An empirical method to estimate shear wave velocity of soils in the New Madrid seismic zone

In this study, a set of charts are developed to estimate shear wave velocity of soils in the New Madrid seismic zone (NMSZ), using the standard penetration test (SPT) N values and soil depths. Laboratory dynamic test results of soil samples collected from the NMSZ showed that the shear wave velocity of soils is related to the void ratio and the effective confining pressure applied to the soils. The void ratio of soils can be estimated from the SPT N values and the effective confining pressure depends on the depth of soils. Therefore, the shear wave velocity of soils can be estimated from the SPT N value and the soil depth. To make the methodology practical, two corrections should be made. One is that field SPT N values of soils must be adjusted to an unified SPT N′ value to account the effects of overburden pressure and equipment. The second is that the effect of water table to effective overburden pressure of soils must be considered. To verify the methodology, shear wave velocities of five sites in the NMSZ are estimated and compared with those obtained from field measurements. The comparison shows that our approach and the field tests are consistent with an error of less than of 15%. Thus, the method developed in this study is useful for dynamic study and practical designs in the NMSZ region.     

Seismic Site Classification and Correlation between Standard Penetration Test N Value and Shear Wave Velocity for Lucknow City in Indo-Gangetic Basin

Subsurface lithology and seismic site classification of Lucknow urban center located in the central part of the Indo-Gangetic Basin (IGB) are presented based on detailed shallow subsurface investigations and borehole analysis. These are done by carrying out 47 seismic surface wave tests using multichannel analysis of surface waves (MASW) and 23 boreholes drilled up to 30 m with standard penetration test (SPT) N values. Subsurface lithology profiles drawn from the drilled boreholes show low- to medium-compressibility clay and silty to poorly graded sand available till depth of 30 m. In addition, deeper boreholes (depth >150 m) were collected from the Lucknow Jal Nigam (Water Corporation), Government of Uttar Pradesh to understand deeper subsoil stratification. Deeper boreholes in this paper refer to those with depth over 150 m. These reports show the presence of clay mix with sand and Kankar at some locations till a depth of 150 m, followed by layers of sand, clay, and Kankar up to 400 m. Based on the available details, shallow and deeper cross-sections through Lucknow are presented. Shear wave velocity (SWV) and N-SPT values were measured for the study area using MASW and SPT testing. Measured SWV and N-SPT values for the same locations were found to be comparable. These values were used to estimate 30 m average values of N-SPT (N ₃₀) and SWV (V _s ³⁰ ) for seismic site classification of the study area as per the National Earthquake Hazards Reduction Program (NEHRP) soil classification system. Based on the NEHRP classification, the entire study area is classified into site class C and D based on V _s ³⁰ and site class D and E based on N ₃₀. The issue of larger amplification during future seismic events is highlighted for a major part of the study area which comes under site class D and E. Also, the mismatch of site classes based on N ₃₀ and V _s ³⁰ raises the question of the suitability of the NEHRP classification system for the study region. Further, 17 sets of SPT and SWV data are used to develop a correlation between N-SPT and SWV. This represents a first attempt of seismic site classification and correlation between N-SPT and SWV in the Indo-Gangetic Basin.     

Ultrasonic measurements of Vp and Qp: relaxation spectrum of complex modulus on basalt melts

Ultrasonic compressional wave velocity V_p and quality factor Q_p have been measured in alkali basalt, olivine basalt and basic andesite melts in the frequency range of 3.4–22 MHz and in the temperature range of 1100–1400°C. Velocity and attenuation of the melts depend on frequency and temperature, showing that there are relaxation mechanisms in the melts. Complex moduli are calculated from the ultrasonic data. The results fit well a complex modulus of Arrhenius temperature dependence with log-normal Gaussian distribution in relaxation times of attenuation. The analysis yields average relaxation time, its activation energy, relaxed modulus, unrelaxed modulus and width of Gaussian distribution in relaxation times. Relaxed modulus is smaller (17.5 GPa) for basic andesite melt of high silica and high alumina contents than for the other two basalt melts (18.1–18.4 GPa). The most probable relaxation times decrease from ～ 3 × 10^?10 s for basic andesite to ～ 10^?11 s for alkali basalt at 1400°C. Activation energies of attenuation, ranging from 270 to 340 kJ mol^?1 in the three melts, are highest in basic andesite. Longitudinal viscosity values and their temperature dependences are also calculated from V_p and Q_p data. The volume viscosity values are estimated from the data using the shear viscosity values. Longitudinal, volume and shear viscosities and their activation energies are highest in the basic andesite melt of the most polymerized structure.     

Liquefaction assessments using seismic piezocone penetration (SCPTU) test investigations in Tangshan region in China

Shear wave velocity (V_s) measurements from seismic piezocone penetration (SCPTU) soundings have been increasingly used for site characterization and liquefaction potential assessments. Several sites in Tangshan region, China liquefied during the Tangshan earthquake, M_w=7.8 in 1976 and these sites were characterized recently using the SCPTU device. Other sites in the same region where liquefaction was not observed are also included in the present field investigations. Three liquefaction assessment models-based on measured shear wave velocity, shear modulus and tip resistance parameters of SCPTU are evaluated in this paper for their accurate predictions of liquefaction or non-liquefaction at the test sites. Analyses showed that the shear wave velocity—liquefaction resistance model with normalized overburden vertical stress have yielded a success rate of 78% in predicting liquefied site cases and another similar approach with mean stress based normalization has a success rate of 67%. The correlation of q_c/G_o-CRR_7.5 based on geological age has correctly assessed the liquefaction potential at most sites considered in this research. Overall, all three models based on shear wave velocity, shear modulus and cone tip resistance are proven valuable in the assessments of liquefaction at the present test sites in the Tangshan region.     

An experimental investigation of the Hashin-Shtrikman bounds on two-phase aggregate elastic properties

Existing data supporting or disputing the validity of the Hashin-Shtrikman bounds on the elastic properties of multiphase aggregates often do not consider porosity, elastic anisotropy, or experimental errors. In this experiment, two-phase aggregates of KCl + (NH₄Br, TlBr, CsCl, NaCl, Cu, and LiF) at every 20% volume fraction were vacuum hot-pressed and the compressional and shear velocities were measured with a computer-controlled ultrasonic interferometer to ±0.2%. The ratio of the shear moduli, μ, (phase 2/KCl) varied from about 1 to 5, producing a range of separations between the theoretical two-phase Hashin-Shtrikman bounds for the composites. Samples were generally 99% or better of the theoretical density, with less than 1% velocity anisotropy. Porosity corrections were applied assuming spherical pores, based on the observed velocity-pressure behaviour. Velocities agreed with the HS bounds calculated from the end-member single-crystal stiffnesses when anisotropy was taken into account.The velocity data were also used to estimate the bulk modulus, K, and shear modulus of the second phase by means of the matrix method — taking the K and μ of KCl as known and calculating the moduli of the other phase assuming that the measured velocities were the two-phase Hashin-Shtrikman bounds or the Voigt-Reuss-Hill average. A narrow range of moduli estimates results only if the μ's of both phases are fairly closely matched. For μ's mismatched by a factor of 5, the theoretical uncertainty in the estimates can be 10 times larger than the experimental uncertainty. Estimates using the VRH average can lie outside the HS-based results.     

On Poisson's ratio and composition of the Earth's lower mantle

Poisson's ratio of the lower mantle, calculated from recently published values of seismic wave velocities and extrapolated to atmospheric pressure and room temperature is found to be in the range 0.23 ⩽ ν ⩽ 0.25. These values are compared with the values of Poisson's ratio calculated for binary mixtures of MgSiO₃ perovskite and magnesiowüstite with various iron contents. Current values of the experimental error on measured elastic moduli give little hope to be able to discriminate between pyrolite and chondritic lower mantles: both are acceptable if the shear modulus of perovskite is in the upper range of Liebermann et al. estimates. A similar calculation using the seismic parameter φ confirms the results obtained by considering Poisson's ratio and further constrains the value of the shear modulus of perovskite to lie between 1600 and 1700 kilobars for current mantle models to remain plausible. Chemical stratification of the mantle is, therefore, possible but not required by seismological data.     

Empirical shear wave velocity equations in terms of characteristic soil indexes

An investigation to systematize empirical equations for the shear wave velocity of soils was made in terms of four characteristic indexes. The adopted indexes are the N-value of the Standard Penetration Test, depth where the soil is situated, geological epoch and soil type. As some of these indexes are variates belonging to interval scales while others belong to nominal or ordinal scales, the technique known as a multivariate analysis cannot be employed. A new approach to the theory of quantification, after C. Hayashi, was introduced and developed for solving this difficulty. Fifteen sets of empirical equations to estimate low strain shear wave velocity theoretically may be obtained by combining the above four indexes. All of these sets were derived by use of about 300 data, and their accuracies were evaluated by means of correlation coefficients between the measured and estimated shear wave velocities. The best equation was found to be the one which included all the indexes, and its correlation coefficient was 0.86. The empirical equation relating the standard penetration N-value to the shear wave velocity provided a correlation of only 0.72, and is one of the lowest ranking among the 15 sets of equations.     

Data modeling and assimilation studies with the MU radar

We report initial results of data modeling and assimilation studies for several MU radar experiments. Various inputs to a one-dimensional ionospheric model are adjusted to provide agreement with observation and also to learn the sensitivity of the model to their variations. Certain observations are also used directly in the model to anchor or constrain its behavior. In particular, studies of the electron density from 100 to 500 km altitude in the ionosphere are carried out with the help of a theoretical model of O⁺, NO⁺, O⁺₂ and N⁺₂ densities and MU radar observations of the power, ion-drift and plasma-temperature profiles. Four typical cases are selected to study quantitatively the effects of the (A) perpendicular-north component of the plasma drift (15 December 1986), (B) atmospheric composition (7 October 1986), (C) solar EUV flux (2 August 1989) and (D) upper-boundary O⁺ density (5 October 1989) on the model N_mF2, h_mF2 and N_e profile, as well as on the neutral wind calculation from h_mF2 and drift data. It is found that the measured vertical ion drift explains quantitatively well the measured h_mF2 (particularly at low solar activity) while the model gives a better match with the measured N_e when it uses the h_mF2-based wind rather than the measured plasma drift. Different model values of the atmospheric O/N₂ ratio and EUV flux and different values of the upper-bound O⁺ density may modify not only N_mF2 markedly but also h_mF2: a lower O/N₂ ratio results in higher h_mF2; the EUVAC model gives higher h_mF2 at high solar activity than does the EUV91 model; with a smaller upper-bound O⁺ density, h_mF2 is lower by day but little changed by night. We specifically note that the meridional wind needed by the model to reproduce the observed h_mF2 differed according to how well the model reproduced the observed N_mF2. The uncertainties in the MSIS86 and EUV model predictions are also discussed. It is found that if the MSIS and EUV91 models are used together, the model gives an N_mF2 higher than that measured at high solar activity. Thus the O/N₂ ratio needs to be reduced from the MSIS value if EUV91 is used. If EUVAC is used, no large modification is required. At equinox for low solar activity, modeling with either EUV model produces N_mF2 values lower than those measured, and so the true O/N₂ ratio may be higher than that given by MSIS model.     

Soil characterization using electrical resistivity tomography and geotechnical investigations

Electrical Resistivity Tomography (ERT) has been used in association with Standard Penetration Test (SPT) and Dynamic Cone Penetration Test (DCPT) for Geotechnical investigations at two sites, proposed for thermal power plants, in Uttar Pradesh (UP), India. SPT and DCPT tests were conducted at 28 points and two ERT profiles, each measuring 355 m long, were recorded using 72 electrodes deployed at 5 m spacing. Electrical characterization of subsurface soil was done using borehole data and grain size analysis of the soil samples collected from boreholes. The concept of electrical resistivity variation with soil strength related to the grain size distribution, cementation, porosity and saturation has been used to correlate the transverse resistance of soil with the number of blow counts (N-values) obtained from SPT and DCPT data. It was thus observed that the transverse resistance of soil column is linearly related with the number of blow counts (N-values) at these sites. The linear relationships are site-specific and the coefficients of linear relation are sensitive to the lithology of subsurface formation, which was verified by borehole data. The study demonstrates the usefulness of the ERT method in geotechnical investigations, which is economic, efficient and less time consuming in comparison to the other geotechnical methods, such as SPT and DCPT, used for the purpose.     

Nonlinear Three-dimensional Inversion of Low-frequency Scattered Elastic Waves

—We investigate a new nonlinear inversion method for low frequencies to determine the bulk and shear modulus as well as the material density and the location of subsurface inhomogeneities. The solution is a direct exact nonlinear inversion of single scattered waves containing near- and far-field terms for incident P and scattered P and S waves, allowing for inversion of parameters in the vicinity and at distance from the sources and receivers. Because the approach is based on single scattering theory, the range of application includes single strong scattering anomalies of various sizes like magma chambers, gas- or fluid-filled cavities, or buried near-surface obstacles. The replacement of the material properties by a new set of parameters, referred to as scattering factors, allows the inverse problem to be solved analytically. The nonlinear nature of the scattering problem is investigated and implications for the inversion process are discussed. The deviations in the elastic parameters as a function of the scattering factors show a strong asymmetry about zero, and therefore linearized approximations will perform differently, depending on the sign of the perturbation. Based on the low frequency (Rayleigh) approximation, we introduce and evaluate a pair of approximations (Mie) derived by numerical and analytical integration of the Rayleigh approximation. Both approximations are based on the underlying principle of subdividing the inhomogeneities into a number of small noninteracting parts and subsequent integration over the total volume, thus increasing the Rayleigh limit and producing better resolution of the parameter estimates during the inversion. The two Mie approximations, when evaluated as a function of scattering angle and distance, produce similar results in the mid- and far-field of the inhomogeneity and reveal better resolution than the Rayleigh approximation. For three anomalies of ± 50% in bulk modulus, shear modulus, and density, the relative error between the exact solution and the two Mie approximations remains below 10%, 20%, and 30%, respectively, for values of k _p R < 3.0, where R is the radius of the heterogeneity. However, smaller errors for individual cases are found for values up to k _p R≈ 4.5. The performance of the inversion based on the analytically and the numerically integrated Mie approximation is tested for single parameter perturbations, revealing reliable and stable inversion results for the bulk and the shear modulus, reasonable results for the density, and crosstalk between the shear modulus and the density. The results show well-defined locations of the anomalies and slight deviations in the estimates of their magnitudes, which can be explained by amplitude and phase deviations between the analytical solution used for forward modeling and the approximations used for the inversion. The analytical Mie approximation provides a fast means to estimate elastic parameters compared to the more time consuming numerically integrated approximation, while the latter can be applied to more arbitrarily shaped inhomogeneities.     

Evaluation of shear wave velocity profile using SPT based uphole method

The uphole method is a field seismic test which uses receivers on the ground surface and an underground source. A modified form of the uphole method is introduced in order to obtain efficiently the shear wave velocity (V_S) profile of a site. This method is called the standard penetration test (SPT)-uphole method because it uses the impact energy of the split spoon sampler in the SPT test as a source. Since the SPT-uphole method can be performed simultaneously with the SPT test it is economical and not labor intensive compared to the original uphole methods which use small explosives or a mechanical source. Field testing and interpretation procedures for the proposed method are described. To obtain reliable travel time information of the shear wave, the first peak point of the shear wave using two component geophones is recommended. Through a numerical study using the finite element method (FEM), the procedure of the proposed method was verified. Finally, the SPT-uphole method was performed at several sites, and the field applicability of the proposed method was verified by comparing the V_S profiles determined by the SPT-uphole method with the profiles determined by the downhole, the spectral analysis of surfaces waves (SASW) method and from the SPT-N values.     

The effect of wave-induced turbulence on intertidal mudflats: Impact of boat traffic and wind

Semi-diurnal and fortnightly surveys were carried out to quantify the effects of wind- and navigation-induced high-energy events on bed sediments above intertidal mudflats. The mudflats are located in the upper fluvial part (Oissel mudflat) and at the mouth (Vasière Nord mudflat) of the macrotidal Seine estuary. Instantaneous flow velocities and mudflat bed elevation were measured at a high frequency and high resolution with an acoustic doppler velocimeter (ADV) and an ALTUS altimeter, respectively. Suspended particulate matter concentrations were estimated by calibrating the ADV acoustic backscattered intensity with bed sediments collected at the study sites. Turbulent bed shear stress values were estimated by the turbulent kinetic energy method, using velocity variances filtered from the wave contribution. Wave shear stress and maximum wave–current shear stress values were calculated with the wave–current interaction (WCI) model, which is based on the bed roughness length, wave orbital velocities and the wave period (T_S). In the fluvial part of the estuary, boat passages occurred unevenly during the surveys and were characterized by long waves (T_S>50 s) induced by the drawdown effect and by short boat-waves (T_S<10 s). Boat waves generated large bottom shear stress values of 0.5 N m⁻² for 2–5 min periods and, in burst of several seconds, larger bottom shear stress values up to 1 N m⁻². At the mouth of the estuary, west south-west wind events generated short waves (T_S<10 s) of H_S values ranging from 0.1 to 0.3 m. In shallow-water environment (water depth <1.5 m), these waves produced bottom shear stress values between 1 and 2 N m⁻². Wave–current shear stress values are one order of magnitude larger than the current-induced shear stress and indicate that navigation and wind are the dominant hydrodynamic forcing parameters above the two mudflats. Bed elevation and SPM concentration time series showed that these high energy events induced erosion processes of up to several centimetres. Critical erosion shear stress (τ_ce) values were determined from the SPM concentration and bed elevation measurements. Rough τ_ce values were found above 0.2 N m⁻² for the Oissel mudflat and about 1 N m⁻² for the Vasière Nord mudflat.     

On estimating the hydraulic properties of soil,Part 2. A new empirical equation for estimating hydraulic conductivity for sands

A new empirical equation to estimate hydraulic conductivity is proposed, based on a large set of measured data for hydraulic properties of soil. The equation is simpler and more accurate than the series-parallel model. Under conditions of insufficient data, the new equation provides a good estimation of hydraulic conductivity for sands. For the same class of soils, another empirical equation is proposed to estimate the power N in the Averjanov-Irmay function.     

Liquefaction potential and strain dependent dynamic properties of Kasai River sand

The availability of efficient numerical techniques and high speed computation facilities for carrying out the nonlinear dynamic analysis of soil-structure interaction problems and the analysis of ground response due to earthquake loading increase the demand for proper estimation of dynamic properties of soil at small strain as well as at large strain levels. Accurate evaluation of strain dependent dynamic properties of soil such as shear modulus and damping characteristics along with the liquefaction potential are the most important criteria for the assessments of geotechnical problems involving dynamic loading. In this paper the results of resonant column tests and undrained cyclic triaxial tests are presented for Kasai River sand. A new correlation for dynamic shear damping (D_s) and maximum dynamic shear modulus (G_max) are proposed for the sand at small strain. The proposed relationships and the observed experimental data match quite well. The proposed relationships are also compared with the published relationships for other sands. The liquefaction potential of the sand is estimated at different relative densities and the damping characteristics at large strain level is also reported. An attempt has been made to correlate the G_max with the cyclic strength of the soil and also with the deviator stress (at 1% strain) from static triaxial tests.     

Fractal analysis of experimentally generated pyroclasts: A tool for volcanic hazard assessment

Rapid decompression experiments on natural volcanic rocks mimick explosive eruptions. Fragment size distributions (FSD) of such experimentally generated pyroclasts are investigated using fractal geometry. The fractal dimension of fragmentation, D, of FSD is measured for samples from Unzen (Japan) and Popocatépetl (Mexico) volcanoes.Results show that: (i) FSD are fractal and can be quantified by measuring D values; (ii) D increases linearly with potential energy for fragmentation (PEF) and, thus, with increasing applied pressure; (iii) the rate of increase of D with PEF depends on open porosity: the higher the open porosity, the lower the increase of D with PEF; (iv) at comparable open porosity, samples display a similar behavior for any rock composition.The method proposed here has the potential to become a standard routine to estimate eruptive energy of past and recent eruptions using values of D and open porosity, providing an important step towards volcanic hazard assessment.     

Constitutive model for soil amplification of ground shaking: Parameter calibration,comparisons, validation

A one-dimensional constitutive model, developed for the nonlinear ground response analysis of layered soil deposits, is calibrated and validated experimentally in this paper. The small number of parameters renders the model easily implementable, yet quite flexible in effectively reproducing almost any type of experimentally observed hysteretic soil behavior. In particular, the model generates realistic shear modulus and damping curves as functions of shear strain, as well as stress–strain hysteresis loops. The model is calibrated against three sets of widely-used published shear modulus and damping (G : γ and ξ : γ) curves and a library of parameter values is assembled to facilitate its use. The model, along with a developed explicit finite-difference code, NL-DYAS, for analyzing the wave propagation in layered hysteretic soil deposits, is tested against established constitutive models and numerical tools such as Cyclic1D [12] and SHAKE [42], and validated against experimental data from two centrifuge tests. Emphasis is given on the proper assessment of the V_s profile in the centrifuge tests, on the role of soil nonlinearity, and on comparisons of two inelastic codes (NL-DYAS and Cyclic1D) with equivalent linear (SHAKE) analysis.     

Predicted and measured electron density at 600 km altitude in the South American peak of the equatorial anomaly

Measurements of the electron density at 600 km altitude (N₆₀₀) were obtained with the Hinotori satellite launched by the Institute of Space and Astronautical Science of Japan. These measurements were used to check the validity of the International Reference Ionosphere (IRI) model in predicting the electron density at that altitude in the South American peak of the equatorial anomaly. The measurements correspond to the longitude zone from 285 to 369° and −15° geomagnetic latitude. To model the electron density at 600 km altitude, two cases were considered, namely (i) N₆₀₀ was calculated with the IRI model at 10° intervals within the corresponding longitudinal zone and mean values were obtained, and (ii) N₆₀₀ was calculated with the IRI using ionosonde data as input coefficients in the model. The data used for this study were measured almost simultaneously with the total electron content data used in a previous work. The results show good predictions at hours of minimum ionisation for the equinox and the December solstice. For the June solstice, the best agreement was obtained around noon. However, strong disagreements were observed in some cases such as the equinox at 15:00 LT, suggesting that there is a need to improve the modeled topside profile.     

Elasticity of polycrystalline stishovite

Ultrasonic data for the velocities of SiO₂-stishovite have been determined as a function of pressure to 10 kbar at room temperature for polycrystalline specimens hot-pressed at pressures P = 120kbar and temperatures T = 900°C. These cylindrical specimens are 2 mm in diameter and 0.9–1.4 mm long and have a grain size less than 10 μm. Compressional and shear wave velocities were measured both parallel and perpendicular to the axis of pressing and were found to be isotropic at 10 kbar with ν_p = 11.0 ± 0.2km/sec andν_s = 6.9 ± 0.3km/sec; this shear velocit is substantially higher than that of Mizutani et al. (1972) perhaps due to the presence of crack orientations in their specimen which affected ν_s but not ν_p. The Murnaghan P-V trajectories calculated from the ultrasonic data [bulk modulus K_s = 2.5 ± 0.3Mbar and assuming (?K_s/?P)_T = 6 ± 2] are consistent with recent hydrostatic compression data and with the shock wave compression data above 600 kbar. The combined evidence from the data of the ultrasonic and hydrostatic compression techniques suggests that the most probable value of the bulk modulus of stishovite at zero pressure is close to the upper limit of the uncertainty of our ultrasonically determined value, K₀ = 2.7?2.8Mbar. Elasticity data for rutile-type oxides are not compatible with normal K_s-V₀ systematics perhaps due to the neglect of non-central forces in the lattice model. These new stishovite data would make it impossible to satisfy the elasticity-density data of the lower mantle using an oxide mixture with either olivine or pyroxene stoichiometry.     

Correlations Between Shear Wave Velocity and In-Situ Penetration Test Results for Korean Soil Deposits

Shear wave velocity (V _S) can be obtained using seismic tests, and is viewed as a fundamental geotechnical characteristic for seismic design and seismic performance evaluation in the field of earthquake engineering. To apply conventional geotechnical site investigation techniques to geotechnical earthquake engineering, standard penetration tests (SPT) and piezocone penetration tests (CPTu) were undertaken together with a variety of borehole seismic tests for a range of sites in Korea. Statistical modeling of the in-situ testing data identified correlations between V _S and geotechnical in-situ penetration data, such as blow counts (N value) from SPT and CPTu data including tip resistance (q _t), sleeve friction (f _s), and pore pressure ratio (B _q). Despite the difference in strain levels between conventional geotechnical penetration tests and borehole seismic tests, it is shown that the suggested correlations in this study is applicable to the preliminary determination of V _S for soil deposits.     

Velocity and Density Heterogeneities of the Tien-Shan Lithosphere

—The Tien-Shan orogene is a region in which the earth’s crust undergoes considerable thickening and tangential compression. Under these conditions the lithosphere heterogeneities (composi tion, rheological) create the prerequisites for the development of various phenomena of tectonic layering (lateral shearing, different deformation of layers). To study the distribution of velocity, density and other elastic parameters, the results from a seismic tomography study on P-wave as well as S-wave velocities were used. Using empirical as well as theoretical formulas on the relationship between velocity, density and silica content in rocks, their distribution in the Tien-Shan’s lithosphere has been calculated. In addition, other elastic parameters, such as Young’s modulus, shear modulus, Poisson’s ratio and coefficient of general compressions have been determined. Zoning of different types of crust was carried out for the region investigated. The characteristics of the "crust-mantle" transition have been investi gated. Large blocks with different types of the earth’s crust were distinguished. Layers with inverse values of velocity, density and shear and Young modulus are revealed in the Tien-Shan lithosphere. All of the above described features open new ways to solve geodynamics problems.