The study of contemporary movements and deformations occurring in the upper part of the earth surface requires high-precision geodetic measurements of displacements at specially equipped observation stations - geodynamic test sites in monitoring mode.
A "Geodynamic test site" refers to a reasonably chosen area where geodetic, astronomical, gravimetric and pitch-roll observations are made, data which are used to determine the movement of points on the earth's surface. The geodynamic sites are sometimes called as 'model areas' and survey operations are the part of a set of scientific geodetic and geophysical investigations aimed at quantifying the stability of the relative position of points on the earth's surface over time.
Among the potentially dangerous disasters for Kazakhstan, earthquakes rank first, according to the Kazakhstan Emergency Situations Agency. Approximately 6 million people in Kazakhstan and about 450,000 square kilometers of the country face danger. 27 cities and over 400 settlements are located in the earthquake-prone zone. About 40% of the republic's industrial potential is located in this area.
But due to the break up of the USSR these works were not carried out. Only in 2004, in accordance with the action plan, next stage of research and elaboration of prospects for continuation of work at the geodynamic test sites has started.
The types and scope of work performed on geodynamic test sites are as follows:
- Class 1 linear coordinate measurements at geodetic network points;
- Class I levelling by profiles;
- Class II levelling by item and network marks.
Results of the geodetic surveys are recorded in scientific and technical reports and submitted to the RNE "NCGF".
The observations of the vertical movements of the Earth's crust at the "Almaty Geodynamic Testing Site" have been carried out since 1968-1971, and by now on the line-corner network points of the testing site, including measurements in 2016, between 22 and 54 class I and II levelling cycles were carried out, on the “Shelek testing site” since 1975 and by now, 23 class II levelling cycles have been completed on the linear and angular network of the site.
Crustal deformation data from the Almaty Geodynamic Testing Site obtained from the 2016 geodetic measurements, and by geodetic measurements of 2018, land surface deformation data at the Shelek Geodynamic Testing Site have an amplitude of -3.3 to +0.6 mm/year and do not exceed the possible accumulation of measurement errors ± 3n√L.
The observations of the vertical movement of the Earth's crust at the “Zaisan geodynamic testing site” on the lane-and-corner network points have been peroformed from 2007 to 2016, and up to 10 class II levelling cycles are performed. The crustal deformation data obtained from the 2016 geodetic measurements at the Zaisan geodynamic test site has an amplitude of -2.3 to +0.6 mm/year and does not exceed possible measurement error accumulations ± 3n√L.
The observations of the vertical movement of the Earth's crust at the Zhambyl Geodynamic Test Site, using line-and-angle network points, have been resumed in 2004. Approximately 13 Class I and II levelling cycles were carried out from 2004 to 2016. The crustal deformation data from the 2016 geodetic measurements at the Zhambyl Geodynamic Test Site has an amplitude of -0.12 to +0.71 mm/year and does not exceed possible measurement error accumulations ± 3n√L.
Based on the results of the relevelling in 2016, it can be concluded that the numerical values at the aforementioned polygons do not have the pronounced anomalous nature that precedes strong earthquakes. All obtained quantitative characteristics of deformations can then be used in the design of hydraulic structures, oil and gas pipelines and systems for the needs of the national economy, where knowledge of the stability in time of individual sections of the earth's surface is needed.