There are also large-scale topographic variations within continents and oceans,which could also be attributed to isostasy:the former is usually due to lateral variation in crustal thickness and the latter to different ages of the seafloor.Since it seems isostasy works just fine for most large-scale topographic features on Earth,why do we bother to further introduce dynamic topography?     

Site amplification in the Lijiang Valley, Yunnan Province

The site amplifications for three stations, Libin (LIBI), Baisha (BASH) and Yulong (YULG) situated respectively in the southern, middle and northern parts of Lijiang Valley, are obtained by analyzing the S-wave soil/bedrock and microtremor horizontal/vertical spectral ratios. The data are digital recordings for the aftershocks of the Lijiang MS=7.0 earthquake on February 3, 1996. In the frequency range of 1～4 Hz, the S-wave soil/bedrock spectral ratio of E-W component for LIBI is the largest and amounts to 4.5. The microtremor soil N-S/vertical (V) spectral ratio is approximate to 1, E-W/V is about 4.5 and the same with above soil/bedrock spectral ratio. It is shown that the vertical and N-S components of microtremor have not been amplified by the soil and the spectral ratios for BASH and YULG are further evaluated. They have similar characteristics with that of LIBI. In above frequency range, both N-S/V ratios are approximate to 1, while the E-W/V ratio is about 6 for BASH, 4.5 for YULG. Lijiang Valley is characterized by the trans-valley directional site response.