Sunday, 16 June, 2019

Consequences

 

Under the forecast earthquake damage,  the assessment of possible consequences of severe and catastrophic earthquakes, which can cause irreversible changes in the geological environment, the destruction of industrial, agricultural and civil projects is understood. Additionally, there may be social problems associated with the injury, damage due to disruption in transport and communications, the deterioration of living conditions, migration from disaster areas, reduce labor activity. All marked problems provide considerable economic losses across the state. Therefore, one of the laboratories of the Institute of Seismology (head - T.Abakanov) deals with  the development of integrated forecasting of economic and social damage from earthquakes and related secondary factors.

Theoretical studies is directed to the development of assessment criteria of the expected loss from the earthquakes of varying strength by studying the effects of known catastrophic events in different countries. In this regard, the following results are obtained:

· A method and a program of constructing predictive isoseismals intensities of expected earthquakes in the Republic of Kazakhstan are developed, which take into account the depth of the epicenter, magnitude, location, and are confined to еру areas of expected  earthquakes.

· Based on the collection, processing, analysis and interpretation of survey effects of destructive earthquakes occurred in the world in the past 100 years, the methods and tools for socio-economic impact of the destruction of the buildings in the settlements due to seismic effects intensity of 6 to 10 scores have been developed.

· The methods of calculation are developed, the  nomograms for obtaining optimal parameters of flexibility, reinforcement ratio, the class of concrete statically indeterminate bearing reinforced concrete buildings in the elastic and elastic-plastic stage of deformation under the effect of the type of seismic loads are made.

· A method of calculation of frame buildings with diaphragm for seismic effects, taking into account the full chart of material deformation structures using accelerograms real and artificial earthquakes is developed.

· The methods, algorithms and software for calculation of system "soil-structure" on seismic effects including damage to structures and structural elements of irreversible plastic deformation in soils are developed.

· For the large-panel and frame buildings, with the self-supporting walls, the analytical expressions for determining the periods of free oscillations depending on height of buildings  are obtained.

· A method of the exact analytical calculating of the high-rise structures, such as chimneys, is developed, which takes into account a possible period of free oscillations of the cross section of the construction according to its height, which can be a resonance in dependence on  the dominant periods of seismic ground motion.

· The new technical solutions for aseismic buildings and structures are developed,  which have the properties of high seismic energy dissipation of system and escape from the resonance, firming performance and reliability as well.

· On the example of Almaty,  a new technique for mapping of seismic zoning is developed on the base of the  using the spectral characteristics of soils, which takes into account density and performance characteristics of the medium of the sedimentary cover. A series of maps will allow, on the design stage, to predict and avoid resonant vibrations of the soil and building.

The practical implementation of research is as follows:

· The determination of motion parameters of complex engineering structures, using through seysmotelemetric equipment, has been held naturally, when the measuring devices are installed at the site and the recording equipment is fixed to the base point, placed at a considerable distance from the first, and all information is transferred from the measuring instruments into the  recording channels using the to seismotelemetric communication. The using this method allows one to save time, eliminate crashes when registering vibrations facilities, ensure reliable operation of the equipment in the field and during earthquakes.

· The field studies to determine the dynamic characteristics of vibration waterfront of Kapchagai hydroelectric (logs and channel dams and rock outcrop) are carried out, the model of the riverbed dam is tested as well.  For this purpose, the Institute of Seismology made a seismoplatform to test the structures, the models of buildings, and the soils on the alternating dynamic loads such as seismic, operating in a given amplitude and frequency mode. The main technical characteristics of a seismoplatform: the maximum weight of subjects designs - 2 tons, the range of frequencies - 0.1 50 Hz,  the amplitude of displacement – 2, 5,  10 mm. Using the seismoplatform, we tested the small-scale model of the dam on the alternating types of seismic load. This research allowed  us to assess the real seismic reliability of objects of the  Kapchagai hydropower waterfront.

· The methods of testing on earthquake-resistant of the design of special purpose (tunnels, buildings cascade mountain rivers, high-pressure pipelines and other structures) in the high mountains and rugged terrain are approved.

The obtained results can be used not only in Almaty and seismically active regions of the Republic of Kazakhstan, but also in the neighboring countries and other countries whose territories are vulnerable to earthquakes. Technical solutions Earthquake Engineering, calculation methods, nomograms and software package can be used by the research and design organizations.

On December 1, 2003 at 07 hours 39 minutes of Almaty time, a severe earthquake occurred on the adjacent territory of China and Kazakhstan.

According to the Central Seismic Observatory "Almaty", the epicenter of earthquake was located at 310 km south-east of the city of Almaty. Coordinates of the epicenter of the earthquake 42 ° 52 'N,  80 ° 39' E, magnitude Ms = 5.7 (energy class K = 14.0). Most strongly in Kazakhstan, the  earthquake was felt in the Raiymbek area of Almaty region. In a limited area within the epicentral zone, the intensity of its display on the surface of the earth reached 7 points on the MSK-64 scale.

Seismotectonic conditions in the earthquake area on 01.12.2003 is related to  the South Ketmen and adjacent to the south of it the Basylutausk seismogenic zones. The most likely faults, which are confined to areas of focus of the earthquake happened, is a zone of convergence of the Syumbinsk, Basulytausk and the groups of Chuladyrsk faults with northeast strike. At the center of seismic zoning map, the foci is located in the  eight point of shock, the pleistosest area has an elongated shape and the major axis of the ellipse coincides with the strike of the faults to which this outbreak is attached.

The macroseismic team has  surveyed the 40 villages. According to the results,  a map of the macroseismic survey isoseismals is constructed,  on which the 7, 6, 5 and 4-point zone shaking in Kazakhstan are shown. The Sumbe town, located of 20 kilometers from the epicenter of the earthquake,  has suffered more strongly. Here, the vast majority of the private buildings are of adobe. There are buildings of brick, mainly administrative purposes (school, city administration, ambulance). There are damages expressed by deep through cracks in the walls, drop the parts of chimneys. Some  houses have 4 degrees of destruction as the breaches in the walls, and their departure from the ceiling. In the buildings of brick cruciform, the cracks in the walls appeared, and a spalling of large pieces of plaster took place. Most people were scared and ran out of  buildings.  Many people hardly kept on their feet, many sick. In a 6-point scale,  almost all adobe houses were observed cracks in the corners of rooms. In some buildings of this type were observed through cracks in the walls. In brick buildings, the damage was in the form of  the hairline cracks in the corners. In some of them the joints in slabs were developed. In the school, in the village of Tekes,  the cracks up to 5 cm between the supporting walls and support beams median appeared. In many classrooms, the glass were  broken. The earthquake of December 1, 2003 in the border area of China, based on the total seismicity,  is considered as a natural manifestation of the seismic regime in the region.

 

Damage to houses in the village Sumbe

 

Area  of earthquake  of 01.12.2003.

red star - the epicenter of the earthquake, triangles: green - complex, blue - geophysical, yellow - seysmotelemetricheskie and red - built station.