Mineralogical Characterization of Aeolian Sands from Inner Mongolia, China

Aeolian sand sample from Tengger desert, located in the southern part of Inner Mongolia (China) was characterized for major elemental composition and mineralogy by EPMA, XRF and XRD methods. The objective of this research was to provide data which would be a guide to aid future beneficiation of this sand, especially for the economic exploitation of feldspar and quartz which have a wide range of applications in various industries like plastic, paint, ceramics and glass industries. The elemental analysis of the sample was carried out by X-ray fluorescence spectrometer and chemical analysis while the minerals present were identified by an X-ray diffraction analyzer. The sand was discovered to contain basically SiO2 (82.43%), Al2O3 (7.68%), Na2O + K2O (4.37%) and TiO2 and Fe2O3 as the main impurities. It was also discovered that grinding of the sand is required to enhance the liberation of the minerals and the separation methods recommended are magnetic separation and flotation. It was therefore concluded that aeolian sand is a suitable source of quartz and feldspar for use in the industry.

On the realization of seismic microzonation of Almaty (Kazakhstan) in ground accelerations based on the “continual” approach

Seismic microzonation for Almaty city for the first time use probabilistic approach and hazard is expressed in terms of not only macroseismic intensity,but also Peak Ground Acceleration(PGA).To account for the effects of local soil conditions,the continual approach proposed by A.S.Aleshin[1,2]was used,in which soil coefficients are a function of the continuously changing seismic rigidity.Soil coefficients were calculated using the new data of geological and geophysical surveys and findings of previous geotechnical studies.The used approach made it possible to avoid using soil categories and a jump change in characteristics of soil conditions and seismic impact.The developed seismic microzonation maps are prepared for further introduction into the normative documents of the Republic of Kazakhstan.

Estimation of Shear Wave Structure and Horizontal to Vertical Spectral Ratio at Different Sites in Kathmandu Valley

The present study was carried out to evaluate resonant frequency of the ground and to characterize subsurface ground based on shear wave velocity structure. For this, five sites were selected such as Pulchowk, Chhauni, Gaushala, Buddhanagar and Bhainsepati. About 20 data were recorded in each site and then shear wave velocity structure and graph of amplification ratio with their spatial distribution has been established with the help of software i.e. Seisimager/Seismodule Controller. The results of both analysis methods were then compared to the amplitude of the Gorkha Earthquake and borehole data. All these data and study indicates that the Kathmandu Valley sediments are dependent on the frequency of the seismic waves and the wave velocity is greater in the peripheral region than in the central part of the Valley. The result had also shown that the presence of silty-sand, clay and loose gravel soil with low bearing capacity and elastic modulus in most of the sites are responsible for devastation. It was also noted that apart from few limitations, a non-intrusive microtremor analysis can be adopted for earthquake site characterization in the Kathmandu Valley which can be readily applied and expanded upon in future seismic hazard and microzonation efforts for Kathmandu.

Seismic Microzonation Study of South Asian Cities and Its Implications to Urban Risk Resiliency under Climate Change Scenario

In this study, an attempt has been made to review the existing framework of earthquake risk resiliency for the urban agglomerates of South Asian earthquake-prone countries (Afghanistan;Bangladesh;Bhutan, India, and Pakistan) with aim of suggesting a plausible model for earthquake risk resiliency for urban agglomerates of the region under the influence of uncontrollable climate change scenario. We demonstrated that the existing infrastructures can be retrofitted to mitigate and reduce the nature and extent of damages to structures to the greater extent whilst site response based comprehensive seismic microzonation is very much required for new settlements and for long-term sustainable urban planning by adopting multi-disciplinary investigations using integrated tools consisted of geophysical, geological, and geotechnical methodologies, which in turn help understand how and why underneath sub-surface layers get amplified to cause destruction of buildings and severe damages to critical infrastructures of South Asian Cities. It is inferred that implementation of fourth level comprehensive seismic Micro, Nano, Pico and Femto zonation study for almost all strategic cities of South Asia is a need of an hour in particular, and of the seismically prone regions of the world, in general, which would be helpful for generating a series of new parameters for development of multi-dimensional risk resilient building design codes for the safer and sustainable infrastructures of urban settlement. The methodology has wide-scale applicability to different kinds of structures and typology of the buildings.

Soil and Sediments Microzonation for Evaluation of Site Effects on Earthquake Damages in Mobarakeh, Esfahan, Iran

As an important step in effectively reducing seismic risk and the vulnerability of the city of Mobarakeh to earthquakes, a site effect microzonation Study was conducted. Seismic hazard analysis for a return period of 475 years was carried out. Data from 10 borings was collected and analyzed, geophysical surveys were conducted and seismology and geoelectric measurements taken in more than 17 stations through out the city. The study area was divided into a grid of 500×500 m2 elements and the sub-surface ground conditions were classified into 5 representative geotechnical profiles. Electric resistivity was measured in close to 17 geotechnical boreholes and surface and sub-surface sediments were collected and analyzed. Site response analyses were carried out on each representative profile using 30 different base rock input motions. Distribution maps of site periods and peak ground acceleration and old and new texture buildings through out the city were developed, providing a useful basis for land-use planning in the city.

A New Approach for Wireless Cellular Network Design

Wise arrangement of antennas is critical in wireless cellular systems for both reductions of co-channel interference (CCI) and increase the quality of service (QoS). In this paper, a novel architecture for antenna arrangement in CDMA wireless cellular systems is presented. In this architecture that we called Microzone, every cell is divided into three (or more) zones and information transmission in downlink channel is done by an antenna which is placed at the outer region of the related zone. Also, the transmitting signal by the mobile station (MS) in uplink channel is received by all the antennas of the related cell. Analytical calculations of the received signal to noise ratio (SIR) and outage probability for both microzone and used architectures show that proposed architecture has better performance in compared with the used architecture. Also, simulation results confirm lower outage probability in uplink channel for microzone architecture.

The Paradigm of the Seismic Zonation Continuality

Basic concepts of seismic zonation in Russia are the degree of intensity and soil categories that correspond to discrete structure in the ratio “seismic impact-ground reaction”. Meanwhile, the parameters of seismic effects, and the parameters of soil properties are continuous in the space. The report expounds the basic theory, adequately representing the above mentioned continuality. Thus, many the concepts of seismic zonation, used now, become either more correct, or unnecessary.

Microzoning Study for Seismic Risk Reduction in the Areas Covered Soft Soil Deposit, Japan

Kanagawa Prefecture, Japan, is just located on the tectonic plate boundary between the Philippines Sea Plate and the North American Plate. This tectonic plate boundary is called Sagami Trough and located in Sagami Bay. The 1923 Great Kanto Earthquake （Mj7.9） occurred on this plate boundary sub-ducting from Sagami Trough, the damage due to this earthquake was so huge in Kanaawa Pref., especially, along the big river, called Sagami River, located at the middle part of Kanagawa Pref. which was mostly seriously damaged. It is caused by the soft soil deposit along the Sagami River. So, in this study, we first confirmed the results of single point microtrcemor observation of about 980 points in the target area, and at this time, we tried to investigate the surface soil structure by using the miniature array microtrcemor observation, and aimed to estimate the overall ground structure of Sagami Plain. The ground structure of Sagami plains is complex, but the northern part of the plain is relatively simple and soft soil layer is shallow and stable. But the plains of the southern part, especially the west side of the Sagami River were found to be fairly soft ground. Following above, the surface soil structure in north-south direction is very clearly changed depending on the distance from the sea coast. A changing gap on the basement is very quickly appeared about 10 km far from the coast. And also, we calculated the average Vs of the surface ground and confirmed the consistency with the current ground state while confirming the historical change and the topography situation.

Seismic Site Specific Study for Seismic Microzonation: A Way Forward for Risk Resiliency of Vital Infrastructure in Sikkim, India

Seismic Microzonation comprising study of site specific seismic Microtremor (H/V ratio) is deployed to generate seismological parameters (Peak Frequency, Peak Amplification, Site Vulnerability Index) that may help estimate requisite factors for sound building design codes that can be used to construct risk resilient infrastructures. In this paper the site of Pakyong, Sikkim, India has been investigated by dividing it into three differed zones (Zone 1, Zone II, Zone III). The study area is associated with site amplification factor varying from 1.47 to 11.49 with corresponding frequency variations from 0.5 Hz - 12.5 Hz in which site vulnerability index found varied from 0.2 to 220.6. The anomalous subsurface formation with its high amplification corresponds to the centre of the Pakyong sites having conspicuous trend in NW-SE direction suggesting the existence of geological formations of Chlorite, Phyllite with intercalations of Quartzite beneath the centre of Pakyong site. The risk associated with vulnerability index for different zones maintains its variability as Zone I > Zone II > Zone III, indicating the low vulnerability index values are attributed to compact parts of the sub-surface materials with less amplifications whilst high vulnerability index of the site corresponds to relatively lower strength of the sub-surface materials and soft sediments underlying the Pakyong site which can be used for constructing risk resilient structure by enhancing the stiffness coefficient of the sub-surface by providing plausible engineering solutions for the purpose.

The New Formula of Seismic Rigidity Method

This publication is a revised version of the previous article. Seismic rigidity method despite its widespread use is the object of harsh criticism from scientists who oppose it to the methodology and results of seismological registration of earthquakes and microseisms. The article substantiates the original approach based on the solution of the direct problem of seismic microzonation for the model of real soil thickness. A new formula of the seismic rigidity method is proposed, taking into account the lithological, hydrogeological and spectral features of the soil mass, as well as the position of the new seismic scale of the SSI. The formula was tested on the example of the correct description of the features of macroseismic effects on the territory of Leninakan at the Spitak earthquake in 1988. Linear estimates according to the formula of seismic rigidity in the seismic microzoning area represent changes in seismic intensity in the most contrast way. It is shown that the real estimates of seismic intensity under strong seismic effects (by I > VII degree) will not exceed those given by the formula of the seismic rigidity method.

Soil and Subsurface Sediment Microzonation Using with Seismic Refraction Tomography for Site Assessment (Case Study: IKIA Airport, Iran)

The site effects relating to the amplification of ground motion under earthquake loading are strongly influenced by both the subsurface soil condition and the geologic structure. In this study, for site characterization at the Imam Khomeini International Airport (IKIA) area in south of Tehran, in-situ seismic refraction tomography were carried out as a part of site investigations project, in addition geologic setting, borehole drilling, ground waters information and measurements. Based on seismic refraction studies, three layers are separable which with increasing in depth the S and P wave velocity is increased and this indicates increasing in compaction of soil and geologic materials. In the second and third separated layers, the zones with low and high seismic shear wave velocity is approximately equal, and northeast and southwest of the airport site has the low velocities, in addition to containing loose soils, highly weathered stones, and low depth to groundwater. In terms of Poisson’s ratio, the most important and key installations of airport site are located in suitable positions. According to Iranian Seismic Code, most of the lands around the airport are in class 2 and 3. It seems that a fault or a discontinuity is passed from northwest to the southeast of the study area. This site, according to geological, subsurface geophysical, and geotechnical boreholes studies, is high risk-earthquake prone.

Seismic Observations and Seismic Hazard Studies in the Philippines

It has taken more than a hundred years for seismic observations in the Philippines to evolve to a modern observation system. The responsibility of seismic observations was likewise transferred from one agency to another during this same period of time. At present, the mandate of conducting seismic observations in the Philippines rests with the Philippine Institute of Volcanology and Seismology (PHIVOLCS). In 2000, through a grant aid from the Japan International Cooperation Agency (JICA), the Philippine seismic network was upgraded to a digital system. As a result, a new set of seismic monitoring equipments was installed in all of the 34 PHIVOLCS seismic stations all over the country. Digital waveforms are now available for high level seismic data processing, and data acquisition and processing are now automated. Included in the upgrade is the provision of strong motion accelerographs in all stations whose data can now be used for studying ground motion and intensity attenuation relations. The new setup is now producing high-resolution data that can now be used for conducting basic seismological researches. Earthquake locations have now improved allowing for the modeling and delineation of earthquake source regions necessary for earthquake hazard studies. Current seismic hazard studies in the Philippines involve the estimation of ground motion using both probabilistic and deterministic approaches, seismic microzonation studies of key cities using microtremor observations, paleoseismology and active faults mapping, and identification of liquefaction-prone, landslide-prone and tsunami-affected areas. The earthquake database is now being reviewed and completed with the addition of historical events and from data from regional databases. While studies of seismic hazards were primarily concentrated on a regional level, PHIVOLCS is now focusing on doing these seismic hazard studies on a microlevel. For Metro Manila, first generation hazard maps showing ground rupture, ground shaking and liquefaction hazards have recently been completed. Other large cities that are also at risk from large earthquakes are the next targets. The elements at risk such as population, lifelines, and vertical and horizontal structures for each of these urban centers are also being incorporated in the hazard maps for immediate use of planners, civil defense officials, policy-makers and engineers. The maps can also now be used to describe possible scenarios during times of strong events and how appropriate socio-economic and engineering responses could be designed. In addition, a rapid earthquake damage assessment system has been started which will attempt to produce immediate or rapid assessments including identification of elements at risk during times of strong earthquakes.

Liquefaction assessment using microtremor measurement, conventional method and artificial neural network （Case study： Babol, Iran）

Recent researchers have discovered microtremor applications for evaluating the liquefaction potential. Microtremor measurement is a fast, applicable and cost-effective method with extensive applications. In the present research the liquefaction potential has been reviewed by utilization of microtremor measurement results in Babol city. For this purpose microtremor measurements were performed at 60 measurement stations and the data were analyzed by suing Nakmaura＇s method. By using the fundamental frequency and amplification factor, the value of vulnerability index （Kg） was calculated and the liquefaction potential has been evaluated. To control the accuracy of this method, its output has been compared with the results of Seed and Idriss [1] method in 30 excavated boreholes within the study area. Also, the results obtained by the artificial neural network （ANN） were compared with microtremor measurement. Regarding the results of these three methods, it was concluded that the threshold value of liquefaction potential is Kg = 5. On the basis of the analysis performed in this research it is concluded that microtremors have the capability of assessing the liquefaction potential with desirable accuracy.

Numerical Modelling of Seismic Site Effects Incorporating Non-linearity and Groundwater Level Changes

In the past decades, the necessity for detailed earthquake microzonation studies was recognized worldwide. Therefore, different approaches were established and applied. Unfortunately, the majority of these approaches are not based on pre-existing field data but require extensive seismic measurements and investigations. Furthermore, these approaches incorporate non-linearity inadequately and cannot take groundwater level changes into account. For this purpose, notably numerical models are most suitable. These models require a good knowledge of the local geological conditions （especially of the uppermost unconsolidated units）, information about the geotechnical parameters of these units, and a hydrogeological model of the investigated area. Most of this information can be obtained from geotechnical investigations and surveys that have already been carried out in most densely populated areas. In a case study for Bucharest City, non-linear analyses were performed using software that is based on the visco-hypoplastic constitutive law. The results indicate that groundwater level changes have an important influence on duration and amplitude of ground response and thus should be considered for seismic microzonation studies. This approach ean be used to display site effects and to identify different microzones taking different earthquake magnitudes and groundwater levels into account.

Three-Dimensional Modeling of Shallow Shear-Wave Velocities for Las Vegas, Nevada, Using Sediment Type

A three-dimensional model of near-surface shear-wave velocity in the deep alluvial basin underlying the metropolitan area of Las Vegas, Nevada （USA）, is being developed for earthquake site response projections. The velocity dataset, which includes 230 measurements, is interpolated across the model using depth-dependent correlations of velocity with sediment type. The sediment-type database contains more than 1 400 well and borehole logs. Sediment sequences reported in logs are assigned to one of four units. A characteristic shear-wave velocity profile is developed for each unit by analyzing closely spaced pairs of velocity profiles and well or borehole logs. The resulting velocity model exhibits reasonable values and patterns, although it does not explicitly honor the measured shear-wave velocity profiles. Site response investigations that applied a preliminary version of the velocity model support a two-zone ground-shaking hazard model for the valley. Areas in which clay predominates in the upper 30 m are predicted to have stronger ground motions than the rest of the basin.